easyraid Generic Software Manual SCSI(Ultra 320 ) / FC(2Gb) Serial ATA II Disk Array Systems

Transcription

1 easyraid Generic Software Manual SCSI(Ultra 320 ) / FC(2Gb) to Serial ATA II Disk Array Systems August 2005 Version 1.0

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3 Ultra 320 SCSI to Serial ATA II Disk Array System & Fibre Channel to Serial ATA II Disk Array System easyraid Generic Software Manual

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5 Table of Content Chapter About this manual RAID terminology 1-1 Chapter System diagnostic during boot cycle LCD screen symbols (drive status) Menu navigation and mute system beeper from front panel Quick Setup Flow chart and procedures 2-4 Chapter Advanced Setup - Flow chart and procedures Setup the connection to RAID system Setting real time clock(rtc) and checking drive health Creating and slicing arrays Assign SCSI/FC Channel ID & Mapping LUN to hosts Save Configuration & System initialization Connecting the RAID system to a host computer Deleting or reconfiguring an array Deleting a slice of an array Expanding an Array Regenerating an arrays parity and performing a parity check Configuring SAN masking for FC disk array 3-13 Chapter Disk Scrubbing Bad block detection and parity correction Auto Shutdown RAID system in critical condition Disk Self Test Check drive healthy in RAID system Disk Clone Manually cloning a failing drive SMART Predicting a drive failure and automatic disk cloning AV Streaming - Performance-critical streaming application PreRead cache - Enhancing sequential read throughput Alignment Offset Multipath IO S/W (PathGuard) on Window OS 4-12 Chapter Event Severity Event List 5-1 Appendix I Upgrading Firmware of the RAID System I Pre-configured RAID parameters V On-line and Off-line effective RAID parameters VI Recording of RAID Configuration VII C i

6 Revision History Version Date Remarks 1.0 Aug, 2005 Initial release ii

7 Chapter 1 Introduction This chapter contains an overview of easyraid disk array generic software. It contains the following topics: Section 1.1, About this manual Section 1.2, RAID terminology 1.1 About this manual This manual has the following chapters and appendix: Chapter 1, Introduction, describes RAID terminology and basic SCSI concepts. Chapter 2, Quick Setup, introduces the procedure to create single array using the front panel Chapter 3, Advanced Setup, introduces advanced configuration flow to create and delete multiple arrays and slices through RS-232 and RJ-45 port Chapter 4, Using advanced functions of RAID system, contains proprietary RAID functions and configuration flow and condition. Chapter 5, Event messages of the RAID System, lists the message recorded by RAID system. Appendix, Upgrade firmware, pre-configured, online and offline effective RAID parameters. 1.2 RAID terminology Redundant Array of Independent Disk (RAID) is a storage technology used to combine multiple inexpensive drives into a logical drive to obtain performance, capacity and reliability over single-disk storage. RAID 0 - Disk Striping In RAID 0, data is divided into pieces and written to all disks in parallel. This process is called striping because the pieces of data form a stripe across multiple disks. This improves access rate, but makes availability lower, since a single disk failure will cause the failure of the array. A RAID 0 array is unsuitable for data that can not easily be reproduced, or for mission-critical system operation. Figure 1- RAID 0(Disk striping) 1-1

8 RAID 1- Disk Mirroring In RAID 1, data is duplicated on two or more disks to provide high access rate and very high data availability. This process is called mirroring. If a disk fails, the RAID controller directs all requests to the surviving members. Figure 2- RAID 1(Disk mirroring) RAID 3- Disk Striping with dedicated parity In RAID 3, data is divided into pieces and a single parity is calculated. The pieces and parity are written to separate disks in parallel. The parity is written to a single dedicated disk. This process is called striping with dedicated parity. The parity disk stores redundant information about the data on other disks. If a single disk fails, then the data can be regenerated from other data and parity disks. Figure 3- RAID 3(Disk striping with dedicated parity) 1-2

9 RAID 5- Disk Striping with distributed parity In RAID 5, data is divided into pieces and a single parity is calculated. The pieces and parity are written to separate disk in parallel. The parity is written to a different disk in each stripe. Parity provides redundant information about the data on other disks. If a single disk fails, then the data can be regenerated from other data and parity disks. Figure 4- RAID 5(Disk striping with distributed parity) RAID 6- Disk Striping with two sets of distributed parities In RAID 6, data is divided into pieces and two sets of parities are calculated. The pieces and parities are written to separate disks in parallel. The two parities are written to different disks in each stripe. Parity provides redundant information about the data on the RAID member disks. If two disks fail at the same time, the data can still be regenerated from other data and parity disks. The RAID 6 algorithm uses two independent equations to compute two sets of parity, which enable reconstruction of data when two disks and/or blocks fail at the same time. It greatly improves the data availability. Figure 5- RAID 6 (Disk striping with two sets of parity- P and Q) 1-3

10 RAID TP(Triple Parity) - Disk Striping with triple distributed parity In RAID TP, data is divided into pieces and three sets of parities are calculated. The data pieces and the parities are written to separate disks in parallel. The three parities are written to different disks in each stripe. Parity provides redundant information about the data on the RAID member disks. If three disks fail at the same time, the data can still be regenerated from other data and parity disks. The RAID TP algorithms use three independent equations to compute triple parity, which enable reconstruction of data when three disks and/or blocks fail at the same time. It greatly improves the data availability. Figure 6- RAID TP (Disk striping with triple parity P, Q and R) JBOD Just a Bunch of Disks JBOD stands for just a bunch of disks. In JBOD mode, the host will see each drive as an independent logical disk. There is no fault-tolerance in JBOD. Figure 7- JBOD (Just a Bunch Of Disks) 1-4

11 NRAID Non-RAID In NRAID mode, all drives are configured as a single logical drive without fault-tolerance. The total capacity of NRAID will be the sum of each drives. Figure 8- NRAID (Non-RAID) RAID 0+1 Disk striping with mirroring RAID 0+1 is a combination of RAID 0 and RAID 1 to form an array. RAID 30 Striping of RAID 3 RAID 30 is a combination of RAID 0 and RAID 3 to form an array. It provides better data redundancy compared with RAID 3. RAID 50 Striping of RAID 5 RAID 50 is a combination of RAID 0 and RAID 5 to form an array. It provides better data redundancy compared with RAID 5. Summary of RAID Levels The following table provides a brief overview of RAID levels. A high data availability number indicates high fault tolerance. RAID Level Description Capacity Data Availability Minimum drives RAID 0 Disk striping N 0 1 RAID 1 Disk mirroring N/N 5 2 RAID 3 Striping with dedicated parity N RAID 5 Striping with distributed parity N RAID 6 Striping with 2 sets of parity N RAID TP Striping with triple parity N RAID 0+1 Disk striping with mirroring N/2 2 4 RAID 30 Striping of RAID 3 N RAID 50 Striping of RAID 5 N NRAID Non-RAID N 0 1 JBOD Just a bunch of disks N

12 SCSI specification The RAID system supports standard SCSI specification as below. Note that it s recommended to use an external SCSI cable as short as possible. SCSI Type Data bit Data Rate Max Cable Length Max SCSI devices SCSI MB/s 6 m 7 Fast SCSI 8 10 MB/s 3 m 7 Fast Wide SCSI MB/s 3 m 15 Ultra SCSI 8 20 MB/s 1.5 m 7 Ultra Wide SCSI MB/s 1.5 m 15 Ultra 2 SCSI 8 40 MB/s 12 m 7 Ultra 2 Wide SCSI MB/s 12 m 15 Ultra MB/s 12 m 15 Ultra MB/s 12 m

13 Chapter 2 Quick Setup This chapter introduces a simple way to configure the RAID system. It is written for those who use easyraid RAID system for the first time and want to create an array quickly. It includes these topics: Section 2.1, System diagnostic during boot cycle Section 2.2, LCD screen symbols (drive status) Section 2.3, Menu navigation and mute system beeper from front panel Section 2.4, Quick Setup - Flow chart and procedures 2.1 System diagnostic during boot cycle Figure 9 displays a flow chart of the RAID system self-test on boot-up. During boot-up, the RAID system executes CPU, peripheral device, host and, disk chipset initialization. It consists of three modes (A,B,andC). A - Initial RAID status The RAID system has not been configured. Drives have not been installed; there is no RAID configuration present in the hard drives and RAID controllers NVRAM. B - RAID system initializing The RAID system is configured and drive initialization has begun. C - RAID system exists The RAID system has been configured. There is a RAID configuration present in hard drives and RAID controllers NVRAM. 2-1

14 Figure 9 - System Diagnostic Flow Note: The RAID configuration is stored both in a reserved area of the hard drives and RAID controller s NVRAM after an array set is created. 2.2 LCD screen symbols (drive status) The LCD screen shows an overview of RAID system drives status. This section explains the meaning of symbols that appear on the LCD screen. Symbol Meaning R The drive has an error or a fault I RAID system is identifying the drive S Global hot-spare drive X No drive installed or drive is offline W Warning Too many bad sectors or unrecoverable data blocks in the drive or drive triggered SMART failure warning after running Disk SMART test A The drive is being added to an array either during online expansion or rebuilding C A clone drive (target drive) 1~8 Array group number that a drive belongs to J The drive is in JBOD mode ( No configuration mode) 2-2

15 Below are some examples. Example Description LCD Screen Model Name: easyraid Q16 Disk1to16areallinJBODmode RAID initial status ( No RAID configuration mode) Two arrays with one global hot-spare drive Array1@RAID Level 5 Model Name: easyraid Q16 Disk 1 to 9 are members of Array1 Disk 10 to 14 are members of Array2 Disk 15 is a global hot-spare drive Disk 16 is not installed or offline Array 1 RAID Level 5 Disk 1 to 9 are members of Array1 Array2 not created yet Array 2 RAID Level X not available No drive member exists 2.3 Menu navigation and mute system beeper from front panel The RAID system can be configured using the front panel function keys. Menu Navigation from LCD Panel Key ESC Enter Description UP arrow key. To select options or scroll forward each character during data entry Down arrow key. To select options or scroll back each character during data entry To escape or go back to previous menu screen To go to a submenu or to execute a selected option Mute System beeper from LCD panel The RAID system emits a beeping sound periodically when an error or failure occurs in the disk array. This audible alert can be turned off temporarily for the current event by pressing UP and Down key twice simultaneously. The beeper will activate again if a new event occurs. 2-3

16 2.4 Quick Setup Flow chart and procedures This section provides a quick way to configure the RAID system with one-click using the front panel. The RAID system will automatically create a single array and map it to its first host channel. Before you begin It s not recommended to connect the RAID system to the host computer before completing configuration and initialization. If connected during configuration process, resetting the controller could lead to occasional host server error messages like parity error or synchronous error. Note: To ensure power redundancy, connect the power supplies to a separate circuit, i.e. one to a commercial circuit and one to a UPS (Uninterruptible Power Supply) Using the unit without a UPS will greatly increase the chances of data and RAID configuration corruption. Quick Setup Flow Figure 10 shows the quick setup from the front panel function keys. Figure 10- Quick Setup Flow 2-4

17 Quick Setup Procedures Step1. Insert drives into RAID system Make sure all of the drives are mounted securely to the disk trays and insert disk trays into disk slots Step2. Power ON RAID system Note: After powering on. the LCD status should display as seen to the right. Ex: Model Name: easyraid Q16 Step3. Enter password 0000 to login Main Menu from LCD Press Enter key. Enter Passwd message will appear on the LCD screen. Use or to select each character and select 0000, press Enter to proceed Note: 0000 is the default password. Step4. Select RAID level in Quick Setup Go to Quick Setup->RAID Level Use or key to select the desired level. For example: 6+spare, Select Yes and press Enter to proceed. Note: If a spare drive is not selected or reserved, all of the installed disks will be configured as a drive member of Array 1. RAID level options in quick setup: 0/1/3/3+spare/5/5+spare/6/6+spare /TP/TP+spare/0+1/30/50/NRAID TP: Triple Parity allows three drives to fail inasinglearray Step5. Automatic system initialization After setup, the system will begin to initialize. It may take several hours depending on the total capacity of the array. Step6. Connecting host computer to 1 st host channel of RAID system Power off RAID system and connect 1 st host channel of RAID system to host computer. Power on RAID, wait for the unit to completely power on, then power on host computer. Note: Before connecting RAID system(scsi) to host server(step 6) 1. Check the SCSI/FC ID of RAID system and the HBA to ensure that they are not sharing the same ID with another device on the same channel. The default SCSI ID of RAID system is 0, Fibre ID setting is Auto. 2. In a SCSI daisy chain, SCSI termination is required on the last SCSI device. Make sure it is properly terminated on SCSI bus. 3. Before you disconnect or connect a SCSI cable from the RAID system, power off the host computer, than the RAID system for safety. Also note, SCSI bus does not support hot-plug function. 2-5

18 Chapter 3 Advanced Setup The RAID system can be configured using a terminal emulation program, such as HyperTerminal in Windows. This allows the user to create multiple RAID arrays and slices via RS-232 or RJ-45 port. It includes the following topics: Section 3.1, Advanced Setup - Flow chart and procedures Section 3.2, Deleting or reconfiguring an array Section 3.3, Deleting a slice of an array Section 3.4, Expanding an array Section 3.5, Regenerating an arrays parity and performing a parity check Section 3.6, Configuring SAN masking for FC disk array 3.1 Advanced Setup - Flow chart and procedures This section introduces the advanced setup flow chart and detailed procedures to configure the RAID system for multiple array groups, slicing, and LUN mapping to host channels. There are three methods to configure the RAID system. 1. Front panel function keys (Refer to Chapter 2 Quick Setup) 2. VT-100 emulation program via RS-232 serial port or RJ-45 LAN port 3. Cross-platform Global Net software via RJ-45 LAN port Figure 11- Advanced Setup Flow 3-1

19 3.1.1 Setup the connection to RAID system In this section, it introduces how to set up a VT-100 emulation program via RS-232 and RJ-45 port. 1. Using RS-232 serial port To set up the serial port connection, follow these steps. This example will use Hyperterminal for Windows. Step1. Use a serial cable (null modem) to connect the RS-232 port of RAID system to the management console (or host computer) Step2. Start Hyper Terminal on the management console For Windows, click Start->Programs->Accessories->Communication, then select Hyper Terminal The Hyper Terminal window appears and if the Location Information window appears, skip it Click Cancel -> Yes -> OK Step3. Make a new connection When Connection Description dialog box appears, give the new connection a name for example: Disk Array, Click OK to continue Step4. Select PC serial COM port Click Connect using field and select COM1, then click OK Note: If you are unsure which COM port to use or if the connection does not work, repeat the above steps and try a different COM port. 3-2

20 Step5. Set the COM port properties In Port Setting tab, select Bit per second => Data bit => 8 Parity => None Stop bits => 1 Flow control => None Click OK to continue Step6. Display RAID utility interface Press <Ctrl>+<D> to display the main screen of RAID utility. Tip: <Ctrl>+<D> can refresh the screen information 2. Using RJ-45 LAN port (Optional) To set up the RJ-45 LAN port connection, follow these steps. Step1. Use a RJ-45 cable to connect the RJ45 port of RAID system to an ethernet switch Step2. Start Hyper Terminal on the management console Repeat the same procedure in RS-232 setup. Step3. Make a new connection Repeat the same procedure in RS-232 setup. 3-3

21 Step4. Select TCP/IP (Winsock) connection Click Connect using field and select TCP/IP (Winsock), then click OK Note: Not all of easyraid disk array support TCP/IP (Winsock) via VT-100 emulation program, Contact easyraid support for more information. Step5. Assign IP address of RAID system Obtain IP address automatically The default ethernet setting of RAID system is DHCP enabled. Connect the RJ-45 port of RAID system to a dynamic (DHCP) network. An IP address will be automatically assigned to the RAID system. Use Up and Down arrow key to navigate the LCD screen to get the IP address of the RAID system. Assign IP address manually The RAID system can also be assigned with a static IP address via LCD manually. 1. Enter password 0000 from LCD panel to login in RAID utility 2. Use arrow key to go to System Params->Ethernet Setup->DHCP, select Disable 3. Return to Ethernet Setup tosetthenetwork manually. Use Up and Down arrow key to assign, IP address: xxx.xxx.xxx.xxx Netmask: xxx.xxxx.xxx.xxx Gateway: xxx.xxx.xxx.xxx Note: The default Ethernet setting of RAID system: IP address: Netmask: Gateway: Key in the IP address of RAID system in Host address field of Hyper Terminal And set the Port Number to4660. Click OK to continue. Step6. Display RAID utility interface Repeat the same procedure in RS-232 setup. 3-4

22 RAID utility Interface You will see the following RAID utility interface after you access the RAID controller via the RAID system COM port or LAN port for the first time. Use the following hot keys to explore the menu tree or execute RAID functions. Tab A Z S X ESC Enter Ctrl+D Switch between Main Menu and Output Area window MovecursorUP MovecursorDOWN Scroll UP one page in output area Scroll DOWN one page in output area To escape or go back to previous menu screen Enter a submenu or to execute a selected option Display or re-flash menu screen Note: The default password to enter Main Menu of RAID system is 0000(four zeros) 3-5

23 Main Menu The following figure is the main menu for SCSI/FCRAIDsystemafterloggingintothemonitor utility using a VT-100 terminal program Setting real time clock(rtc) and checking drive health In order to perform advanced RAID functions, such as scheduled disk scrubbing, SMART disk cloning and recording the date and time of event messages, etc the real-time clock must be setup. Refer to Chapter 4 for detailed information about disk scrubbing, SMART. Real Time Clock menu tree Step1. Go to Main Menu->System Params->RTC Step2. Select Set RTC to set the clock for RAID system in the format of MM/DD/YY W HH:MM Symbol Range Description MM 01~12 Month DD 01~31 Day YY 05 Year W 1~7 Day of the week 1: Monday; 2: Tuesday; 3:Wednesday; 4: Thursday; 5: Friday; 6: Saturday; 7: Sunday HH 01~24 Hour MM 00~59 Minute 3-6

24 Checking drive health Go to Main Menu->Utility->Disk Utility->Disk Self Test andrun ShortSelfTest for all disks. If the suspected disk fails to pass Short Self Test, it s recommended to replace a new drive or run Extended Self Test to further investigate drive health. For more information about Disk Self Test, see Chapter 4, Section Creating and slicing arrays Below is the flow chart to create array groups and divide it into slices. Figure 12- Multiple Arrays & Slices Creation flow 3-7

25 Array Params menu tree The RAID system can be configured up to 8 array groups with different RAID level and each array group can be divided into a maximum of 16 slices. Follow the following steps to create and slice an array. Step1:ChoosethestripesizeofRAIDsystem Go to Main Menu->Array Params->Stripe Size and select a stripe size based on what kind of application behavior will be applied. Recommendation: 1. Using the default stripe size, 128 sectors (64 KB), should be sufficient for most applications. 2. Choose 256 sectors (128KB) stripe size if host application is mainly sequential read/write IO 3. Choose 32 sectors (16KB) stripe size if host application is mainly random read/write IO Note: Once the stripe size is selected, it will apply to the whole RAID system. All arrays will use this specified stripe size. Step2: Decide whether or not to create an over-2tb slice (Optional). Skip this step if you do not wish to create a slice over 2 TB. Currently, there are two ways to break 2 TB limitation per slice. One is to change the sector size or enable 16 byte CDB(Command Descriptor Block) 2.1 Goto Main Menu->Array Params->Slice Over 2 TB and select enable 2.2 Select Sector size or 16 byte CDB Note: 1. Currently, Sector size option is supported for Microsoft Window 2000/2003/2003 SP1 16 Byte CDB option is supported for Window 2003 server SP1 2. If Slice Over 2 TB option is disabled, after initializing an array if the capacity is over 2 TB, 3-8

26 the RAID system will automatically create multiple slices limited at 2TB. Step3: Create multiple arrays groups 3.1 Goto Main Menu->Array Params, then select an array number 3.2Goto RAID Level, and select a RAID level 3.3 Select drive members of the current array. Note: Hot-spare disk is not a member of an array, reserving at least one spare drive in a unit is recommended. 3.4 Press<Escape> until the main menu appears 3.5 Repeat the step 3.1~3.4 to create more array groups. Step4: Creating slices of an individual array 4.1 Goto Main Menu->Array Params, then select the array you want to divide into slices. 4.2Goto Slice, and select the first slice - Slice 00, type the size in megabyte(mb), then press <Enter>. Note: The output area will display the slice size that has been created. 4.3 Repeat Step 4.2 to create the next Slice 01 until the array is divided as planned Note: It is not allowed to create slices randomly. Create slices in ascending sequence, for example: Slice 00->Slice 01 ->Slice 15 Step5: Setting initialization mode Initialization mode has two options, foreground and background. With foreground initialization, an array will be accessible after initialization is completed. With background initialization, an array will be accessible during initialization. 5.1Goto Main Menu->Array Params, and select the array group 5.2Goto Initialization Mode, and select a mode you prefer, for example: background, thearray can be accessed during initialization. Note: It may take several hours to complete foreground initialization depending on the total capacity of an array.it s recommended to set foreground mode to double check drive health during RAID system initialization Assign SCSI/FC Channel ID & Mapping LUN to hosts Every device requires a unique SCSI or Fibre channel ID. A SCSI chain can support up to 15 SCSI devices with Wide function enabled. A Fibre loop can support up to 125 FC devices. If there are multiple host computers that require access to the same storage device (LUN) than there must be clustering or multipath I/O software installed on these computers. Note: easyraid RAID also supports host-based multipath I/O software PathGuard. 3-9

27 SCSI/Fibre Params menu tree Assigning SCSI or Fibre Channel ID Setting SCSI ID 1. Go to Main Menu->SCSI Params, then select a SCSI channel for example: SCSI CH1 2. Select Set SCSI ID, then select a SCSI ID 3. Repeat Step 1~2 to set another SCSI Channel ID Setting Fibre ID 1. Go to Main Menu->Fibre Params, then select a Fibre channel for example: FC CH1 2. Select Set Loop ID, then select Auto or key in a number (0~125) manually. 3. Repeat Step 1~2 to set another Fibre Channel ID Note: 1. Check the SCSI/FC ID of RAID system and the HBA to ensure that they are not sharing the same ID on the same channel. The default SCSI ID of RAID system is 0, Fibre ID setting is Auto. 2. In a SCSI daisy chain, SCSI termination is required at the last SCSI device. Make sure it is properly terminated on the SCSI bus. 3. QAS(Quick Arbitration Select) setting is required for Ultra 320 devices. If the QAS setting on the RAID system differs from the HBA, there will be problems accessing the RAID unit from the host. Refer to the following table to properly set QAS option in SCSI Params. The RAID system and HBA require the same QAS setting. HBA vendor Adaptec/ATTO LSI QAS setting Enable(Default) Disable 3-10

28 Mapping LUN(s) to a host channel. LUN mapping is the process to make a slice visible to a desired host channels. Each LUN will appear as a storage device to the host computer. 1. Go to Main Menu, then select SCSI Params for SCSI RAID or Fibre Params for Fibre RAID 2. Select a specific host channel, for example: SCSI CH1 or Fibre CH1 3. Go to Lun Map, and select a LUN number. 4. Select an array, then select the desired slice to map to the chosen LUN Ex. SCSI Params -> SCSI CH1 -> LUN Map -> LUN 0 -> Array 1 -> Slice0 This will map Slice 0 of Array 1 to LUN 0 of SCSI Channel 1 Note: 1. The same slice may be mapped to multiple LUNs on separate host channels, but is only applicable for clustering or multipath environments. 2. Selecting Disable will delete a LUN map. Deleting a LUN map will not delete the data contained in the array or slice. 5. Press the <Escape> key to return to the Main menu 6. Repeat step 1~5 for each slice until all slices are mapped to a LUN Save Configuration & System initialization Go to Main Menu->Save Config and select Save & Restart, select Yes tocompleteraid configuration. Note: TheRAIDconfigurationisstoredinareservedareaoftheharddrivesandtheRAID controller s NVRAM after the array is created. After the RAID system reboots, it will enter system initialization. It may take several hours to complete depending on the total capacity of an array Connecting the RAID system to a host computer Power off the RAID system and connect to a host computer or FC switch Power on the RAID system, after it has completely powered on, power on the host computer Note: The host computer should be the last device to power on. Summary of Advanced Setup Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Step 7 Step 8 Insert drives into RAID system Power ON RAID system Setup the connection to RAID system (via RS-232 or RJ-45) & Setting real time clock Checking drive health(short Self Test) Creating and slicing arrays AssignSCSIorFCchannelIDandmappingLUNstoahostchannel Save configuration & system initialization Connecting the RAID system to a host computer 3-11

29 3.2 Deleting or reconfiguring an array Before deleting or reconfiguring an array backup all required data. To reconfigure an array with different drive members, RAID level, or stripe size, delete the existing array and then reconfigure the array. To delete an array, follow these steps: Step1. Go to Main Menu->Array Params, and select the array you want to delete Step2. Go to RAID Level, and select None Step3. Select Yes toproceed Step4. Go to Main Menu->Save Config and select Save to NVRAM. The RAID system will not automatically reboot, and the array will be deleted immediately. Caution: Deleting an array will destroy all data contained in that array. 3.3 Deleting a slice of an array Follow these steps to delete a slice Step1. Go to Main Menu->Array Params, and select the desired array Step2. Go to Slice, and select the last slice in the array, for example: Slice 02 Step3. Type 0 (MB) to delete Slice 02 Step4. Return to Slice then select Slice 01, type 0 (MB) to delete Slice 01 Step5. Go to Main Menu->Save Config, then select Save to NVRAM totakeeffectthechange. Delete slices in a descending sequence. Similarly, you can follow the same steps to change the slice size. Note: The use of a third party storage resource management (SRM) software or an OS file management program to divide or stripe a slice may lead to data fragmentation that causes decreased I/O performance of the RAID system. Caution: Deleting a slice will lose all data contained in that slice. Backup your data before deleting or changing the slice size 3-12

30 3.4 Expanding an Array Follow these steps to expand an array. Step1. Go to Main Menu->Array Params->Expand Array, and select the desired array Step2. The disk numbers will then prompt, select a number that will add to the array RAID system then enters on-line expanding process automatically After array expansion is complete, a new slice will be created from the added capacity. Refer to Section to map the new slice to the desired host channel/lun. Note: Expanding an array will impact system performance, performing array expansion during off-peak time is recommended. 3.5 Regenerating an arrays parity and performing a parity check RAID parity might become inconsistent with data after extended periods of time. Users can re-generate array parity or perform a parity check to ensure data integrity. Follow the following steps to expand an array. Step1. Go to Main Menu->System Params then select Init Parity to regenerate RAID parity or Parity Check to verify the parity consistency. Step2. Select the desired array, then select Start to proceed Note: After the RAID system starts parity check if a parity inconsistency is detected, the parity check will stop and report a discrepancy. Refer to Chapter 4, section 4.1 about disk scrubbing to correct parity errors. Note: Init Parity and Parity Check can only be performed when RAID system is in an optimal condition. 3.6 Configuring SAN masking for FC disk array SAN masking is a RAID system-centric enforced method of masking multiple LUNs behind a Fibre channel port. As Figure 13 shows, with SAN masking, a single large RAID device can be subdivided to serve or block a number of different hosts that are attached to the RAID through the SAN fabric. The host servers that access a certain LUN through a particular port can be masked from accessing other LUNs through the same port. SAN masking can be setup on the RAID system or the host computers HBA. Masking a LUN at the device level is more secure than masking at the host computer, but not all RAID systems have LUN masking capability; therefore, some HBA vendors allow persistent binding at the driver-level to mask LUNs. 3-13

31 SAN Mask menu tree Figure 13- SAN Mask example Follow the following steps to enable SAN mask. Step1. Go to Main Menu->Fibre Params->SAN Mask->Supporting, and select the desired Fibre channel, for example: FC CH1, thenselect Disable Note: The default setting, Enable, allows all SAN host computers to access all LUNs via the fibre channel port. Step2. Go to SAN Mapping->FC CH1->Host 1, select LUN0, and select Yes. Step3. Repeat Step 2 to map, Host 2->LUN1, Host 3->LUN2, Host 4->LUN3, Host 5->LUN4 Step4. Go to Edit WWN Tbl, then type 8 byte WWN of FC HBA which is installed in each host server. Refer to your FC HBA documentation for more details. 3-14

32 Chapter 4 Using advanced functions of RAID system This chapter further introduces the advanced RAID functions. It covers the following topics: Section 4.1, Disk Scrubbing Bad block detection and parity correction Section 4.2, Auto shutdown RAID system in critical condition Section 4.3, Disk Self Test Drive health test in RAID system Section 4.4, Disk Clone Manually cloning a failing drive Section 4.5, SMART- Predicting a drive failure and automatic disk cloning Section 4.6, AV Streaming Performance-critical streaming application Section 4.7, Pre-Read cache Enhance sequential read throughput Section 4.8, Alignment Offset MultiPath I/O Software (PathGuard) for Windows OS 4.1 Disk Scrubbing Bad block detection and parity correction Objective With the increasing capacity size of hard drives, storage subsystem vendors face the challenge of handling bad blocks and parity errors. Bad sectors can form on HDD areas that are not accessed for long periods of time. These problems may lead to unrecoverable data loss. In order to effectively solve the problem and improve data availability disk scrubbing (DS) was developed. DS can scan for bad sectors and/or parity errors in a RAID array. The RAID system reconstructs bad sectors from other sectors and re-assigns it to an undamaged area. At the same time it also detects parity inconsistency; users can decide whether or not to overwrite inconsistent parity. DS is a proactive approach to address data integrity, it maintains the RAID system in a good condition. Unrecoverable data loss As Figure 14 shows, although all of disks, disk #1~4, are online at t=t0, block number D3 is already a bad sector. Even after the rebuild process is completed at t=t3. Data block D1 will not be able to successfully regenerate from the other data and parity blocks. Figure 14- Unrecoverable data 4-1

33 Parity inconsistency Over long periods of time, parity blocks may not be consistent with data blocks. This may result from unexpected power outages or resetting the RAID system before cached data is written to drives. If the parity inconsistency is detected, it indicates a data error exists either on the data disk or parity disk. However, the RAID system can not determine if the error resides on data or parity disks because of the RAID algorithm. Enabling Overwrite Parity in disk scrubbing will automatically correct data on the parity disk whenever parity inconsistency is detected. If the array s parity is seriously damaged, with overwrite parity enabled, data loss may occur after disk scrubbing is completed. Disable it if the parity data has been seriously damaged. Figure 15 describes the detailed flow of disk scrubbing (DS). When DS is running, the controller will read data and parity blocks of a stripe in an array and execute a parity check. DS predicts data block failure and corrects parity errors in order to enhance data integrity and availability. Figure 15 function description of disk scrubbing Note: 1. Disk scrubbing can only be activated when the array is in optimal condition. This means there are no drive member failures in the array and no background task in progress, i.e. array expansion etc. 2. Disk Scrubbing will impact I/O performance; running DS during off peak times is recommended. 3. If the RAID system is powered off while DS is running, it will not resume on the next power up. 4-2

34 Follow the following steps to configure disk scrubbing. Disk Scrubbing Menu Tree Figure 16 Disk Scrubbing Configuration Flow Enabling Overwrite parity option is recommended. Overwrite parity option applies to Disk Scrubbing in both manual and scheduled mode. Manual Scrubbing Follow these steps to manually start and stop disk scrubbing, Step1: Go to Main Menu->Utility->System Utility->Disk Scrubbing and select Manual Scrubbing Step2: Select All arrays or a single array Step3: Select Start or Stop. Once started, the percentage of progress is indicated on the LCD screen. Step4: Repeat the above steps to start or stop scrubbing for other arrays groups. 4-3

35 Scheduled Scrubbing Follow these steps to schedule disk scrubbing. Note: Enable RAID system clock in advance before setting up the schedule scrubbing, or scrubbing will not be able to activate. Refer to section to setup system real time clock (RTC). Step1: Go to Main Menu->Utility->System Utility->Disk Scrubbing and select Schedule Scrubbing Step2: Select all arrays orasinglearray Step3: Select Schedule ON Step4: Select the preferred cycle to run disk scrubbing periodically. For example: Once per 4 weeks Step5: Select the Day of the week, for example: Sat Step6: Manually key in the hour of 24 hour clock, for example: 00 hour Step7: Repeat step1~6 to set up scrubbing schedule for other arrays groups. Disk Scrubbing Report After disk scrubbing is completed, in the output window of hyper terminal, the following information will be displayed. For example: Disk Scrubbing Result: --1. Bad Block Check-- Disk # 1: Found 3 Bad Blocks, Recovered 2, Total 10+(3) Bad Blocks Disk # 2: Found 6 Bad Blocks, Recovered 6, Total 0+(6) Bad Blocks Disk # 3: Found 1 Bad Block, Recovered 1, Total 12+(1) Bad Blocks. Disk # 16:Found 0 Bad Blocks, Recovered 0, Total 19+(0) Bad Blocks --2. Array Parity Check (Overwrite Parity YES) -- Array X: Found 3 Parity Errors, Overwrite Parity Or --2. Array Parity Check (Overwrite Parity NO) -- Array X: Found 3 Parity Errors, Overwrite Parity-NONE Description of Disk Message: Disk # a : Found b Bad Blocks, Recovered c,totalx +(b) BadBlocks a is the disk number, b is the number of bad blocks found during this session of scrubbing, c is the number of bad blocks recovered x is the total number of bad blocks. 4.2 Auto Shutdown RAID system in critical condition Objective The RAID system will be protected against internal overheating condition or UPS AC power 4-4

36 loss. In the RAID system, there are several thermal sensors located on the RAID controller and midplane. If the temperature increased to a dangerous level in the RAID system, it may damage internal components including disk drives. With auto shutdown enabled, if overheating occurred or AC power loss is detected, the RAID system will shutdown after a given time duration. Under the following conditions, auto shutdown will activate automatically if it is enabled. 1. System temperature exceeds threshold 2. All fans failure or not available 3. UPS AC Power Loss Auto shutdown menu tree Note: System real time clock (RTC) must be activated in order for the auto shutdown feature function properly. Follow the steps to set up auto shutdown, Step1: Go to Main Menu->Utility->System Utility->Auto Shutdown->Enable Step2: Select Event Trigger and enable or disable each trigger option. Step3: Select Shutdown duration, for example: 15 min, RAID system will turn off the power automatically after 15 minutes if shutdown event has triggered. Note: 1. If the event triggers are disabled or critical events return to the normal, auto shutdown will be inactivated or canceled. 2. If an auto shutdown event is triggered, the write cache will change from Auto to Write-through mode to ensure data integrity. 4.3 Disk Self Test Check drive healthy in RAID system Objective Disk Self Test (DST) is used to test the health of disks with them installed in the RAID system. Prior to DST a user would have to remove disks individually and run a vendor proprietary disk utility in a separate host computer DST predicts the likelihood of near-term HDD degradation or fault condition. DST performs write test, servo analysis and read scan test on the disks. 4-5

37 Follow the following steps to check disk health condition in RAID system, Disk Self Test menu tree Figure 17 Disk Self Test Configuration Flow Disk Self Test: Step1: Go to Main Menu->Utility->Disk Utility->Disk Self Test Step2: Select Short Self Test andselect All Disks or Disk X tostartdriveselftest Step3: Select Extended Self Test, if there is any error occurrence after short DST (Step2) Then select All Disks or Disk X to further check the suspected drive. Swap the suspected drive if it doesn t pass Extended Self test. Note: 1. Running DST before creating an array is recommended. DST will not overwrite data. 2. DST can only be executed in offline mode. This means that if there is any host activity DST will be terminated and host I/O access will resume. 3. DST can also be performed thru LCD function key directly. Key in password to start short or extended self test of all drives. 4. It may take several hours to run Extended DST depending on the drive capacity and spindle speed. 5. Most newer hard drives support DST, contact your drive vendor to see whether your drives support DST. 4-6

38 4.4 Disk Clone Manually cloning a failing drive Objective Hard drives are the most likely component to fail in a RAID system, and are very difficult to predict when the failure will occur. When a failure does occur the RAID unit will have to regenerate data from the non-failed hard drives to rebuild a new drive, and during this time the RAID system will be in degraded mode. This is where Disk Cloning (DC) can aid a user. Disk Clone can copy a failing drive to a hot spare, and upon completion of cloning, the new cloned disk can take the position of the failing disk immediately or can stand-by until the cloned disk fails. Disk cloning is to help prevent a rebuild from ever occurring and having the unit in degraded mode. There are two options to clone a failing drive: permanent clone and swap after clone. In "permanent clone" mode, the clone disk (hot spare disk) will be the mirror of the source disk until the source disk has failed. The clone disk will then replace the source disk. In "swap after clone" mode, immediately after the clone process is complete the clone disk replaces the source disk and the source disk is taken offline. Disk Clone menu tree Follow the steps to start disk cloning manually, Step1: Go to Main Menu->Utility->Disk Utility->Disk Clone, then select Start Disk Clone Step2: Select Source Disk which is the suspected failing drive in the array. Step3: Select Target Disk and select a target drive. (Clone drive) Note: Only the hot-spare drive will be displayed in target disk. Step4: Select Start Permanent Clone or Start Swap After Clone to start disk clone. After DC is complete, the target disk (clone) status will be marked with a C on the LCD panel. Step5: Repeat these steps to clone other drives. Note: 1.If cloning is in progress, and the source disk fails or goes offline, the cloning disk will replace the source disk and become array s member drive. Also the RAID system will begin rebuilding at the point where cloning stopped. 2. If cloning is in progress, and a member drive fails in an array, excluding the source disk, the cloning will stop and the RAID system will begin rebuilding. 3. Disk clone can only be performed while the array in an optimal condition. 4-7

39 4.5 SMART Predicting a drive failure and automatic disk cloning Objective Disk Clone (DC) is a process of manually cloning data from a source disk to target disk. With the SMART function, the RAID system monitors drive health on preset polling intervals, if hard drive degradation is detected or the user-defined bad sector threshold is reached, the cloning function will begin immediately. SMART Event Trigger There are two SMART event triggers that will begin disk cloning: a SMART failure flag, and a user-defined bad sector threshold. The SMART failure flag is triggered by the drive, and is defined by vendor-specific attributes that may differ model to model. The user-defined bad sector threshold is a specific number of bad sectors per drive. The user must input the bad sector threshold to start disk cloning. SMART Mode There are four modes in SMART function. 1. Disable: SMART function is inactivated. 2. Enable ( Alert Only) : The RAID system monitors using drives SMART on preset time intervals. When a SMART failure is detected, the user will be alerted with a beeper and the drive s status will be changed to a W on the front LCD which indicates a warning 3. Enable ( Permanent Clone) : The RAID system monitors drives SMART, if a SMART failure is detected or user-defined bad sector threshold is reached, disk clone will begin. Upon completion, the clone disk (hot spare disk) will be the mirror of the source disk until the source disk has failed. 4. Enable ( Swap After Clone) : The RAID system monitors drives SMART, if a SMART failure is detected or user-defined bad sector threshold is reached, disk clone will begin. Immediately after cloning has completed, the clone disk (hot spare disk) replaces the source disk and the source disk is taken offline. Follow the following steps to configure SMART function, 4-8

40 SMART menu tree Follow the steps to configure SMART function, Step1: Go to Main Menu->Utility->Disk Utility->SMART, and select Test Disk SMART First, check whether or not your drives support SMART. If your drives don t pass SMART test, drive s status will change to W on the LCD screen. Step2: Go to Bad Sector and decide the value of Threshold for Clone or Threshold for Swap For example: Threshold for Clone: 130, if a drive accumulates 130 bad sectors, disk clone will start. Threshold for Swap: 200, if a drive accumulates 200 bad sectors, the source disk will be taken offline. Step3: Go to Disk Check Time then select a time interval to monitor drive s SMART and bad sector status. For example: 60 minutes Step4: Go to SMART Mode, then select the mode you prefers. Note: 1. Make sure system clock is enabled before configuring SMART function. 2. If bad sector threshold is disabled for Clone and Swap, disk clone will only be activated when drives a SMART failure is detected. 4-9

41 4.6 AV Streaming - Performance-critical streaming application Objective Bad blocks and read or write delays of drives are unavoidable in a RAID system. For AV streaming applications, such as broadcast, post production, video/audio editing application, etc., these errors will cause choppy audio and/or video frame loss. In some instances the entire RAID system will stop operation. Enabling AV Streaming option in the RAID system can eliminate the chance of data transfer delays in a performance-critical streaming application. AV stream option will shorten drive I/O response time, re-arrange cache buffer management for read/write commands and changes the algorithm to read/write data. Only enable the AV Streaming option after it has been tested in a real AV streaming environment by an experienced engineer. AV Streaming menu tree Follow the steps to configure AV Application, Step1: Go to Main Menu->Utility->System Utility->AV Streaming, then select Enable Step2: Go to Disk Timeout and then select a disk I/O timeout value, for example: 3 seconds Note: Once AV streaming option has been enabled and disk timeout has been changed to a low value, the RAID system will frequently alert remapped blocks in the status log. Step3: Go to Remap Threshold and then select a threshold that the RAID system will start to alert remap warning message. Note: 1. AV streaming can only be enabled for a single array configuration. If multiple arrays are present in the RAID system, AV streaming will not work. 2. Single array and single slice is the optimal RAID configuration for AV streaming. Partitioning an array into multiple slices for AV streaming is not recommended. 4-10

42 4.7 PreRead cache - Enhancing sequential read throughput Objective PreRead cache is used to accelerate the performance of applications that access data sequentially, such as film, video, medical imaging and graphic production industries. With PreRead cache enabled, the RAID controller move to cache the next blocks of data that will be needed in the sequence. It reads the data from slow, nonvolatile storage and places it in fast cache memory before it is requested. Only enable PreRead cache after it has been tested in a read-intensive application environment by experienced engineer. PreRead menu tree Follow the steps to configure PreRead function, Step1: Go to Main Menu->Array Params->PreRead Setup, then select Enable Step2: Select Max ReadLog and key in a number, for example: 32 Max Readlog is the record of Read commands that were issued from a host application. Step3: Select Max PreRead thenkeyinanumberforexample:16 Max Preread is the data depth that will be read ahead in advance. Note: If PreRead is not properly setup, it will decrease the I/O performance of the RAID system. 4-11

43 4.8 Alignment Offset Multipath IO S/W (PathGuard) on Window OS Objective Operating systems (OS) reserves private information, known as a signature block, at the beginning of a LUN. The result is an un-alignment of disk striping. As Figure-18 shows, after a physical device is formatted with a file system, a data segment may cross two stripes causing a split I/O command to complete a read or write. Alignment offset is used to set the host logical block address (LBA) alignment with the stripe boundary of a LUN so that it enhances I/O performance of the RAID system. In order to fix this problem and enhance system performance under different operating systems, the LUN should be offsetbasedonitsfilesystemtype. Setting alignment offset is recommended when using PathGuard, easyraid s Multipath I/O software, for Windows operating system. Alignmentoffsetmenutree Figure 18 Alignment Offset Follow the steps to configure alignment offset, Step1: Go to Main Menu->Array Params->Array x->alignment Offset, then select a slice Step2: Select NTFS if the slice will be formatted with Window NT file system Note: 1. Currently, only Microsoft Window NT file system (NTFS) supports the alignment offset function. 2. Alignment offset should be configured before the slice is created. 3. PathGuard is a host-based multipath I/O software for Window 2000/2003 server. Contact technical support team for more information. 4-12

44 Chapter 5 Event Message of RAID system This chapter lists the event message recorded by the RAID system. It contains the following topics: Section 5.1, Event Severity Section 5.2, Event List 5.1 Event Severity Events are classified with different severity levels. 1. Error - Event messages that indicates a significant problem, such as drive/fan/power failure...etc 2. Warning Event messages that are not necessarily significant, but might indicate a possible future problem 3. Information Event messages that describes a successful operation of RAID function. 5.2 Event List 1. Event severity: Error DISK X initial fail, status 0xY! DRAM TEST FAIL Disk X retry SPIN_TIMEOUT Disk X initial SPIN_TIMEOUT ERROR: Disk X Identify Data Error! ERROR: Disk X Inquiry data ERROR! ERROR: Disk parameters ERROR! ERROR: No multi-sector mode! ECC Error Detected at Address 0xX Error: spin IOC_READY timeout Error: No FreeChain. MX OY Host Channel X Init Fail! Issue IOC Fact failed! Issue IOC Init failed! INIT: EnablePost X failed IOC reset failed IOC handle ready state failed INIT: CmdBufferPost failed Disk X initialization failed with status Y DRAM diagnostic test failed Failed to retry operation to disk X within SPIN_TIMEOUT. The disk was offlined. Disk X couldnotbereadywithinspin_timeout.thediskwasofflined. Failed to identify disk X. The disk was offlined. Invalid inquiry data on disk X. The disk was offlined. Invalid Cylinder/Head/Sector disk parameters found. The disk was offlined. Disk did not support multi-sector mode. The disk was offlined. One or more bits error were detected by ECC memory. The faulty address is at X. If there are more than one bit errors, the system hangs and the LCD shows "ECC MultiBit Err". SCSI chip initialization failed. Controller fault. Magic: running out of scatter-gather resource on SCSI Host channel X initialization failed. Controller fault. SCSI chip initialization step failed. Controller fault. SCSI chip initialization step failed. Controller fault. SCSI chip initialization step failed. Controller fault. SCSI chip initialization step failed. Controller fault. SCSI chip initialization step failed. Controller fault. SCSI chip initialization step failed. Controller fault. 5-1