When using Inline Tape Copy to create multiple copies of VMware images, block-level incremental backups based on full backups may expire earlier than expected when Copy 1 of the full backup expires.

Article:TECH201453  |  Created: 2013-01-08  |  Updated: 2013-01-16  |  Article URL http://www.symantec.com/docs/TECH201453
Article Type
Technical Solution


Subject

Issue



Introduction:
When enabling multiple copies of block-level incremental backups (BLIBs) for VMware backups, all incremental images are associated with the full backup's "Copy 1" and expire when that copy expires.  This means that there is a potential for incremental images which should be associated with Copy 2 (or above) to be expired after Copy 1 of the associated full backup expires but before Copy 2 (or above) has expired.

 


Error



When attempting to restore from a block level incremental backup, it is discovered that the image no longer exists, even though the expected expiry date has not come to pass, while the associated copy of the full backup is still available as expected.  This may lead to results where the only available means for restoration of a VMware backup are at an earlier point in time than expected because the restoration must be taken using a full backup instead of the incremental.


Environment



What is Affected:

This issue affects NetBackup for VMware versions 7.5 through 7.5.0.4 on all supported platforms (including NetBackup 5200/5220 Appliances 2.5 and 2.5.1).

 

How to Determine if Affected:

This issue affects policies of type VMware when multiple copies have been configured with Copy 2 (and above) having a longer retention period than Copy 1.  This is also known as Inline Tape Copy (ITC).  In this figure, the Multiple copies check box in the policy schedule has been selected:

This issue does not affect other policy types.

Additionally, Enable block-level incremental backup is enabled in the policy:


Solution



The formal resolution to this issue (Etrack 2978518) is included in the following releases:

  • NetBackup for VMware 7.5 Release Update 5 (7.5.0.5), currently scheduled for release in the first quarter of 2013
  • NetBackup 5200/5220 Appliance 2.5.2, to be simultaneously released with NetBackup 7.5.0.5

When NetBackup 7.5.0.5 is released, please access the following link for download and README information:
 http://www.symantec.com/business/support/index?page=landing&key=15143

Workaround:

Reconfigure affected policies to either not perform block level incremental backups, or reconfigure the policy to either not enable Multiple copies or adjust the retention levels of multiple copies so that Copy 1 expires last.

 

If these workarounds are unfeasible, please contact Symantec technical support, referencing this document ID and Etrack 2978501 to determine if an Emergency Engineering Binary (EEB) replacement for bpdbm may be available.

 

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.

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Supplemental Materials

SourceETrack
Value2978518
Description

With Inline Tape Copies, all VMware incrementals expire when full copy 1 expires.



Article URL http://www.symantec.com/docs/TECH201453


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