[Gluster-users] Slow write times to gluster disk
Pranith Kumar Karampuri
pkarampu at redhat.com
Wed May 31 01:54:34 UTC 2017
Thanks this is good information.
+Soumya
Soumya,
We are trying to find why kNFS is performing way better than plain
distribute glusterfs+fuse. What information do you think will benefit us to
compare the operations with kNFS vs gluster+fuse? We already have profile
output from fuse.
On Wed, May 31, 2017 at 7:10 AM, Pat Haley <phaley at mit.edu> wrote:
>
> Hi Pranith,
>
> The "dd" command was:
>
> dd if=/dev/zero count=4096 bs=1048576 of=zeros.txt conv=sync
>
> There were 2 instances where dd reported 22 seconds. The output from the
> dd tests are in
>
> http://mseas.mit.edu/download/phaley/GlusterUsers/TestVol/
> dd_testvol_gluster.txt
>
> Pat
>
>
> On 05/30/2017 09:27 PM, Pranith Kumar Karampuri wrote:
>
> Pat,
> What is the command you used? As per the following output, it seems
> like at least one write operation took 16 seconds. Which is really bad.
>
> 96.39 1165.10 us 89.00 us *16487014.00 us* 393212 WRITE
>
>
>
> On Tue, May 30, 2017 at 10:36 PM, Pat Haley <phaley at mit.edu> wrote:
>
>>
>> Hi Pranith,
>>
>> I ran the same 'dd' test both in the gluster test volume and in the
>> .glusterfs directory of each brick. The median results (12 dd trials in
>> each test) are similar to before
>>
>> - gluster test volume: 586.5 MB/s
>> - bricks (in .glusterfs): 1.4 GB/s
>>
>> The profile for the gluster test-volume is in
>>
>> http://mseas.mit.edu/download/phaley/GlusterUsers/TestVol/pr
>> ofile_testvol_gluster.txt
>>
>> Thanks
>>
>> Pat
>>
>>
>>
>>
>> On 05/30/2017 12:10 PM, Pranith Kumar Karampuri wrote:
>>
>> Let's start with the same 'dd' test we were testing with to see, what the
>> numbers are. Please provide profile numbers for the same. From there on we
>> will start tuning the volume to see what we can do.
>>
>> On Tue, May 30, 2017 at 9:16 PM, Pat Haley <phaley at mit.edu> wrote:
>>
>>>
>>> Hi Pranith,
>>>
>>> Thanks for the tip. We now have the gluster volume mounted under
>>> /home. What tests do you recommend we run?
>>>
>>> Thanks
>>>
>>> Pat
>>>
>>>
>>>
>>> On 05/17/2017 05:01 AM, Pranith Kumar Karampuri wrote:
>>>
>>>
>>>
>>> On Tue, May 16, 2017 at 9:20 PM, Pat Haley <phaley at mit.edu> wrote:
>>>
>>>>
>>>> Hi Pranith,
>>>>
>>>> Sorry for the delay. I never saw received your reply (but I did
>>>> receive Ben Turner's follow-up to your reply). So we tried to create a
>>>> gluster volume under /home using different variations of
>>>>
>>>> gluster volume create test-volume mseas-data2:/home/gbrick_test_1
>>>> mseas-data2:/home/gbrick_test_2 transport tcp
>>>>
>>>> However we keep getting errors of the form
>>>>
>>>> Wrong brick type: transport, use <HOSTNAME>:<export-dir-abs-path>
>>>>
>>>> Any thoughts on what we're doing wrong?
>>>>
>>>
>>> You should give transport tcp at the beginning I think. Anyways,
>>> transport tcp is the default, so no need to specify so remove those two
>>> words from the CLI.
>>>
>>>>
>>>> Also do you have a list of the test we should be running once we get
>>>> this volume created? Given the time-zone difference it might help if we
>>>> can run a small battery of tests and post the results rather than
>>>> test-post-new test-post... .
>>>>
>>>
>>> This is the first time I am doing performance analysis on users as far
>>> as I remember. In our team there are separate engineers who do these tests.
>>> Ben who replied earlier is one such engineer.
>>>
>>> Ben,
>>> Have any suggestions?
>>>
>>>
>>>>
>>>> Thanks
>>>>
>>>> Pat
>>>>
>>>>
>>>>
>>>> On 05/11/2017 12:06 PM, Pranith Kumar Karampuri wrote:
>>>>
>>>>
>>>>
>>>> On Thu, May 11, 2017 at 9:32 PM, Pat Haley <phaley at mit.edu> wrote:
>>>>
>>>>>
>>>>> Hi Pranith,
>>>>>
>>>>> The /home partition is mounted as ext4
>>>>> /home ext4 defaults,usrquota,grpquota 1 2
>>>>>
>>>>> The brick partitions are mounted ax xfs
>>>>> /mnt/brick1 xfs defaults 0 0
>>>>> /mnt/brick2 xfs defaults 0 0
>>>>>
>>>>> Will this cause a problem with creating a volume under /home?
>>>>>
>>>>
>>>> I don't think the bottleneck is disk. You can do the same tests you did
>>>> on your new volume to confirm?
>>>>
>>>>
>>>>>
>>>>> Pat
>>>>>
>>>>>
>>>>>
>>>>> On 05/11/2017 11:32 AM, Pranith Kumar Karampuri wrote:
>>>>>
>>>>>
>>>>>
>>>>> On Thu, May 11, 2017 at 8:57 PM, Pat Haley <phaley at mit.edu> wrote:
>>>>>
>>>>>>
>>>>>> Hi Pranith,
>>>>>>
>>>>>> Unfortunately, we don't have similar hardware for a small scale
>>>>>> test. All we have is our production hardware.
>>>>>>
>>>>>
>>>>> You said something about /home partition which has lesser disks, we
>>>>> can create plain distribute volume inside one of those directories. After
>>>>> we are done, we can remove the setup. What do you say?
>>>>>
>>>>>
>>>>>>
>>>>>> Pat
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On 05/11/2017 07:05 AM, Pranith Kumar Karampuri wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Thu, May 11, 2017 at 2:48 AM, Pat Haley <phaley at mit.edu> wrote:
>>>>>>
>>>>>>>
>>>>>>> Hi Pranith,
>>>>>>>
>>>>>>> Since we are mounting the partitions as the bricks, I tried the dd
>>>>>>> test writing to <brick-path>/.glusterfs/<file-to-be-removed-after-test>.
>>>>>>> The results without oflag=sync were 1.6 Gb/s (faster than gluster but not
>>>>>>> as fast as I was expecting given the 1.2 Gb/s to the no-gluster area w/
>>>>>>> fewer disks).
>>>>>>>
>>>>>>
>>>>>> Okay, then 1.6Gb/s is what we need to target for, considering your
>>>>>> volume is just distribute. Is there any way you can do tests on similar
>>>>>> hardware but at a small scale? Just so we can run the workload to learn
>>>>>> more about the bottlenecks in the system? We can probably try to get the
>>>>>> speed to 1.2Gb/s on your /home partition you were telling me yesterday. Let
>>>>>> me know if that is something you are okay to do.
>>>>>>
>>>>>>
>>>>>>>
>>>>>>> Pat
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> On 05/10/2017 01:27 PM, Pranith Kumar Karampuri wrote:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> On Wed, May 10, 2017 at 10:15 PM, Pat Haley <phaley at mit.edu> wrote:
>>>>>>>
>>>>>>>>
>>>>>>>> Hi Pranith,
>>>>>>>>
>>>>>>>> Not entirely sure (this isn't my area of expertise). I'll run your
>>>>>>>> answer by some other people who are more familiar with this.
>>>>>>>>
>>>>>>>> I am also uncertain about how to interpret the results when we also
>>>>>>>> add the dd tests writing to the /home area (no gluster, still on the same
>>>>>>>> machine)
>>>>>>>>
>>>>>>>> - dd test without oflag=sync (rough average of multiple tests)
>>>>>>>> - gluster w/ fuse mount : 570 Mb/s
>>>>>>>> - gluster w/ nfs mount: 390 Mb/s
>>>>>>>> - nfs (no gluster): 1.2 Gb/s
>>>>>>>> - dd test with oflag=sync (rough average of multiple tests)
>>>>>>>> - gluster w/ fuse mount: 5 Mb/s
>>>>>>>> - gluster w/ nfs mount: 200 Mb/s
>>>>>>>> - nfs (no gluster): 20 Mb/s
>>>>>>>>
>>>>>>>> Given that the non-gluster area is a RAID-6 of 4 disks while each
>>>>>>>> brick of the gluster area is a RAID-6 of 32 disks, I would naively expect
>>>>>>>> the writes to the gluster area to be roughly 8x faster than to the
>>>>>>>> non-gluster.
>>>>>>>>
>>>>>>>
>>>>>>> I think a better test is to try and write to a file using nfs
>>>>>>> without any gluster to a location that is not inside the brick but
>>>>>>> someother location that is on same disk(s). If you are mounting the
>>>>>>> partition as the brick, then we can write to a file inside .glusterfs
>>>>>>> directory, something like <brick-path>/.glusterfs/<file-to-be-removed-after-test>.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>> I still think we have a speed issue, I can't tell if fuse vs nfs is
>>>>>>>> part of the problem.
>>>>>>>>
>>>>>>>
>>>>>>> I got interested in the post because I read that fuse speed is
>>>>>>> lesser than nfs speed which is counter-intuitive to my understanding. So
>>>>>>> wanted clarifications. Now that I got my clarifications where fuse
>>>>>>> outperformed nfs without sync, we can resume testing as described above and
>>>>>>> try to find what it is. Based on your email-id I am guessing you are from
>>>>>>> Boston and I am from Bangalore so if you are okay with doing this debugging
>>>>>>> for multiple days because of timezones, I will be happy to help. Please be
>>>>>>> a bit patient with me, I am under a release crunch but I am very curious
>>>>>>> with the problem you posted.
>>>>>>>
>>>>>>> Was there anything useful in the profiles?
>>>>>>>>
>>>>>>>
>>>>>>> Unfortunately profiles didn't help me much, I think we are
>>>>>>> collecting the profiles from an active volume, so it has a lot of
>>>>>>> information that is not pertaining to dd so it is difficult to find the
>>>>>>> contributions of dd. So I went through your post again and found something
>>>>>>> I didn't pay much attention to earlier i.e. oflag=sync, so did my own tests
>>>>>>> on my setup with FUSE so sent that reply.
>>>>>>>
>>>>>>>
>>>>>>>>
>>>>>>>> Pat
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> On 05/10/2017 12:15 PM, Pranith Kumar Karampuri wrote:
>>>>>>>>
>>>>>>>> Okay good. At least this validates my doubts. Handling O_SYNC in
>>>>>>>> gluster NFS and fuse is a bit different.
>>>>>>>> When application opens a file with O_SYNC on fuse mount then each
>>>>>>>> write syscall has to be written to disk as part of the syscall where as in
>>>>>>>> case of NFS, there is no concept of open. NFS performs write though a
>>>>>>>> handle saying it needs to be a synchronous write, so write() syscall is
>>>>>>>> performed first then it performs fsync(). so an write on an fd with O_SYNC
>>>>>>>> becomes write+fsync. I am suspecting that when multiple threads do this
>>>>>>>> write+fsync() operation on the same file, multiple writes are batched
>>>>>>>> together to be written do disk so the throughput on the disk is increasing
>>>>>>>> is my guess.
>>>>>>>>
>>>>>>>> Does it answer your doubts?
>>>>>>>>
>>>>>>>> On Wed, May 10, 2017 at 9:35 PM, Pat Haley <phaley at mit.edu> wrote:
>>>>>>>>
>>>>>>>>>
>>>>>>>>> Without the oflag=sync and only a single test of each, the FUSE is
>>>>>>>>> going faster than NFS:
>>>>>>>>>
>>>>>>>>> FUSE:
>>>>>>>>> mseas-data2(dri_nascar)% dd if=/dev/zero count=4096 bs=1048576
>>>>>>>>> of=zeros.txt conv=sync
>>>>>>>>> 4096+0 records in
>>>>>>>>> 4096+0 records out
>>>>>>>>> 4294967296 bytes (4.3 GB) copied, 7.46961 s, 575 MB/s
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> NFS
>>>>>>>>> mseas-data2(HYCOM)% dd if=/dev/zero count=4096 bs=1048576
>>>>>>>>> of=zeros.txt conv=sync
>>>>>>>>> 4096+0 records in
>>>>>>>>> 4096+0 records out
>>>>>>>>> 4294967296 bytes (4.3 GB) copied, 11.4264 s, 376 MB/s
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> On 05/10/2017 11:53 AM, Pranith Kumar Karampuri wrote:
>>>>>>>>>
>>>>>>>>> Could you let me know the speed without oflag=sync on both the
>>>>>>>>> mounts? No need to collect profiles.
>>>>>>>>>
>>>>>>>>> On Wed, May 10, 2017 at 9:17 PM, Pat Haley <phaley at mit.edu> wrote:
>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Here is what I see now:
>>>>>>>>>>
>>>>>>>>>> [root at mseas-data2 ~]# gluster volume info
>>>>>>>>>>
>>>>>>>>>> Volume Name: data-volume
>>>>>>>>>> Type: Distribute
>>>>>>>>>> Volume ID: c162161e-2a2d-4dac-b015-f31fd89ceb18
>>>>>>>>>> Status: Started
>>>>>>>>>> Number of Bricks: 2
>>>>>>>>>> Transport-type: tcp
>>>>>>>>>> Bricks:
>>>>>>>>>> Brick1: mseas-data2:/mnt/brick1
>>>>>>>>>> Brick2: mseas-data2:/mnt/brick2
>>>>>>>>>> Options Reconfigured:
>>>>>>>>>> diagnostics.count-fop-hits: on
>>>>>>>>>> diagnostics.latency-measurement: on
>>>>>>>>>> nfs.exports-auth-enable: on
>>>>>>>>>> diagnostics.brick-sys-log-level: WARNING
>>>>>>>>>> performance.readdir-ahead: on
>>>>>>>>>> nfs.disable: on
>>>>>>>>>> nfs.export-volumes: off
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> On 05/10/2017 11:44 AM, Pranith Kumar Karampuri wrote:
>>>>>>>>>>
>>>>>>>>>> Is this the volume info you have?
>>>>>>>>>>
>>>>>>>>>> >* [root at mseas-data2 <http://www.gluster.org/mailman/listinfo/gluster-users> ~]# gluster volume info
>>>>>>>>>> *>>* Volume Name: data-volume
>>>>>>>>>> *>* Type: Distribute
>>>>>>>>>> *>* Volume ID: c162161e-2a2d-4dac-b015-f31fd89ceb18
>>>>>>>>>> *>* Status: Started
>>>>>>>>>> *>* Number of Bricks: 2
>>>>>>>>>> *>* Transport-type: tcp
>>>>>>>>>> *>* Bricks:
>>>>>>>>>> *>* Brick1: mseas-data2:/mnt/brick1
>>>>>>>>>> *>* Brick2: mseas-data2:/mnt/brick2
>>>>>>>>>> *>* Options Reconfigured:
>>>>>>>>>> *>* performance.readdir-ahead: on
>>>>>>>>>> *>* nfs.disable: on
>>>>>>>>>> *>* nfs.export-volumes: off
>>>>>>>>>>
>>>>>>>>>> *
>>>>>>>>>>
>>>>>>>>>> I copied this from old thread from 2016. This is distribute
>>>>>>>>>> volume. Did you change any of the options in between?
>>>>>>>>>>
>>>>>>>>>> --
>>>>>>>>>>
>>>>>>>>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
>>>>>>>>>> Pat Haley Email: phaley at mit.edu
>>>>>>>>>> Center for Ocean Engineering Phone: (617) 253-6824
>>>>>>>>>> Dept. of Mechanical Engineering Fax: (617) 253-8125
>>>>>>>>>> MIT, Room 5-213 http://web.mit.edu/phaley/www/
>>>>>>>>>> 77 Massachusetts Avenue
>>>>>>>>>> Cambridge, MA 02139-4301
>>>>>>>>>>
>>>>>>>>>> --
>>>>>>>>> Pranith
>>>>>>>>>
>>>>>>>>> --
>>>>>>>>>
>>>>>>>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
>>>>>>>>> Pat Haley Email: phaley at mit.edu
>>>>>>>>> Center for Ocean Engineering Phone: (617) 253-6824
>>>>>>>>> Dept. of Mechanical Engineering Fax: (617) 253-8125
>>>>>>>>> MIT, Room 5-213 http://web.mit.edu/phaley/www/
>>>>>>>>> 77 Massachusetts Avenue
>>>>>>>>> Cambridge, MA 02139-4301
>>>>>>>>>
>>>>>>>>> --
>>>>>>>> Pranith
>>>>>>>>
>>>>>>>> --
>>>>>>>>
>>>>>>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
>>>>>>>> Pat Haley Email: phaley at mit.edu
>>>>>>>> Center for Ocean Engineering Phone: (617) 253-6824
>>>>>>>> Dept. of Mechanical Engineering Fax: (617) 253-8125
>>>>>>>> MIT, Room 5-213 http://web.mit.edu/phaley/www/
>>>>>>>> 77 Massachusetts Avenue
>>>>>>>> Cambridge, MA 02139-4301
>>>>>>>>
>>>>>>>> --
>>>>>>> Pranith
>>>>>>>
>>>>>>> --
>>>>>>>
>>>>>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
>>>>>>> Pat Haley Email: phaley at mit.edu
>>>>>>> Center for Ocean Engineering Phone: (617) 253-6824
>>>>>>> Dept. of Mechanical Engineering Fax: (617) 253-8125
>>>>>>> MIT, Room 5-213 http://web.mit.edu/phaley/www/
>>>>>>> 77 Massachusetts Avenue
>>>>>>> Cambridge, MA 02139-4301
>>>>>>>
>>>>>>> --
>>>>>> Pranith
>>>>>>
>>>>>> --
>>>>>>
>>>>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
>>>>>> Pat Haley Email: phaley at mit.edu
>>>>>> Center for Ocean Engineering Phone: (617) 253-6824
>>>>>> Dept. of Mechanical Engineering Fax: (617) 253-8125
>>>>>> MIT, Room 5-213 http://web.mit.edu/phaley/www/
>>>>>> 77 Massachusetts Avenue
>>>>>> Cambridge, MA 02139-4301
>>>>>>
>>>>>> --
>>>>> Pranith
>>>>>
>>>>> --
>>>>>
>>>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
>>>>> Pat Haley Email: phaley at mit.edu
>>>>> Center for Ocean Engineering Phone: (617) 253-6824
>>>>> Dept. of Mechanical Engineering Fax: (617) 253-8125
>>>>> MIT, Room 5-213 http://web.mit.edu/phaley/www/
>>>>> 77 Massachusetts Avenue
>>>>> Cambridge, MA 02139-4301
>>>>>
>>>>> --
>>>> Pranith
>>>>
>>>> --
>>>>
>>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
>>>> Pat Haley Email: phaley at mit.edu
>>>> Center for Ocean Engineering Phone: (617) 253-6824
>>>> Dept. of Mechanical Engineering Fax: (617) 253-8125
>>>> MIT, Room 5-213 http://web.mit.edu/phaley/www/
>>>> 77 Massachusetts Avenue
>>>> Cambridge, MA 02139-4301
>>>>
>>>>
>>>
>>>
>>> --
>>> Pranith
>>>
>>>
>>> --
>>>
>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
>>> Pat Haley Email: phaley at mit.edu
>>> Center for Ocean Engineering Phone: (617) 253-6824
>>> Dept. of Mechanical Engineering Fax: (617) 253-8125
>>> MIT, Room 5-213 http://web.mit.edu/phaley/www/
>>> 77 Massachusetts Avenue
>>> Cambridge, MA 02139-4301
>>>
>>>
>>
>>
>> --
>> Pranith
>>
>>
>> --
>>
>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
>> Pat Haley Email: phaley at mit.edu
>> Center for Ocean Engineering Phone: (617) 253-6824
>> Dept. of Mechanical Engineering Fax: (617) 253-8125
>> MIT, Room 5-213 http://web.mit.edu/phaley/www/
>> 77 Massachusetts Avenue
>> Cambridge, MA 02139-4301
>>
>>
>
>
> --
> Pranith
>
>
> --
>
> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
> Pat Haley Email: phaley at mit.edu
> Center for Ocean Engineering Phone: (617) 253-6824
> Dept. of Mechanical Engineering Fax: (617) 253-8125
> MIT, Room 5-213 http://web.mit.edu/phaley/www/
> 77 Massachusetts Avenue
> Cambridge, MA 02139-4301
>
>
--
Pranith
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.gluster.org/pipermail/gluster-users/attachments/20170531/b82920ee/attachment.html>
More information about the Gluster-users
mailing list