VI Storage Capacity Planning

Transcription

1 VI Storage Capacity Planning 1.0 Capacity Planning for 1st Tier RAID Storage: Measuring RAID Space Usage and Growth by Dale White RAID space usage can be viewed by opening the My Computer icon on the cluster node that is currently holding the cluster. If you have it set to show detail views, you will be able to see how large the drive is, and how much free space is available. For more detail, right-click on each drive and choose Properties. Measuring the daily/weekly/monthly growth rate of your Imaging files is accomplished through a couple of fairly simple methods. One of the easiest ways is to review the nightly incremental backups. The incremental backups only catch the new files that were written that day, so if you look at your history of nightly backups, you may see numbers like 5GB, 10GB, 11GB, 4GB, and 13GB. Simply add those numbers together to calculate the weekly growth rate for a particular week. If your site maintains a long history of recent backups, you can calculate a monthly growth rate from a larger data set. One other method for measuring your growth rate is to simply count the number of jukebox platters you use each day (assuming you re not a Spoke site on VISNs with centralized jukeboxes). If you are filling one 30GB Ultra Density Optical (UDO) platter a day, it s pretty easy to calculate that you are generating 150GB of data a week; multiplying that times 4 means you re doing 600GB a month, and times 12 means 7.2TB a year. When talking about capacity planning, the generic recommendation is to have five years worth of data online. This means if a doctor at your medical center asks for any image in the last five years, it would be found on RAID and not on the jukebox. Using a medium-size site as an example, that would mean 7.2TB times 5 years, equating to roughly 36TB of RAID space needed to meet the generic recommendation. One of the main variables you have to also factor in to that equation is whether you re getting any new devices in that time frame. Many of the newer CT devices, for example, could increase your daily storage needs by 10 15%. If you re site is getting a refresh of modalities, you could see your daily/weekly/monthly storage usage double.

2 For sites that have jukeboxes running with DiskXtender, you can also get an idea of whether your RAID is big enough by looking at your extended drives. At the bottom of the right window pane when you choose an extended drive is some basic information, including Files Moved, Files Fetched, Files Purged (from the extended drive), and Pending Move Files; the information you re interested in is Files Fetched. On sites with too little RAID space, it s not uncommon to see 30,000 50,000 file fetches a week. On sites with plenty of RAID space, there would be zero or maybe only a few hundred file fetches per month.

3 2.0 Capacity Planning for Archive Storage by JC LaRue This section provides an overview of the process for successful capacity planning with the Archive Appliance (AA) product. Additional information, including user guides, administrator guides and online training can be found at this location: AA System and UDO Media Management Summary The AA products installed at the VA sites include the following components: Quantity one (1) A12 Plasmon RAID array consisting of eight (8) Serial ATA (SATA) HDDs. Five (5) SATA HDDs are in a RAID-5 configuration and serve as the repository for incoming files/studies/data. This RAID space is segmented into 100G volumes, one volume/share for each site that requires write space on the archive. Two (2) SATA HDDs are in a RAID-1 configuration and serve as the system RAID for storing and managing the OS and internal system functions. One (1) SATA HDD serves as the global hot spare. Quantity one (1) or two (2) Plasmon G-Series Libraries with 238 to 1276 media slots and total of four (4) to twelve (12) UDO60 drives. Quantity one (1) copy of hierarchical storage management (HSM) software called SSM (Storage Space Manager). SSM software is responsible for managing the file system, migrating data from the RAID array to UDO media, and deleting migrated files and replacing them with inodes/pointers. Incoming Data The background processor writes new, incoming data to the 100G network share configured on the AA RAID array. SSM is responsible for migrating new, incoming files from the AA RAID array to two (2) separate pools that consist of UDO media. One copy of the data is written to the primary pool and another copy is written to the secondary pool. Once a file has successfully moved to the UDO media in both pools, SSM deletes the file from the RAID and writes a pointer/inode to the RAID which references the file location on UDO media.

4 2.2 Capacity Monitoring There are two specific areas to monitor in the AA GUI with regards to capacity: the Online Media page and the Archive tab of the Volumes page. 1. Online Media page (Navigate to Storage > Online Media) a. Spare = Blank media available for writing. When the number of spare media drops below five (5), the AA will send an notice to the users configured on the GUI page under System > Notification. It is important to maintain five or more spare media for each configured volume to ensure available write space. b. Open = Media currently being written to (in use). Each configured volume will have two (2) pieces of open media for writing new files. One piece of media is called the primary copy and the second piece of media is called the secondary copy. Media will remain in an open state until the media fills with data and is closed. c. Closed = Media that is full and will no longer be written to. The value for closed media reflects the total number of primary and secondary copies. d. Backup = Media dedicated to the daily file system backup operation. NOTE: When the total amount of data archived exceeds 16 Terabytes or over 50 million files, the backup media no longer has the capacity to store the daily backup. At this time, it will be necessary to configure the AA backup operation to write to an external network share/drive. e. Empty Slots = the number of empty slots available for UDO media.

5 2. Volume Archive tab of the Volumes page: (Navigate to Storage > Volumes > [select volume] > Archive (tab) a. Total Data Archived reflects the total amount of data stored on this specific volume. b. Available to offline reflects the number of UDO media that can be removed from the AA. HP recommends that the Primary copies remain in the library for future file access. The Secondary copies should be removed from the AA and stored in a remote/secure location. NOTE: When the AA becomes fully populated with primary media, primary copies can be removed to make room for blank (new/spare) media. In this case, the user requests removal of the primary copies and the AA exports those copies in the order of least recently used to ensure more recent data remains online and available.

6 2.3 Capacity Planning Capacity planning requires the user to log into the AA GUI on a regular basis. The specific GUI pages to monitor are Online Media and the Archive tab for each specific volume. Typical users are asking the following questions: How many pieces of spare UDO media are left in the AA? How quickly is the AA consuming UDO media? How much longer before I run out of spare UDO media? How many slots do I have left in the AA? How many pieces of secondary UDO media are ready to be removed so I can have access to more slots? Effective capacity planning requires the user to track the following information: 1. The number of UDO media consumed on a weekly or monthly basis. Confirm the media consumption rate and the rate at which slots are being consumed. 2. The number of secondary media to be taken offline. Removing secondary media will free up slots for more media to be inserted. Secondary media should be stored in a remote location to facilitate disaster recovery. 3. The number of available slots. Based on the number of media consumed on a weekly/monthly basis, the user can make a rough estimate of when all AA slots will be occupied by primary media. When all slots have been consumed, the user begins the practice of removing both the primary and secondary copies of UDO media.

7 NOTE: When removing primary copies, the AA ejects the oldest media first to ensure that the most recently accessed data is online and available. If the AA receives a request for a file that is on a piece of UDO media that is not in the library, the AA will send an to the users configured on the GUI page at System > Notification. The message includes the barcode information for the specific piece of media required to fulfill the file request. This information is also posted to the GUI page under Storage > Media Requests.