[Lustre-discuss] Understanding lfs output

[Mag Gam]

Brian:

Yes, I have looked thru the lists but I could not really get this
question answered. tune2fs is a ext2/3 setting, and I though each file
I create on a Lustre filesystem an inode gets created on the MDS and
the OST as an object.

But, I don't understand how there is that much of a space discrepancy.
Also, how does striping account for in inodes? Lets say I stipe a file
on 4 OSTs, I suppose 5 (1 for MDS, 4 for OSTs) inodes are occupied,
correct?

Sorry for a newbie question.

TIA



On Tue, Aug 19, 2008 at 4:30 PM, Brian J. Murrell <Brian.Murrell at sun.com> wrote:
> On Sun, 2008-08-17 at 15:50 -0700, Mag Gam wrote:
>> My departments Lustre's lfs df -i looks like this
>>
>> UUID                    Inodes     IUsed     IFree IUse% Mounted on
>> xfs001-MDT0000_UUID   82565322  19073586  63491736   23%
>> /xfs/engine1/xfs001[MDT:0]
>> xfs001-OST0000_UUID   41943040   5076445  36866595   12%
>> /xfs/engine1/xfs001[OST:0]
>> xfs001-OST0001_UUID   41943040   3735715  38207325    8%
>> /xfs/engine1/xfs001[OST:1]
>> xfs001-OST0002_UUID   41943040   4784447  37158593   11%
>> /xfs/engine1/xfs001[OST:2]
>> xfs001-OST0003_UUID   41943040   4556627  37386413   10%
>> /xfs/engine1/xfs001[OST:3]
>>
>> filesystem summary:   82565322  19073586  63491736   23% /xfs/engine1/xfs001
>>
>>
>> Is it safe to say, "
>> My MDT has "19073586" 19 million inodes free? or should I consider.
>>
>> However, when I check my inode count on my mds using tune2fs it reports this.
>> Inode count:              524288000
>> Free inodes:              505214414
>>
>> Am I missing something?
>
> Yes.  lfs df does not simply report the free inodes on the MDT.  It's
> more complicated than that.  This has been discussed either here or in a
> bugzilla bug (don't recall which).  I don't recall the bug or when the
> lustre-discussion was, offhand, but a search should not be terribly
> difficult to find the answer.
>
> b.
>
>
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