[Lustre-discuss] Problems with multiple lustre filesystems

[gregoire.pichon at bull.net]

> De : THIELL Stephane <stephane.thiell at cea.fr>
> 
> J Alejandro Medina a écrit :
> > When copying data from one filesystem to the other we experience 
> > excessive broadcast messages. The network crawls down to its knees 
> > until both filesystems stop responding. 
> >
> > If we test both filesystems separately we do not see this behavior.
> An idea could be to reduce your lustre client max_cached_mb value 
> (per-filesystem value). By default, it is set to 2/3 of available system 

> memory so it's not optimal when mounting multiple lustre filesystems on 
> the same node, especially when copying data from one to the other.
> 
> see /proc/fs/lustre/llite/*/max_cached_mb
> 

Looking at the code (lustre 2.0) it appears the max_cached_mb tunable has 
no effect.
I have found LU-141 "port lustre client page cache shrinker back to clio" 
that tracks the problem.

--
Grégoire PICHON
Bull

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