[lustre-discuss] lester on mds with low memory
Mohr Jr, Richard Frank (Rick Mohr)
rmohr at utk.edu
Fri Mar 27 08:52:29 PDT 2015
> On Mar 27, 2015, at 4:38 AM, Alexander Oltu <Alexander.Oltu at uib.no> wrote:
>
> yes, right before starting Lester. I tried sending 1 and sending 3 to /proc/sys/vm/drop_caches, maximum I can get is 1.5 GB.
>
> I don’t know where the buffer memory is being used. Running “sync” didn’t change anything. I was thinking maybe this is something Lustre related.
I wonder if it is possible that you are hitting LU-5726. You might want to check the “Inactive(file)” line in /proc/meminfo to see if that accounts for most of the buffer usage. When I was hitting this bug, dropping caches would have no effect and I could not reclaim memory on my MDS server. After I applied the patch, I could consistently run “echo 3 > /proc/sys/vm/drop_caches” and reclaim almost all the memory on the MDS.
--
Rick Mohr
Senior HPC System Administrator
National Institute for Computational Sciences
http://www.nics.tennessee.edu
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