Centera Virtual Pools





Virtual Pools




A virtual pool, or pool, is a logical grouping of data on a Centera cluster. There are three different types of pools:


  • Application Pool: This is a pool bound to one or more application profiles. During the creation of an application profile it is possible to refer to a custom application pool and assign this the home pool. All new data from the application profile will then be written to its home pool. If the application profile has no home pool, the data will be written to the default pool. The default pool is also an application pool and contains every C-Clip on the cluster that is not contained in a custom application pool. Although one application can only have one home pool at a time, it is possible that multiple applications share the same home pool.

  • Cluster Pool: This is a default pool that contains every single C-Clip on the cluster. The cluster pool allows operations across the boundaries of pools using a cluster profile.

  • System Pool: This is a default pool used to store system information. On newly installed Centera clusters there are two system pools: the AuditArchive pool (archiving audit trail information) and the SystemArchive pool (archiving system information). On clusters installed with a CentraStar version older than 4.0.2, there will be an additional system pool: ConsoleArchive, used to store system information related to Centera Console.


Note 1: The system administrator can create, delete, and update custom application pools. The default pool, cluster pool, ConsoleArchive (C* version < 4.0.2), AuditArchive, and SystemArchive pool are built-in and cannot be deleted.


Note 2: Every C-Clip on the cluster belongs to exactly two pools:the cluster pool and the default or a custom application pool. All C-Clips are members of the cluster pool by definition.


Pools provide a solution for:


  • Data Segregation: C-Clips written by one application can be separated from C-Clips written by other applications. Pool membership is determined by the access profile that is used to write a C-Clip. Once a C-Clip is written to a custom application pool, it cannot be moved to another pool. In specific cases C-Clips belonging to the default pool can be moved to a custom application pool but this is discouraged as a general practice. Contact your EMC representative if you want move data from the default pool to a custom application pool.

  • Access Control: Each pool has a pool mask which specifies the operations allowed on the data in the pool. Together with the granted rights or capabilities of an application profile this determines the level of access an application has to the data in a pool.

  • Selective Replication/Restore: Replication and restore operations can be performed on pool level.

  • Selective Query: C-Clips within a specific pool can be queried.

  • Capacity Reporting: Capacity usage can be analyzed and reported on pool level.


Pool Identification


Custom application pools and system pools are identified by a unique ID which cannot be changed. A custom application pool also has a pool name which must be unique on the cluster. Pools with the same name created on different clusters will have different IDs and are not identical.