When duplicating images to a PDDO storage pool, if duplication fails initially but succeeds on a later attempt, it is possible that the duplicated images will be unrestorable.

Article:TECH199640  |  Created: 2012-11-12  |  Updated: 2014-11-04  |  Article URL http://www.symantec.com/docs/TECH199640
Article Type
Technical Solution

Product(s)

Subject

Issue



A potential for data loss has been found when PDDO (PureDisk Deduplication Option) data removal runs against images where duplication failed initially, but succeeded on a later attempt.  Data loss can occur on the destination PDDO storage pool due to metadata being incorrectly imported into the PureDisk metabase.  The original (source) image is still restorable until it expires.

 


Environment



This issue can be seen when duplications fail and successfully retry to a PureDisk Deduplication Option (PDDO) storage pool (including NetBackup PureDisk Appliance 5000/5020 storage pools).  These duplications can be optimized duplications or duplications as a part of Auto Image Replication.

This issue is mostly likely to occur in environments where active duplication jobs are frequently manually terminated.

This issue affects MSDP (media server deduplication pool) servers running all versions of NetBackup through 7.5.0.3 (including all versions of NetBackup 5200/5220 Appliances through 2.5) when duplicating to PDDO storage on all versions of PureDisk through 6.6.3.  (This includes all versions of NetBackup PureDisk 5000/5020 Appliances through 1.4.2.) 

This issue also affects duplications from PDDO to PDDO on these same PureDisk and Appliance versions.


Cause



The root cause of this issue stems from duplication retries using the same POID (path object ID).


Solution



The formal resolution for this issue (Etracks 27348562943003) is included in the following releases:

  • NetBackup 7.5 Maintenance Release 4 (7.5.0.4)
  • NetBackup 5200/5220 Appliance Release Update 2.5.1
  • PureDisk 6.6 Release Update 4 (6.6.4)
  • NetBackup 5000/5020 Appliance Release Update 1.4.3.1

These releases are now available via the Related Articles linked below.

Please note that ALL affected products in the environment must be updated for this issue to be resolved.

Best Practices:
Symantec strongly recommends the following best practices:
1. Always perform a full DR backup prior to making any changes to your environment.
2. Always make sure that your environment is running the latest version and patch level.
3. Perform periodic "test" restores.
4. Subscribe to technical articles.

How to Subscribe to Email Notification:
Directly to this Article:
Subscribe to this article by clicking on the Subscribe via email link on this page to receive notification when this article is updated with Release Information.

Software Alerts:
If you have not received information about this TechNote from the Symantec Email Notification Service as a Software Alert, you may subscribe via email and/or RSS using the links provided at the following pages:
NetBackup Enterprise Server: http://www.symantec.com/business/support/index?page=content&key=15143&channel=ALERTS
NetBackup PureDisk: 
http://www.symantec.com/business/support/index?page=content&key=52672&channel=ALERTS
NetBackup Appliances: http://www.symantec.com/business/support/index?page=content&key=58991&channel=ALERTS


Supplemental Materials

SourceETrack
Value2943003
Description

Images missing from target domain that should have been replicated via SLP


SourceETrack
Value2734856
Description

PDDO Data Removal causes data loss on retried images




Article URL http://www.symantec.com/docs/TECH199640


Terms of use for this information are found in Legal Notices