[lustre-discuss] problem on the MDT after upgrading lustre version

[Riccardo Veraldi]

Hello,

Yesterday I upgraded one of my filesystems from Lustre 2.10.5 to Lustre 
2.12.0

everything apparently went well. I Also upgraded form zfs 0.7.9 to zfs 
0.7.12

I also ahve another cluster with a clean 2.12.0 install and it works 
well and performs well

Today after the yesterday's upgrade I noticed that the clients could not 
mount the filesystem anymore and the clients had this error

Mar  1 14:41:15 psexport07 kernel: LustreError: 
1355:0:(lmv_obd.c:1412:lmv_statfs()) can't stat MDS #0 
(ana15-MDT0000-mdc-ffff9cf3b03e0000), error -11
Mar  1 14:41:16 psexport07 kernel: LustreError: 
1355:0:(lov_obd.c:831:lov_cleanup()) ana15-clilov-ffff9cf3b03e0000: lov 
tgt 1 not cleaned! deathrow=0, lovrc=1


mount operation would just hang with no error on the MDS or on the OSS

After rebooting the MDS/MDT server everything is apparently fixed.

I wonder what could be the cause of this. I have checked the networking 
and LNet configuration and everything is properly configured.

lctl ping works and anyway nothing has been changed in the configuration 
from 2.10.5 to 2.12.0

Any hints are very appreciated.

thanks

Rick