IBM TSM FastBack: Potential Data Corruption When a Snapshot and Cleanup Task Run on the Same Volume Simultaneously
IBM Tivoli Storage Manager (TSM) FastBack backup data may become corrupted when a snapshot is started on a volume at the same time the Cleanup task is working on the backup chain which contains the same volume. A fix is available.
If a snapshot is started while cleanup is running on the same backup chain, the FastBack Server suspends the cleanup task and resumes it when the snapshot is finished. Due to the issue reported by APAR IC84887, the FastBack Server may use incorrect metadata for the snapshot once it resumes. The data from the paused cleanup task, instead of the metadata, can be used for completion of the snapshot and the backup chain can become corrupted.
Tivoli Storage Manager FastBack version 5.5.x and versions 6.1.0 through 6.1.6.
How to Determine Whether your Environment is Affected:
Check the FB Server logs for the following repeating pattern:
[MMM DD HH:MM:SS:TTT](ebc)->I4.LIB : CDBAccess::LockRecord: GetRecord failed for Record XXXX
[MMM DD HH:MM:SS:TTT](ebc)->I4.GENERAL : JOB_LOCATION_LIST_S_GetJobLocationsString_FBDB:Failed FBDB_ACCESS_S_LockJob on Job [XXXX]
[MMM DD HH:MM:SS:TTT](ebc)->I4.GENERAL :JOB_LOCATION_LIST_S_GetJobLocationsString:Failed JOB_LOCATION_LIST_S_GetJobLocationsString_FBDB on Job [XXXX]
[MMM DD HH:MM:SS:TTT](ebc)--->E18.LIB :VolumeControl::get_lut_from_cache: LUTCache::get_lut failed for mega block 23 (job XXXX)
[MMM DD HH:MM:SS:TTT](ebc)--->E18.LIB :VolumeControl::get_blocks: get_lut_from_cache failed for megablock NN (job YYYY)
[MMM DD HH:MM:SS:TTT](ebc)--->E18.LIB :VolumeControlManager::get_block: VolumeControl::get_blockfailed,id = 'Path: 'REP:/' Job: YYYY'
[MMM DD HH:MM:SS:TTT](ebc)->I4.GENERAL :DM_S_DifferentialReadPreCalculatedCRCValue:VCMLIB_S_GetBlockControlData failed
If all of these messages are found, you are affected.
Take a full snapshot of the affected chain, delete the previous snapshots of the chain, and apply the fix by installing FastBack 184.108.40.206 or higher
Availability of Fixes:
|Release||Affected levels||First level that includes the fix|
|Tivoli Storage Manager FastBack 6.1||220.127.116.11 through 18.104.22.168||Version 22.214.171.124
Available in Fix Central
|Tivoli Storage Manager FastBack 5.5||All 5.5 levels||Customers that use FastBack version 5.5.x need to upgrade to FastBack version 126.96.36.199 or higher to fix this issue|