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Invalid hash found during a full integrity check

Article ID: 241
Last updated: 28 Nov, 2013

Symptom

When performing a full Integity Check , some files are reported as having invalid hashes e.g.:
Error: Group\BAckup_Account - Invalid SHA-256 data hash for patch file ad\94..... expected but 0b154.... found

Cause

When a Streaming Backup connection was dropped due to communications issues and the backup client retried the backup, the file that was being backed up during the connection drop would have been stored on the SP with an incorrect hash. Even though the file had an incorrect hash reference the data was still correct and restorable at that point. However, manually running a Full IC at that point would have detected this invalid hash and reported it as data corruption, deleting the file and any dependencies in the process. If no IC was run the affected file will however be restored without error, and rolling up to any patches that were dependent on the file would also result in valid data.

The bug in the backup client has been fixed in V7.0.3 so that connection issues will no longer result in invalid hashes on the SP.

Also added in the V7.0.3 StorageServer are two new settings:

  • VerifyHashesDuringRollUp
    Enabled by default, this setting determines whether the hashes of files should be verified as part of the roll-up process.
  • QueueFullICAfterRollUpHashMismatch
    Enabled by default, this setting determines whether a Full Integrity Check will be queued if the roll-up detects an invalid hash (as part of the hash checking option detailed above).
    Note that the Full IC will delete files with these invalid hashes, as well as any other files that depend on them. The backup client will then send the latest version of the file in question during the next backup (in full, not patched).

Solution

This issue is resolved in V7.0.3 Storage Platform.
Logon to the Attix5 Partner Area or contact your Reseller to download V7.0.3.

Article ID: 241
Last updated: 28 Nov, 2013
Revision: 4
Views: 4572
Comments: 0
Posted: 28 Nov, 2013 by Van Rensburg J.
Updated: 28 Nov, 2013 by Van Rensburg J.
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