[Lustre-discuss] Lustre inode cache tunables

[Andreas Dilger]

On Jan 15, 2009  11:27 +0100, Jakob Goldbach wrote:
> I daily run 'find /lustre' on a filesystem with many files. This
> consumes a lot of memory and /proc/slabinfo reveals that
> lustre_inode_cache has ~9000000 objects.
> 
> I've seen the system swapping sometimes, causing slow responses and
> evictions. Any tunables for reclaming pages from the lustre_inode_cache
> slab? 

This is a problem with the Linux VFS more than Lustre itself.  A find
even on a local filesystem would generate this many inodes.

Depending on what you are doing with "find" you could instead use the
"lfs find" command.  This avoids instantiating inodes or requesting
any data from the OSTs unless it is absolutely required.  In many cases
"lfs find" can do its work with only information from the MDS, and it
does not need to instantiate the inode.

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.