[Gluster-devel] missing files

Xavier Hernandez xhernandez at datalab.es
Wed Feb 11 11:53:27 UTC 2015


Some time ago I had a similar performance problem (with 3.4 if I 
remember correctly): a just created volume started to work fine, but 
after some time using it performance was worse. Removing all files from 
the volume didn't improve the performance again.

The only way I had to recover a performance similar to the initial one 
without recreating the volume was to remove all volume contents and also 
delete all 256 .glusterfs/xx/ directories from all bricks.

The backend filesystem was XFS.

Could you try if this is the same case ?

Xavi

On 02/11/2015 12:22 PM, David F. Robinson wrote:
> Don't think it is the underlying file system. /data/brickxx is the underlying xfs. Performance to this is fine. When I created a volume it just puts the data in /data/brick/test2. The underlying filesystem shouldn't know/care that it is in a new directory.
>
> Also, if I create a /data/brick/test2 volume and put data on it, it gets slow in gluster. But, writing to /data/brick is still fine. And, after test2 gets slow, I can create a /data/test3 volume that is empty and its speed is fine.
>
> My knowledge is admittedly very limited here, but I don't see how it could be the underlying filesystem if the slowdown only occurs on the gluster mount and not on the underlying xfs filesystem.
>
> David  (Sent from mobile)
>
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>> On Feb 11, 2015, at 12:18 AM, Justin Clift <justin at gluster.org> wrote:
>>
>>> On 11 Feb 2015, at 03:06, Shyam <srangana at redhat.com> wrote:
>>> <snip>
>>> 2) We ran an strace of tar and also collected io-stats outputs from these volumes, both show that create and mkdir is slower on slow as compared to the fast volume. This seems to be the overall reason for slowness
>>
>> Any idea's on "why" the create and mkdir is slower?
>>
>> Wondering if it's a case of underlying filesystem parameters (for the bricks)
>> + maybe physical storage structure having become badly optimised over time.
>> eg if its on spinning rust, not ssd, and sector placement is now bad
>>
>> Any idea if there are tools that can analyse this kind of thing?  eg meta
>> data placement / fragmentation / on a drive for XFS/ext4
>>
>> + Justin
>>
>> --
>> GlusterFS - http://www.gluster.org
>>
>> An open source, distributed file system scaling to several
>> petabytes, and handling thousands of clients.
>>
>> My personal twitter: twitter.com/realjustinclift
>>
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