IBM Support

CRC data in server storage pools

Troubleshooting


Problem

CRC generation if CRCDATA is enabled for a storage pool.

Cause

Information for the Cyclic Redundancy Check comparison can only be generated when the data is first stored on the Tivoli Storage Manager Server.

Resolving The Problem

Storage pool CRC data is only created when data is originally written to the initial storage pool upon data backup/archive. This is the only point at which the Tivoli Storage Manager/IBM Spectrum Protect server evaluates the internal characteristics of the data. Processes such as migration, move data, copy storage pool, or reclamation are only "copy" operations so CRC data cannot be created and added at this time.

This means that if the initial storage pool the data is written to does not have CRCDATA enabled the data will not be stored with CRC data. Even if the next pool or copy pool has CRCDATA enabled CRC data will not be created as the data is "copied" to these pools.

This also means that data already stored in a storage pool will not have CRC data generated for it if CRCDATA is updated from no to yes. Only new data written to the pool (still assuming it is the first pool the data is written too) will have CRC data generated for it.

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Product Synonym

TSM

Document Information

Modified date:
17 June 2018

UID

swg21104372