Differential backup with "Use Change Journal" and "Allow multiple data streams" settings for non-ASCII path name may result in data loss

Differential backup with "Use Change Journal" and "Allow multiple data streams" settings for non-ASCII path name may result in data loss

  • Article ID:100044060
  • Last Published:
  • Product(s):NetBackup

Problem

Differential backup with Use Change Journal and Allow multiple data streams settings for non-ASCII path name may result in data loss. (Etrack 3953554)

Error Message

From the bpfis log:

16:32:51.537 [352.7528] <4> bpfis main: parameter client_type 13, fis_accl 0, fis_accl_cksv -1, SNAPSHOT_IS_HERE 1

16:32:51.537 [352.7528] <4> PauseChangeJournalDatabases:

Volume guid list is empty, will not pause and flush NetBackup Change Journal databases

16:32:51.537 [352.7528] <4> bpfis main: read_registry_dw_value for VSS_CONCURRENT_OPERATIONS: return status 2, return value 0

Cause

The following combination of configurations potentially causes data loss in MS-Windows type policy backup.

  1. Use Change Journal option is activated on Windows backup client.
  2. Backup policy configured with the following

         [Attributes]                 -> MS-Windows is chosen as a policy type
         [Attributes]                 -> Allow Multiple Data Streams is enabled
         [Schedules]                -> With Differential schedule
         [Backup Selections]   -> Path name contains non-ASCII character
     
  3. NetBackup Change Journal databases (VxCJ*.dat) contains valid USN journal ID prior to the affected backup.

Backups update Change Journal databases properly if its Backup Selections do not have non-ASCII character. The differential backup fails to detect changes on file system, because NetBackup Change Journal databases are not updated with the above condition.

When Allow Multiple Data Streams is enabled, bpfis handles backup target path name whose encoding is UTF-8.

The bpfis process calls an ANSI version Windows API to retrieve cross mount point attributes.

However, it doesnt occur, because ANSI version Windows API cannot recognize multi-byte character.

NetBackup Change Journal databases wont be updated so that bpbkar32.exe misses all changes on the file system.


Affected Versions

This issue affects NetBackup versions 7.5.0.7 through NetBackup 8.1.2.


Solution

A HotFix is available for NetBackup 8.1.1 which resolves the this issues.  This hotfix is to be installed on all windows NetBackup 8.1.1 servers and clients.  The HotFix can be downloaded from the attached related Article.

 

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