[Gluster-devel] Small File Performance - Strange results

Shyam srangana at redhat.com
Wed Aug 5 11:00:32 UTC 2015

On 08/04/2015 08:57 PM, Joe Julian wrote:
> On 08/04/2015 05:53 PM, Shyam wrote:
>> On 08/04/2015 12:55 PM, Hafeez Bana wrote:
>>> All,
>>> We've been evaluating glusterfs 3.2.7 on ubuntu 14.04 LTS. All tests
>>> were run with event-thread matching cpu-cores and lookup-unhashed
>>> turned off
>> I think you are referring to lookup-optimize rather than
>> lookup-unhashed, please use lookup-optimize which is meant for the
>> small file performance improvement.
> No, he means unhashed. lookup-optimize isn't in 3.2. One of his biggest
> problems will be the lack of readdirp support.

I will let Hafeez clarify, but event-threads is not present in 3.2.x 
line, it was introduced in the 3.7 line as a part of small file 
performance improvements. So going by the tone of the message the 
"3.2.7" mention seems to be a confusion , and is possibly 3.7.2 (which I 
will let the poster clarify :-) )

>>> We noted a couple of issues and some interesting results which might be
>>> of benefit to the developers
>>> Setup
>>> - bare metal machine with SSD running ZFS - 2 LXC container running
>>> glusterd and another running a samba instance which is serving a share
>>> backed by a fuse mounted volume.
>> There are too many things in the stack here to reliably measure
>> performance is what I would think.
>> I would first, run atop the FUSE mount and compare results with 3.6.x
>> to see if the options provided improve the performance or not.
>>> Observations
>>> 1 )  the fuse mounted volume has to be done in the host and LXC run on
>>> top of it. If you try to fuse mount within in LXC - posix acls group
>>> persmissions are not respected completed by gluster
>>> 2) small file performance - tests were run unzipping from a windows box
>>> a 45M and 150M  (expanded size - contains 8000 files) archive. 45M
>>> performance is reasonable. 150M tests takes 10 times as long(about 18
>>> minutes) as the same samba instance serving of a straight zfs filesystem
>>> 3) As a whim we logged into the container containing the samba instance
>>> and copied files from the ZFS folder to the folder under gluster.
>>> 14seconds for the same transfer of 8000 files!!
>>> We don't know if there is a mismatch in the config of samba that is
>>> causing issues with gluster. Any ideas? And also is the issue with posix
>>> acls groups being broken if you fuse_mount a gluster volume within LXC
>>> known?
>>> Finally, are there any gluster developers in the UK - we would love to
>>> talk to them.
>>> Thanks,
>>> Hafeez
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