[Gluster-devel] missing files
David F. Robinson
david.robinson at corvidtec.com
Wed Feb 11 12:31:25 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.
I guess my problem is a little better depending on how you look at it. If I date the data from the volume, the performance goes back to that of an empty volume. I don't have to delete the .glusterfs entries to regain my performance. I only have to delete the data from the mount point.
> 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 ?
>> 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)
>> David F. Robinson, Ph.D.
>> President - Corvid Technologies
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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:
>>>> 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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