Posted: 2022-06-02

We have recently identified and confirmed a critical bug found in AhsayCBS / OBM / ACB v9 (v9.1.2.17 to v9.1.4.21) that affects all types of Backup Sets, where source backup data is >32MB, resulting in unrestorable v9 data.

Not affected is restoring data from time period prior to v9.1.2.17 backup dates.

Not affected are Client Agents (OBM, ACB) running v8, or pre-v9.1.2.17.

• Affecting Ahsay v9.1.2.17 up to v9.1.4.21 , issue that affects ANY Backup Set types where source files have raw size greater-than 32MB.
• Example, “tasks.zip” is 40MB, is affected.
• Example, “mylist.txt” is 2MB, is not affected.

• This happens in lookup (find duplicated data) logic in backup of all Backup Set types, regardless if Deduplication is ON or OFF.
• v9 will always find duplicated data from index even Deduplication is OFF. The lookup result will be wrong, hence, the file data is already corrupt.

• Unable to restore due to corrupt backup data

• Ahsay v9.1.2.17 up to v9.1.4.21 , where Deduplication = OFF at any point during backup runs within these versions
• Ahsay v9.1.2.17 up to v9.1.4.21 , where Deduplication = ON and Migrate Data = ENABLED (checkbox marked)
• Ahsay v9.1.2.17 up to v9.1.4.21 , where Deduplication = ON and Migrate Data = DISABLED (checkbox unmarked)

• It is not affected. These source data isn't chunked for Deduplication.

• It depends on the conditions stated above.

• Yes.
• AhsayCBS V9.1.2.0 was the base release version

• Affected are those OBM you applied hotfix v9.1.2.17+ , but not other OBM/ACB running v9.1.2.0

• Pre-v9.1.2.17 data can be restored. Whether pre-v9.1.2.17 can be used depends on whether the backup data of pre-v9.1.2.17 is deleted by Space Free Up routine (Retention cleanup) or not. If pre-v9.1.2.17 data still exists, restoration can be done by revert index.

• No

• Yes, if you enabled AUA for users to upgrade to v9.1.4.0, and it meets the conditions stated above.
• Yes, if you have Agentless (Run on Server) jobs, and it meets the conditions stated above.
• No, if you kept AUA disabled, and users run pre-v9.1.2.17 client.

• Yes, if you enabled AUA for users to upgrade to v9.1.4.0, and it meets the conditions stated above.
• Yes, if you have Agentless (Run on Server) jobs, and it meets the conditions stated above.
• No, if you kept AUA disabled, and users run v8 client, they continue to follow In-File Delta settings.

• No workaround. Data must be backup again after fix is applied.

• Take immediate action to download and install latest release of AhsayCBS v9 and hotfix v9.1.4.22 (or higher) via Ahsay Partner Portal (https://www.ahsay.com/partners). The latest posted hotfix is bundled with Auto Update (AUA) binaries to push the client hotfix to OBM and ACB devices when CBS AUA feature is enabled per user.
• Once required minimum hotfix version is applied, as a one-time routine the next backup job will automatically first run a PDIC [corrected: 2022-06-21] will automatically remove Blocks (BAK) containing backup files that reference invalid checksum file chunks, then reupload source backup file that was corrupted and correctly update the migrate status table. A flag will be set in the Index to denote fix was applied ( likewise reverting the Index to an older copy will retrigger the fix ). [Shared Blocks (BAK), a block containing multiple small source files (valid and corrupt), the BAK is retained until all contents have surpassed validity period, then BAK can be purged by Retention Policy.]
  • Showing when the fix was applied, you can review the next run's backup set log file, for entry “Run to remove backup files referencing dummy checksum file chunks for once…Completed”

• Stop! Do not upgrade until you contact a member our Sales team sales-kb@ahsay.com for assistance with your maintenance renewal.