Troubleshooting
Problem
An HSM client tries to migrate a file and fails with the following error :
[]ANS9531E migrate1: cannot create a DM session: old session = 0
session info = dsmmigrate. Reason : Not enough space[]
Symptom
Other HSM commands, like the dsmmigfs query command, also fail with the same error.
Diagnosing The Problem
Run the "mmfsadm dump dmapi" GPFS command to verify the DMAPI sessions. For example :
#mmfsadm dump dmapi
...
Sessions created at this node (<c0n0>):
DM sessions: 28
...
Sessions known at session manager (this node):
DM sessions: 4000
...
node address id (hex) regformount status cleanupTicks info
<c0n0> 000000005728f9fa n valid inactive dsmc
Created on Wed Oct 19 19:19:08 2016
...
<c0n1> 00000000588266b4 n valid inactive automig2
Created on Fri Jan 20 14:36:20 2017
<c0n1> 00000000588266be n valid inactive automig2
Created on Fri Jan 20 14:36:30 2017
<c0n1> 00000000588266c8 n valid inactive automig2
Created on Fri Jan 20 14:36:40 2017
<c0n1> 00000000588266d2 n valid inactive automig2
Created on Fri Jan 20 14:36:50 2017
...
Examine the latest GPFS log for errors. For example :
# tail -5 /var/adm/ras/mmfs.log.latest
<timestamp>: Failed to create dm session, only <4000> sessions are allowed.
...
GPFS apar IY87796 implemented a limit of 4000 DMAPI sessions. The above data shows the limit of 4000 sessions was reached, which caused the ANS9531E error to be logged with "Reason : Not enough space".
Resolving The Problem
In this example, the majority of DMAPI sessions were used by the automig2 process on the second node of the GPFS cluster. Use the "ps -ef | grep dsm" command to HSM daemons. Use the "kill -15" command to stop the dsmautomig and dsmwatchd process, which should release the DMAPI sessions. If there are no HSM daemons runnning, which indicates the DMAPI sessions or orphaned, contact IBM support for further investigation.
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Document Information
Modified date:
17 June 2018
UID
swg21998588