----- Original Message ----- > From: "Pranith Kumar Karampuri" <pkarampu@xxxxxxxxxx> > To: "Pat Haley" <phaley@xxxxxxx> > Cc: gluster-users@xxxxxxxxxxx, "Steve Postma" <SPostma@xxxxxxxxxxxx> > Sent: Friday, May 12, 2017 11:17:11 PM > Subject: Re: Slow write times to gluster disk > > > > On Sat, May 13, 2017 at 8:44 AM, Pranith Kumar Karampuri < > pkarampu@xxxxxxxxxx > wrote: > > > > > > On Fri, May 12, 2017 at 8:04 PM, Pat Haley < phaley@xxxxxxx > wrote: > > > > > Hi Pranith, > > My question was about setting up a gluster volume on an ext4 partition. I > thought we had the bricks mounted as xfs for compatibility with gluster? > > Oh that should not be a problem. It works fine. > > Just that xfs doesn't have limits for anything, where as ext4 does for things > like hardlinks etc(At least last time I checked :-) ). So it is better to > have xfs. One of the biggest reasons to use XFS IMHO is that most of the testing / large scale deployments(at least that I know of) / etc are done using XFS as a backend. While EXT4 should work I don't think that it has the same level of testing as XFS. -b > > > > > > > > Pat > > > > On 05/11/2017 12:06 PM, Pranith Kumar Karampuri wrote: > > > > > > On Thu, May 11, 2017 at 9:32 PM, Pat Haley < phaley@xxxxxxx > 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@xxxxxxx > 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@xxxxxxx > 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@xxxxxxx > 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@xxxxxxx > 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@xxxxxxx > wrote: > > > > > Here is what I see now: > > [root@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 ~]# 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@xxxxxxx 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@xxxxxxx 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@xxxxxxx 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@xxxxxxx 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@xxxxxxx 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@xxxxxxx 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@xxxxxxx 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 > > > > -- > Pranith > > _______________________________________________ > Gluster-users mailing list > Gluster-users@xxxxxxxxxxx > http://lists.gluster.org/mailman/listinfo/gluster-users _______________________________________________ Gluster-users mailing list Gluster-users@xxxxxxxxxxx http://lists.gluster.org/mailman/listinfo/gluster-users
