Chapter 2: Service Menus
Blockpool Verify and Blockpool Corruption Actions
Quantum DXi6900-S Field Service Manual
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cluster, which could indicate bit rot. The corruption message indicates that one or more blocklets are
corrupted in a cluster. There may be multiple clusters containing corrupted blocklets, in which case you
will see multiple messages.
Detecting Blob Corruption
If blocklet corruptions are detected, you must find out which BLOBs (if any) are affected by these corrupted
blocklets.
1. At the command prompt type:
/hurricane/blockpool/bin/blockpool Dblob_datNlocal@localhost &
Note:
Due to the lengthy completion time, it is recommended that this operation be run with a
nohup command. This will prevent a subsequent logout from stopping the operation.
This operation takes some time to complete, but it can be done in parallel with other operations. For
example, if you've stored 100TB into the blockpool, even if that has reduced to 10TB, the operation will still
take approximately = 3 days to verify if the system is idle.
The result of this BLOB data verify will be messages in the following form:
BLOB <tag> is corrupt. <explanation>
These individual BLOB tags can then be mapped back to VTL carts or NAS files (using deduputil). These
carts or files are not able to be retrieved (or replicated) until repaired, however they can be deleted.
If you see no corrupt BLOB messages (but you did see corrupt blocklet messages), the corrupt blocklets are
orphaned. For example, they are not referenced by any BLOBs. In this case, there is nothing to do, it is safe
to leave them in the blockpool.
Note:
Blocklets become orphaned either due to rare cases with an unclean shutdown recovery or as
the result of a delete operation that has been run, but no compaction operation has been run yet (the
latter is not possible pre 1.1).
Repairing a Blocklet Corruption
In order to repair corrupted blocklets, the blockpool must re-ingest the data. This can be achieved by storing
the fragment files again, if they are un-truncated, or by asking the customer to re-store their backup from
tape. In some cases, just storing a new (similar) backup could repair the damage.
Verifying the Repair of Blocklet Corruption
The blockpool will display messages when it repairs blocklets. However, to prove that all of the corruption
has been repaired, a second blockpool verification script must be run. If it shows no corruption messages,
the blockpool corruption is repaired. If messages are still displayed, repeat the process, and ingest different
data to repair.
