Undercount of DAOS references in .NSF files created while resync is running can lead to missing .NLO files

Technote (troubleshooting)


Problem

If the reference counts are lower than they should be, the associated .NLO files will be made available for pruning before they should be.

Cause

(SPR #BBSZ98UKRV)
References can be undercounted in an .NSF file if DAOS resync is running while the .NSF file is created. This problem can occur while the DAOS catalog state is labeled as 'REBUILDING,' which occurs for a short time early in the resync process. This undercounting of references can lead to .NLO files' being pruned prematurely, which can cause missing NLO files. The symptoms are missing .NLO files, or the DAOS catalog state changing to Needs Resync with the following diagnostic message:

DAOSDeleteObject - 2

NOTE There may also be other reasons for the same situations, and these events may not conclusively prove that a server is experiencing this specific problem.

This problem occurs when a new .NSF is created, and new DAOS references are added to that file while the DAOS catalog is in the 'REBUILDING' state. The problem can be aggravated by running copy-style compact while resync is running. Copy-style compact creates a new .NSF and then copies all of the data from the original .NSF into the new one. The high volume of traffic to the new .NSF during this time can cause a significant number of references to be created in this short period.

There is a fix available, and it is applicable to versions 8.5.2 through 9.0 of Domino. After the fix is applied, a "daosmgr resync" (or "daosmgr resync force" if the DAOS catalog is in SYNCHRONIZED state) operation should be performed to ensure the counts are accurate. After that is done, no further undercounting or premature pruning will occur as a result of this issue. It's important to follow best practice and have a good backup/restore process in place for the .NLO data. The fix will not recover any .NLO files that have been deleted prematurely, and those should be restored from backup as needed.

Any missing .NLO files will be indicated by console messages during resync, for example:

The database <NSF name> has a reference to <NLO name>, which does not exist.  An entry has been added to the DAOS catalog indicating the NLO is missing


Diagnosing the problem

The symptoms are missing .NLO files, or the DAOS catalog state changing to Needs Resync with the following diagnostic message:


DAOSDeleteObject - 2

NOTE There may also be other reasons for the same situations, and these events may not conclusively prove that a server is experiencing this specific problem.


Resolving the problem

As a workaround without the fix, run a "daosmgr resync" (or "daosmgr resync force" if the DAOS catalog is in SYNCHRONIZED state) to ensure the counts are accurate. Do not run copy-style compact or create new DAOS-enabled .NSF files after the initiation of DAOS resync, until the DAOS catalog state changes to 'REBUILDING.' After the state reaches 'RESYNCING,' this problem will no longer occur, and normal operations can resume.

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Document information


More support for:

IBM Domino
DAOS

Software version:

8.5.2, 8.5.2.1, 8.5.2.2, 8.5.2.3, 8.5.2.4, 8.5.3, 8.5.3.1, 8.5.3.2, 8.5.3.3, 8.5.3.4, 9.0

Operating system(s):

AIX, AIX 64bit, IBM i, Linux, Linux iSeries, Linux xSeries, Linux zSeries, Solaris, Windows, Windows 64bit, i5/OS, z/OS

Reference #:

1646418

Modified date:

2014-06-18

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