During concurrent media changes on two separate deduplication devices on the same media server, using the Deduplication Option (Dedupe), the data on one of the devices could be inadvertently corrupted.

Article:TECH125840  |  Created: 2010-01-08  |  Updated: 2011-10-12  |  Article URL http://www.symantec.com/docs/TECH125840
Article Type
Technical Solution


Issue



During concurrent media changes on two separate deduplication devices on the same media server, using the Deduplication Option (Dedupe), the data on one of the devices could be inadvertently corrupted.


Cause



The issue maybe encountered when two jobs were running on the same media server, and were concurrently transferring data from one Deduplication device to another.  However it was also found that if two jobs  on one media server were running concurrently from any source to two separate Deduplication devices the same condition could be met that would cause the write operation to truncate data on one of the Deduplication devices.

In both scenarios the corruptions happens when both of the Deduplication devices attempt to mount media at the same time.

Here are the requirements for this situation to occur:
 
1. There must be two deduplication devices actively in-use on the same media server.  The types of deduplication devices include any combination of:
 
a. One or more Deduplication Storage Folders
 
b. One or more supported OST/deduplication hardware appliances. Example: PureDisk, DataDomain or ExaGrid
 
2. The two deduplication devices must be changing media at the same time.  The media change operation happens by default every 50 GB or when a new job starts that uses an OST device.

The problem could occasionally occur when two separate deduplication devices are in use on the same media server.  During concurrent media changes on the separate deduplication devices the data on one of the devices could be inadvertently deleted.


Solution



The above mentioned issue has been fixed by way of a hotfix. Please refer the Related Articles section below for more information.

This issue is resolved in Backup Exec 2010 revision 2896 Hotfix 345316.

For 32bit systems:    www.symantec.com/docs/TECH125819
For 64bit systems:    www.symantec.com/docs/TECH125816 

Woraround:
The issue can be avoided by not allowing two deduplication devices active at same time on the same media server.

Supplemental Materials

SourceETrack
Value1951977
Description

If two opt-dupe jobs are running concurrently, the source media may become corrupted



Legacy ID



345611


Article URL http://www.symantec.com/docs/TECH125840


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