[Lustre-discuss] Huge Sparse files in ROOT partition of MDT

[Nirmal Seenu]

Thanks for that explanation. It would be nice if this detail gets 
included in the Quota section of the Lustre Manual rather than users 
getting surprised by the huge tar files in the archives.

Is there a easy way to roll back the changes made by "lfs quotacheck" 
command where the huge sparse files are converted back into 0 byte files 
on the MDT?

Thanks
Nirmal

Andreas Dilger wrote:
> On Mar 06, 2009  07:26 -0600, Nirmal Seenu wrote:
>> While trying to figure out the reason for LVM2 snapshots failing on our 
>> MDT server I found that there are a lot of sparse files on the MDT 
>> volume. The file size as seen from a ls command output on the MDT is 
>> same as the real file size. The tar runs for a few hours at this point 
>> even if try to use the --spare option in the tar command.
> 
> All of the files on the MDT are sparse.  The data lives on the OSTs.
> 
>> The total MDT partition usage itself is about 500MB (as reported by df) 
>> and it used to take me less than 10 minutes to create a LVM2 snapshot 
>> and tar it up when I was running the servers using Lustre 1.6.5 with no 
>> quota enabled.
>>
>> I recently upgraded my Lustre servers to 1.6.7 and tried to enable quota 
>> on the MDT and OST by doing the following commands:
> 
> Also, the quota file is a huge sparse file, size proportional to the
> highest UID in use.
> 
> 
> Cheers, Andreas
> --
> Andreas Dilger
> Sr. Staff Engineer, Lustre Group
> Sun Microsystems of Canada, Inc.
>