[Lustre-discuss] Slow Directory Listing

Adrian Ulrich adrian at blinkenlights.ch
Tue Sep 6 12:58:59 PDT 2011


> While normal file access works fine, the directory listing is extremely
> slow.
> Depending on the number of files in a directory, the listing takes around 5
> - 15 secs.
> 
> I tried 'ls --color=none' and it worked fine; listed the contents
> immediately.

That's because 'ls --color=always|auto' does an lstat() of each file (--color=none doesn't) which causes Lustre to send:

 - 1 RPC to the MDS per file
 - 1 RPC (per file) to EACH OSS where the file is stored to get the filesize

Some time ago i've created a patch to speed up 'ls' while keeping (most) of the colors
(https://github.com/adrian-bl/patchwork/blob/master/coreutils/ls/ls-lustre.diff)

But patching samba will not be possible in your case as it really needs the information returned by stat().


> Double clicking on directory takes a long long time to display.

Attach `strace' to samba: It will probably be busy doing lstat() which is a 'slow' operation on Lustre in any case.



> The cluster consist of -
> - two DRBD Mirrored MDS Servers (Dell R610s) with 10K RPM disks
> - four OSS Nodes (2 Node Cluster (Dell R710s) with a common storage (Dell
> MD3200))

How many OSTs do you have per OSS?
What's your stripe setting? Setting the stripe to 1 could give you a huge speedup (without affecting normal I/O as i assume that the 9MB files are read/written sequentially)


Regards,
 Adrian


-- 
 RFC 1925:
   (11) Every old idea will be proposed again with a different name and
        a different presentation, regardless of whether it works.




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