[Lustre-devel] F/S stats visualisation
rf at q-leap.de
rf at q-leap.de
Tue May 17 06:43:14 PDT 2011
>>>>> "Johann" == Johann Lombardi <johann at whamcloud.com> writes:
Johann> On Tue, May 17, 2011 at 02:13:37PM +0200, rf at q-leap.de
Johann> wrote:
>> Which #blocks? The one of the MDT or the one of the whole FS?
Johann> The #blocks on the MDT.
Ah, OK, that's definitely the case here.
>> Does that imply I'm doing something wrong?
Johann> Lustre is just *very* conservative. If you format your MDT
Johann> with a #blocks/#inodes ratio of 1, you won't get this
Johann> problem.
I see. Unfortunately, we need that many inodes ...
>> What is an EA block anyway?
Johann> The file striping configuration is stored in an extended
Johann> attribute. Depending on the number of file stripes (can be
Johann> changed dynamically with lfs setstripe), this extended
Johann> attribute is stored either in the inode core or in an
Johann> additional data block. In the latter, you need to alloate
Johann> one data block for each file creation.
Got it.
>> We haven't activated any striping.
Johann> Then you use the default stripe count which is 1 and the
Johann> extended attribute fits in the inode. As i said in my first
Johann> email, we could probably do better and handle this at mkfs
Johann> time. Andreas' patch
Johann> (http://review.whamcloud.com/#change,480) introducing
Johann> --stripe-count-hint should help in this regard.
Great. Thanks a lot for this hint. Do you know whether this will eneter
the 1.8 branch as well?
Roland
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