[Gluster-users] Very slow roaming profiles on top of glusterfs

Mon Sep 14 14:40:04 UTC 2015

Hi Diego,

In the end I opted for MooseFS. I am still investigating GlusterFS for 
virtualisation though.

Cheers

Alex

On 14/09/15 14:26, Diego Remolina wrote:
> Hi Alex,
>
> Thanks for the reply, I was aware of the performance issues with small
> files, but never expected an order of magnitude slower. I understand
> some improvements were made to 3.7.x to help with low small file
> performance, however I did not see any big changes after upgrading
> from 3.6.x to 3.7.x.
>
> http://www.gluster.org/community/documentation/index.php/Features/Feature_Smallfile_Perf
>
> And the ssd metadata support feature seems to have not had any changes
> since September 2014:
>
> https://forge.gluster.org/gluster-meta-data-on-ssd
>
> Am I just totally out of luck with gluster for now?
>
> Diego
>
> On Mon, Sep 14, 2015 at 8:37 AM, Alex Crow <acrow at integrafin.co.uk> wrote:
>> Hi Diego,
>>
>> I think it's the overhead of fstat() calls. Gluster keeps its metadata on
>> the bricks themselves, and this has to be looked up for every file access.
>> For big files this is not an issue as it only happens once, but when
>> accessing lots of small files this overhead rapidly builds up, the smaller
>> the file the worse the issue. Profiles do have hundreds of very small files!
>>
>> I was looking to use GlusterFS for generic file sharing as well, but I
>> noticed the same issue while testing backups from a GlusterFS volume. On one
>> vol (scanned 4-bit greyscale images and small PDFs) backups were taking over
>> 16 hours whereas with a traditional FS they were completing in just over 1
>> hour.
>>
>> It may be worth trying out one of the distributed filesystems that use a
>> separate in-memory metadata server. I've tried LizardFS and MooseFS and they
>> are both much faster than GlusterFS for small files, although large-file
>> sequential performance is not as good (but still plenty for a Samba server).
>>
>> Alex
>>
>>
>> On 14/09/15 13:21, Diego Remolina wrote:
>>> Bump...
>>>
>>> Anybody has any clues as to how I can try and identify the cause of
>>> the slowness?
>>>
>>> Diego
>>>
>>> On Wed, Sep 9, 2015 at 7:42 PM, Diego Remolina <dijuremo at gmail.com> wrote:
>>>> Hi,
>>>>
>>>> I am running two glusterfs servers as replicas. I have a 3rd server
>>>> which provides quorum. Since gluster was introduced, we have had an
>>>> issue where windows roaming profiles are extremely slow. The initial
>>>> setup was done on 3.6.x and since 3.7.x has small file performance
>>>> improvements, I upgraded to 3.7.3, but that has not helped.
>>>>
>>>> It seems that for some reason gluster is very slow when dealing with
>>>> lots of small files. I am not sure how to really troubleshoot this via
>>>> samba, but I have come up with other tests that produce rather
>>>> disconcerting results as shown below.
>>>>
>>>> If I run directly on the brick:
>>>> [root at ysmha01 /]# time ( find
>>>> /bricks/hdds/brick/home/jgibbs/.winprofile.V2 -type f > /dev/null )
>>>> real 0m3.683s
>>>> user 0m0.042s
>>>> sys 0m0.154s
>>>>
>>>> Now running on the gluster volume mounted via fuse:
>>>> [root at ysmha01 /]# mount | grep export
>>>> 10.0.1.6:/export on /export type fuse.glusterfs
>>>> (rw,relatime,user_id=0,group_id=0,allow_other,max_read=131072)
>>>>
>>>> [root at ysmha01 /]# time ( find /export/home/jgibbs/.winprofile.V2 -type
>>>> f > /dev/null )
>>>> real 0m57.812s
>>>> user 0m0.118s
>>>> sys 0m0.374s
>>>>
>>>> In general, the time to run the command on this particular user can be
>>>> up to 2 minutes. If I run the command on the brick first, then it
>>>> seems the time to run on the mounted gluster volume is lower like in
>>>> the example above. I assume some caching in preserved.
>>>>
>>>> This particular user has 13,216 files in his roaming profile, which
>>>> adds up to about 452MB of data.
>>>>
>>>> The server performance over samba for copying big files (both read and
>>>> write) is great, I can almost max out the gigabit connections on the
>>>> desktops.
>>>>
>>>> Reading from samba share on the server and writing to local drive:
>>>> 111MB/s (Copying a 650MB iso file)
>>>> Reading from local drive and writing to server samba share: 94MB/s
>>>> (Copying a 3.2GB ISO file)
>>>>
>>>> The servers are connected to the network with 10Gbit adapters and also
>>>> use separate adapters; one 10 Gbit adapter is used for services, and
>>>> other for the backend storage communication.
>>>>
>>>> The servers have hardware raid controllers and the samba shares are on
>>>> top of an Areca ARC-1882 controller, with a volume made out of 12 2TB
>>>> drives in raid 6.
>>>>
>>>> If you can provide any steps to better troubleshoot this problem and
>>>> fix the issue, I will really appreciate it.
>>>>
>>>> Diego
>>>>
>>>> Further details about the machines below:
>>>>
>>>> [root at ysmha01 /]# cat /etc/redhat-release
>>>> CentOS Linux release 7.1.1503 (Core)
>>>>
>>>> [root at ysmha01 /]# gluster volume info export
>>>> Volume Name: export
>>>> Type: Replicate
>>>> Volume ID: b4353b3f-6ef6-4813-819a-8e85e5a95cff
>>>> Status: Started
>>>> Number of Bricks: 1 x 2 = 2
>>>> Transport-type: tcp
>>>> Bricks:
>>>> Brick1: 10.0.1.7:/bricks/hdds/brick
>>>> Brick2: 10.0.1.6:/bricks/hdds/brick
>>>> Options Reconfigured:
>>>> performance.io-cache: on
>>>> performance.io-thread-count: 64
>>>> nfs.disable: on
>>>> cluster.server-quorum-type: server
>>>> performance.cache-size: 1024MB
>>>> server.allow-insecure: on
>>>> cluster.server-quorum-ratio: 51%
>>>>
>>>> Each server has dual Intel(R) Xeon(R) CPU E5-2620 0 @ 2.00GHz with
>>>> 32GB of memory.
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