[Lustre-discuss] MDS memory usage

[Bernd Schubert]

On Tuesday, August 24, 2010, Frederik Ferner wrote:
> Hi List,
> 
> on our MDS we noticed that all memory seems to be used. (And it's not
> just normal buffers/cache as far as I can tell.)
> 
> When we put load on the machine, for example by starting rsync
> on a few clients, generating file lists to copy data from Lustre to
> local disks or just running a MDT backup locally using dd/gzip to copy a
> LVM snapshot to a remote server, kswapd starts using a lot of CPU
> time, sometimes up to 100% of one CPU core.
> 
> This is on a Lustre 1.6.7.2.ddn3.5 based file system with about 200TB,
> the MDT is 800GB with 200M inodes, ACLs enabled.

Did you recompile it, or did you use the binaries from my home page (or those 
you got from CV)?

Possibly it is a LRU auto-resize problem, but which has been disabled in DDN 
builds. As our 1.6 releases didn't include a patch for that, you would need to 
specify the correct command options if you recompiled it.

Another reason might be bug 22771, although that should only come up on MDS 
with more memory you have.


Cheers,
Bernd

-- 
Bernd Schubert
DataDirect Networks