Context

Tool mentors explain how a tool can perform tasks, which are part of ITUP processes and activities. The tasks are listed as Related Elements in the Relationships section.

You can see the details of how processes and activities are supported by this tool mentor, by clicking the links next to the icons:

•   IT Service Continuity Management
  •   Prepare IT Service Continuity Capability

Details

IT Service Continuity Management is concerned with managing the ability of an organization to continue to provide a pre-determined and agreed level of IT services to support the minimum business requirements, following an interruption to the business. The ITUP mentor named "How to Use TSM to Create and Maintain IT Service Continuity Plan" provides information on creating and maintaining the plan. This section assumes that the plan has been created and that now certain procedures must be followed with IBM® Tivoli® Storage Manager on a daily basis to ensure that if the need arises to execute a recovery, that recovery will work properly.

As part of creating the plan, information is gathered about the Service Level Agreements (SLAs) and Quality of Service (QOS) that Tivoli Storage Manager will provide to meet business requirements and to provide the best match for the level of protection and availability for the data in relation to the business value of the data. As part of the planning process, Tivoli Storage Manager policy has been designed and implemented to provide the required QOS.

In the case of Tivoli Storage Manager, the preparation required to support an eventual recovery involves ensuring that data from all sources is scheduled for backup as reflected by the recovery point objectives (RPO) in the SLA and that it is stored on media in such a way that Tivoli Storage Manager will be able to handle media contention and throughput to restore the data as specified in the recover time objectives (RTO) of the SLA. For example, if one day's worth of data loss is an acceptable risk, then a daily scheduled backup would be sufficient. If only one hour's worth of data loss is acceptable, then the backup schedule for that data should be hourly. Tivoli Storage Manager supports flexible calendar-based scheduling, which can handle any RPO scenario and the architecture designed as part of the planning process ensures that throughput requirements have been considered to ensure that the amount of data that needs to be stored in a scheduled backup window or restored to meet RTO can be met.

Tivoli Storage Manager policy provides ways to not only specify the number of versions and retention period for data it can also direct different types of data to different types of media such as disk and tape. It can also control how data is stored on media. For example, during a backup, Tivoli Storage Manager can pick any tape with available space and store data on it. Over time, the data originating from a certain computer might be spread out over hundreds of tapes. Because tape location and mounting takes time and because data from other computers might be stored on the same tape as another, it could take a long time to restore because of contention for tapes and because many tape mounts and seeks might be required to get all the pieces of data that are needed to complete a restore. Tivoli Storage Manager provides options that allow restore processes to be optimized with a key option being called collocation . Collocation is a way to ensure that the data from a specific file system, computer, or group of computers is stored on a minimum set of volumes. Collocation groups are especially useful when high-capacity tape technology such as LTO-3 is used with computers (also referred to as nodes) or applications with relatively small data stores. Because in this case each tape can store 400 to 800GB of data, it would be inefficient to have only one node back up its data to a tape as would be the case for collocation by node. Collocation groups allow you to specify that the data that belongs to a group of nodes should be stored on a minimal set of volumes. The other advantage this method has is that during a restore Tivoli Storage Manager can mount multiple volumes to perform parallel data movement using what is called a multi-session restore. For this method to work, the data must be stored on multiple volumes. Using collocation groups will ensure that tape capacity is efficiently used because multiple nodes can fill up a tape. It will also ensure that there will be a minimal number of tape mounts, which increase restore performance, and because data is likely to be spread across a small number of volumes, it will ensure that those volumes can be mounted in parallel to support multi-session restores, which further improve restore time.

Tivoli Storage Manager schedules must be run to ensure that data is backed up, that RPOs can be met, and that policy must be configured to ensure that data is stored on media in a way that ensures RTO can be met. The planning process needed to consider setting up Tivoli Storage Manager to store data in storage pools and storing information about the data (metadata) in its database. In order to support disaster recovery, Tivoli Storage Manager storage pools and database must also be backed up and taken off-site and Tivoli Storage Manager provides a disaster recovery manager (DRM) feature that will help. Tivoli Storage Manager also requires that a certain number of housekeeping processes be run each day to ensure that old data is expired and reclaimed and that data moves from one storage pool to another within the overall Tivoli Storage Manager storage hierarchy.

Part of the preparation to ensure recovery is to ensure that DRM and the other housekeeping chores are done on a regular basis. In addition to node scheduling, Tivoli Storage Manager also provides scheduling for administrative functions. The types and ordering of these processes is well documented making it easy to ensure that Tivoli Storage Manager will continue to run smoothly and effectively.

As soon as the node and administrative schedules are running and data is being backed up and stored on the appropriate media, you are prepared in case there is a need to perform restoration of any of the protected data.

Another critical step that must be taken to ensure that recovery is possible is to periodically exercise the restore processes. The worst time to find out that the restore processes won't work because of incorrect preparation is when you absolutely need to restore. By periodically performing various types of restores, you will help ensure that the preparation is correct and that data can be restored when needed.

For more information, refer to:

http://publib.boulder.ibm.com/infocenter/tivihelp/index.jsp?toc=/com.ibm.itstorage.doc/toc.xml

At this site, search for:

• "Policy Configuration Scenarios"
• "Managing Storage Pools and Volumes"
• "Using Disaster Recovery Manager"

The following IBM Redbooks and papers also provide useful and related information:

http://www.redbooks.ibm.com/cgi-bin/searchsite.cgi?query=sg24-6844

For More Information

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