[Lustre-discuss] MDS question

[Mag Gam]

Brian:

What is an EA?

Yes. We create 20k files per day. Multiple that by 360days per year
(for our research), thats about 72000000 files per year

We have 11 years of data. 792000000 files

OUr file size range from 5M to 70M (average)


I know its crazy but a professor or studeny will need any of these
year datasets at random. So far lustre has been awesome, just the
inode issue.


TIA






On Wed, Aug 20, 2008 at 5:12 PM, Brian J. Murrell <Brian.Murrell at sun.com> wrote:
> 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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