[Gluster-devel] ls again

[Anand Avati]

Reinis,
 ls commands on modern GNU/Linux systems run xattr calls on each entry for
ACL purposes. This can turn out to be pretty expensive in terms of
performance. If you just run /bin/ls, or ls after 'unalias ls', you should
observe that the performance improves quite a bit, either because both
stat() and xattr calls were skipped, or because just stat() calls were
skipped.

avati

2008/4/7, Reinis Rozitis <roze at roze.lv>:
>
> Hello,
> there have been some threads in the past about 'ls' being slow on large
> file
> directories but my question is more regarding documentation:
>
> According to http://www.gluster.org/docs/index.php/GlusterFS_FAQ - "Just
> doing "ls" doesn't trigger stat call. It should be fast as this is called
> only on the namespace child."
>
> But actually on our system/setup (where namespace resides on seperate
> partition (c0d0) and the storage bricks are different pairs of disks
> (c1d0-c2d6) mounted together with unify) we see that after doing 'ls' a
> sequence starts which reads every storage brick (and not only namespace).
>
>
> In iostat it looks something like this (I hope the spacing won't break):
>
> avg-cpu:  %user   %nice %system %iowait  %steal   %idle
> 0.00    0.00    0.50    0.00    0.00   99.50
>
> Device:            tps   Blk_read/s   Blk_wrtn/s   Blk_read   Blk_wrtn
> cciss/c0d0        0.00         0.00         0.00          0          0
> cciss/c1d0        0.00         0.00         0.00          0          0
> cciss/c1d1        0.00         0.00         0.00          0          0
> cciss/c1d2        0.00         0.00         0.00          0          0
> cciss/c1d3      189.00      3008.00         0.00       3008          0
> cciss/c1d4        0.00         0.00         0.00          0          0
> cciss/c1d5        0.00         0.00         0.00          0          0
> cciss/c1d6        0.00         0.00         0.00          0          0
> cciss/c1d7        0.00         0.00         0.00          0          0
> cciss/c1d8        0.00         0.00         0.00          0          0
> cciss/c1d9        0.00         0.00         0.00          0          0
> cciss/c2d0        0.00         0.00         0.00          0          0
> cciss/c2d1        0.00         0.00         0.00          0          0
> cciss/c2d2        0.00         0.00         0.00          0          0
> cciss/c2d3        0.00         0.00         0.00          0          0
> cciss/c2d4        0.00         0.00         0.00          0          0
> cciss/c2d5        0.00         0.00         0.00          0          0
> cciss/c2d6        0.00         0.00         0.00          0          0
>
>
> There is only one partition being read at time when it finishes it
> switches
> to the next. Sometimes the loop goes even 2 or 3 times before the
> directory/file listing is returned. So it takes pretty long after the
> mounted partition becomes responsive.
>
> I wonder is it supposed to be so or the 'ls' from OpenSuse "breaks" the
> whole thing (because it adds some commandline params on its own - full
> command looks like 'ls -N --color=tty -T 0 -1')
>
> wbr
> Reinis Rozitis
>
>
>
> _______________________________________________
> Gluster-devel mailing list
> Gluster-devel at nongnu.org
> http://lists.nongnu.org/mailman/listinfo/gluster-devel
>



-- 
If I traveled to the end of the rainbow
As Dame Fortune did intend,
Murphy would be there to tell me
The pot's at the other end.