Data Storage Solutions

Transcription

1 Data Storage Solutions Module EMC Corporation. All rights reserved. Data Storage Solutions - 1

2 Data Storage Solutions Upon completion of this module, you will be able to: List the common storage media and solutions. Describe the three common storage environments EMC Corporation. All rights reserved. Data Storage Solutions - 2 Large amounts of data can be stored on hard disks, tapes, and optical disks. Each of these media provides solutions that address specific data storage and retrieval needs. Networked storage comprised of disk arrays and networking components has become the dominant solution for most business data storage needs. In this module, we will look at each of these alternatives with a detailed look at the disk systems and interconnects. Data Storage Solutions - 2

3 Lesson: Storage Solution Alternatives Upon completion of this lesson, you will be able to: Describe the different media and solutions available to address data storage needs of a business. Describe the role of each solution in the overall data storage needs. Describe the advantages of disk arrays EMC Corporation. All rights reserved. Data Storage Solutions - 3 Internal or external to the server, the options available for storing data are Tape Optical Disks Hard Disks This lesson reviews the various storage media options and discusses the potential uses for each. Data Storage Solutions - 3

4 Common Data Storage Media Tape Library: A collection of tape drives and tapes Jukeboxes: A collection of optical disks and drives Disk Arrays: A collection hard disks Each solution addresses specific needs for data storage and management. Tape Library Backup/Restore; Archival of data Jukeboxes Typically to store non-changing content over long periods of time Disk Arrays To store data that has to be immediately accessible and on-line 2006 EMC Corporation. All rights reserved. Data Storage Solutions - 4 In the early days of hard disk evolution, tapes provided the primary means of data storage. We have all perhaps seen pictures of computer centers with several tape drives stacked in a row with reels of tapes, and operators busy mounting/unmounting these reels. From being primary data storage solutions, tapes can now be regarded as secondary storage. As the need for storing large amount of data grows, each of these can be combined and housed in central units. Data Storage Solutions - 4

5 Tape Storage Systems Tape based storage is relatively inexpensive, compared to disk arrays. They served as primary storage solutions in the early days. Tape drives use Read/Write heads to record bits of data onto magnetic material on the tape surface. This technology continues to evolve, providing higher storage capacity, greater reliability, and improved performance EMC Corporation. All rights reserved. Data Storage Solutions - 5 One of the alternatives for storing the large amounts of data found in a typical business is to use magnetic tape. The data is stored on a thin polyester tape coated with magnetic particles. This medium has been used for data storage for over 50 years and has evolved from bulky reel-to-reel systems to smaller, compact cassette (or cartridge) based storage systems with automatic loaders and storage racks. While the formats have changed over time to allow for more data per reel and faster transfers rates, the basic uses of tape systems have remained remarkably constant. Modern tape libraries or silos can have thousands of cartridges and robotics to locate, load, and unload tapes into different drive units in the same frame. Data Storage Solutions - 5

6 Storing Data on Tape Data is recorded sequentially from the beginning to end, one byte after another. Because data is stored linearly along the length of the tape, random access to specific bits of data is slow and time consuming. This severely limits tape as a medium for real-time, rapid access to data. Tapes cannot be shared among multiple users or applications EMC Corporation. All rights reserved. Data Storage Solutions - 6 Access to, and manipulation of data on tape can be a time consuming process. As data is stored sequentially on tape, random access is not possible. In order to access a file on tape, the tape drive has to wind or rewind it to locate the file. Then the information is read into the computer s memory. This process takes time. Typically tapes can perform reasonably well if the entire contents from start to finish has to be read from them and written to another location such as a hard disk. This makes them a prevalent low cost solution for backup and archival of data. It is interesting to note that prior to availability of CD-ROM, many vendors of Operating Systems and applications used to ship the software on tape cartridges. Data Storage Solutions - 6

7 Optical Data Storage Popular in small, single-user computing environments. Frequently used by individuals to store and share data, or as backup solution. Also used as distribution medium for applications, or as a means of transferring small amounts of data from one self-contained system to another EMC Corporation. All rights reserved. Data Storage Solutions - 7 With the emergence of Optical Disks came the advantage of write-protected data and random access. Large quantities of these disks were assembled into optical jukeboxes, solutions that provided relatively large capacity arrays of this media for centralized network-accessible storage. A single optical disk is still far lower in capacity than a tape or hard disks. Data Storage Solutions - 7

8 Disk Based Storage From a historical perspective, we will explore the following disk based storage solutions: DASD: Direct Access Storage Device JBOD: Just a Bunch Of Disks Disk Arrays Intelligent Disk Arrays 2006 EMC Corporation. All rights reserved. Data Storage Solutions - 8 Disk drives, since their inception, have been the preferred media for storing data. The growth of data demanded larger and larger capacities of these drives leading to the media storage array. An array is capable of serving data to multiple severs concurrently. As data storage needs started exceeding the capacities of individual drives, solutions emerged to make a collection of drives available to either a single server or multiple servers. The components of the modern arrays with built-in intelligence will be discussed in Section 2. Data Storage Solutions - 8

9 Types of Disk Systems: DASD Mainframe Introduced by IBM in Disk The oldest of the techniques for accessing disks from a host computer. Disks are accessed directly by a single host, historically a mainframe system EMC Corporation. All rights reserved. Data Storage Solutions - 9 DASD Direct Access Storage Device (Originally introduced by IBM in 1956) is the oldest of the techniques for accessing disks from a host computer. Disks are directly accessed from the host (historically a mainframe system) and tightly coupled to the host environment. A hard drive in a personal computer is an example of a DASD system. Typically one can view the DASD as a oneto-one relationship between a server/computer and its disk drive. All access to the data on the disk has to be routed through the server/computer. Prior to the advent of networking technologies, such routing involved submission of a job request to the operators. Whereas the server/computer had direct access to data, the individual did not. In addition to the inconvenience of locating and loading the correct reels/cartridges of tape, DASD disk packs had to be swapped in and out for specific job runs. Despite their slowness, they did offer a faster alternative than tapes. If a disk in the pack failed, all data was lost or at the very least was suspect. Data Storage Solutions - 9

10 Types of Disk Systems: JBOD Multiple physical disks in an external cabinet. Host Array connects to a single server only. Provides higher storage capacity with increased number of drives. Data not protected by JBOD Disk Disk Disk Disk Disk Array 2006 EMC Corporation. All rights reserved. Data Storage Solutions - 10 JBOD is an acronym for just a bunch of disks. The drives in a JBOD array can be independently addressed and accessed by the Server. Data Storage Solutions - 10

11 Types of Disk Systems: Disk Arrays Array controllers for optimized I/O operations and RAID calculations. Host A Host B Host C Higher speed interconnects between drives than JBODs. Multiple host I/O channels. Can be partitioned to allow each host to access its own set of drives. Disk Array Controller Disk 1 Disk 2 Disk 3 Disk 4 Disk 5 Host A Host B Host C 2006 EMC Corporation. All rights reserved. Data Storage Solutions - 11 Disk arrays extend the concept of JBODs by improving performance and reliability. They have multiple host I/O ports. This enables connecting multiple hosts to the same disk array. Array management software allows the partitioning or segregation of array resources, so that a disk or group of disks can be allocated to each of the hosts. Typically they have controllers that can perform RAID (Redundant Array of Independent Disks) calculations. Data Storage Solutions - 11

12 Types of Disk Systems: Intelligent Disk Arrays Highly optimized for I/O processing. Cache for improving I/O performance. Operating environments provide: Intelligence for managing Cache, Array resource allocation, Host access to Array resources, Connectivity for heterogeneous Hosts Host A Host B Host C Disk Array Controller Disk 1 Disk 2 Disk 3 Disk 4 Disk EMC Corporation. All rights reserved. Data Storage Solutions - 12 Intelligent Disk Arrays have an operating environment. This can be viewed as an operating system for the array. They also have large amounts of Cache. Sophisticated algorithms manage Cache to optimize the read/write requests from the Hosts. Large capacity drives can be partitioned or sliced into smaller units. These smaller units in turn can be presented to Hosts as individual disk drives. Array management software can also enable multiple hosts to access the array via the same I/O channel. The operating environment ensures that each host can only access the disk resources allocated to it. Data Storage Solutions - 12

13 Lesson: Summary Topics covered in this lesson included: Tape Optical Disks DASD JBOD Disk Arrays Intelligent Disk Arrays 2006 EMC Corporation. All rights reserved. Data Storage Solutions - 13 In this lesson, we reviewed the different data storage media options of: Tapes Inexpensive solution (compared to disk) Often used for backup and recovery Optical - Mostly used by individuals Disk DASD the oldest and most traditional disk system JBOD a collection of disks Arrays an organized collection of disks Intelligent Arrays a sophisticated, optimized collection of disks Data Storage Solutions - 13

14 Lesson: Storage Environment Upon completion of this lesson, you will be able to: Describe Direct Attached Storage (DAS) features. Describe Storage Area Network (SAN) features. Describe Network Attached Storage (NAS) features EMC Corporation. All rights reserved. Data Storage Solutions - 14 There are different types of Storage Environments: DAS Direct Attached Storage Networked Storage: Storage Area Network SAN Network Attached Storage NAS Data Storage Solutions - 14

15 Direct Attached Storage DAS Client 1 Server A Application A Disks for Server A Local Area Client 2 Network Server B Application B Disks for Server B Disks for Server C Client 3 Server C Application C 2006 EMC Corporation. All rights reserved. Data Storage Solutions - 15 In a Direct Attached Storage (DAS) environment, servers connect directly to the disk array typically via a SCSI interface. The same connectivity port on the Disk array cannot be shared between multiple servers. Clients connect to the Servers through the Local Area Network The distance between the Server and the Disk array is governed by the SCSI limitations. With the advent of Storage Area Networks and Fibre Channel interface, this method of Disk array access is becoming less prevalent. Data Storage Solutions - 15

16 Network Attached Storage NAS Server A File System A Client 1 NAS Device A File System A Disks for File System A Client 2 Local Area Network Internal/External connectivity to disks or arrays NAS Device B File System B Disks for File System B Client 3 Server B File System B 2006 EMC Corporation. All rights reserved. Data Storage Solutions - 16 In a Network Attached Storage (NAS) environment, NAS Devices access the disks in an array via direct connection or through external connectivity. The NAS heads are optimized for file serving. They are setup to export/share file systems. Servers called NAS clients access these file systems over the Local Area Network (LAN) to run applications. The clients connect to these servers also over the LAN. Data Storage Solutions - 16

17 Storage Area Network SAN Client 1 Server A Application A Disks for Server A Client 2 Local Area Network Server B Application B SAN Disks for Server B Disks for Server C Client 3 Server C Application C Disk Array 2006 EMC Corporation. All rights reserved. Data Storage Solutions - 17 In a Storage Area Network (SAN) environment, servers access the disk array through a dedicated network designated as SAN in the slide. SAN consists of Fibre Channel switches that provide connectivity between the servers and the disk array. In this model, multiple servers can access the same Fibre Channel port on the disk array. The distance between the server and the disk array can also be greater than that permitted in a direct attached SCSI environment. Clients communicate with the servers over the Local Area Network (LAN). Data Storage Solutions - 17

18 Lesson: Summary Topics covered in this lesson included: Direct Attached Storage (DAS) features. Network Attached Storage (NAS) features. Storage Area Network (SAN) features EMC Corporation. All rights reserved. Data Storage Solutions - 18 In this lesson we looked at the different models for connecting storage devices including: Direct Attached Storage (DAS) a single computer connection Network Attached Storage (NAS) for multiple (possibly different OS) hosts and file system data Storage Area Networks (SAN) high speed channel, with multiple hosts, and an intelligent storage controller. Data Storage Solutions - 18

19 Module Summary Key points covered in this module: The three types of data storage media. The three storage environments EMC Corporation. All rights reserved. Data Storage Solutions - 19 This module described The three common data storage media types include: Tapes Optical disks Hard disks The four common hard disk systems include: DASD JBOD Array Intelligent Arrays The three models used to connect disks to computers include: DAS NAS SAN Data Storage Solutions - 19

20 Check Your Knowledge What are the three most common storage media? What are the three types of disk-based solutions? What are the advantages of a disk-based storage solution? What are the three storage environments? 2006 EMC Corporation. All rights reserved. Data Storage Solutions - 20 Data Storage Solutions - 20