IBM Tivoli Storage Manager, Version 7.1

Simultaneous-write operation in a simple migration scenario

In this example, the storage pool hierarchy contains two primary storage pools. The next storage pool has two copy storage pools defined. A copy of one of the files to be migrated to the next storage pool exists in one of the copy storage pools.

FILEPOOL and TAPEPOOL are defined in your storage pool hierarchy. Two copy storage pools, COPYPOOL1 and COPYPOOL2, are defined to TAPEPOOL. Files A, B, and C are in FILEPOOL and eligible to be migrated. A copy of file C exists in COPYPOOL2.

The storage pool hierarchy and the copy storage pools that are associated with TAPEPOOL are displayed in Figure 1.

Figure 1. A storage pool hierarchy with files eligible to be migrated

There are two primary storage pools. FILEPOOL is the destination primary storage pool. TAPEPOOL is the next storage pool in the storage pool hierarchy. Files A, B, and C are in FILEPOOL. A copy of file C exists in one of the two copy storage pools, COPYPOOL1.

To specify simultaneous-write operations only during migration, issue the following command for TAPEPOOL:

update stgpool tapepool autocopy=migration

Tip: In this example, the setting of the AUTOCOPY parameter for FILEPOOL is not relevant. TAPEPOOL is the target of the data migration.

When files A, B and C are migrated, the following events occur:

Files A and B are simultaneously written to TAPEPOOL, COPYPOOL1 and COPYPOOL2.
File C is simultaneously written to TAPEPOOL and COPYPOOL2. File C is not written to COPYPOOL1 because COPYPOOL1 has a copy of the file.

See Figure 2.

Figure 2. Simultaneous-write operation during migration to two copy storage pools

Files A, B, and C are migrated to TAPEPOOL and simultaneously written to COPYPOOL2. Only files A and B are simultaneously written to COPYPOOL1.

As a precaution, issue the BACKUP STGPOOL and COPY ACTIVEDATA commands after the migration operation has completed. Data that is simultaneously written to copy storage pools or active-data pools during migration is not copied when primary storage pools are backed up or when active data is copied.

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