[Lustre-discuss] MDS question

[Brian J. Murrell]

On Thu, 2008-08-14 at 08:05 -0400, Mag Gam wrote:
> What is the disadvantage of creating a MDS partition with smaller
> inodes per block? Now, its 4k per inode what happens if we go to the
> least blocks which is 1024k?

You risk running out of room in the inode for EAs, requiring that
another block be allocated to hold the additional EAs and it be linked
to the inode.  As you can imagine having to seek the disk to move from
the inode to the additional EA block has a performance penalty
associated with it.

> This would let us create more smaller
> files which will lead to more inodes used. But what is the downside?

Do you really have a use case where 4K inodes doesn't give you enough
files?

b.

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