On Wed, Sep 25, 2019 at 2:44 PM Tony Brian Albers <tba@kb.dk> wrote:
Guys,
Just for info, this is what I'm getting on a VM that is on shared storage via NFSv3:
--------------------------snip---------------------- [root@proj-000 ~]# time dd if=/dev/zero of=testfile bs=4096 count=1000000 1000000+0 records in 1000000+0 records out 4096000000 bytes (4.1 GB) copied, 18.0984 s, 226 MB/s
real 0m18.171s user 0m1.077s sys 0m4.303s [root@proj-000 ~]# --------------------------snip----------------------
my /etc/exports: /data/ovirt *(rw,sync,no_subtree_check,all_squash,anonuid=36,anongid=36)
and output from 'mount' on one of the hosts:
sto-001.kac.lokalnet:/data/ovirt on /rhev/data-center/mnt/sto- 001.kac.lokalnet:_data_ovirt type nfs (rw,relatime,vers=3,rsize=1048576,wsize=1048576,namlen=255,soft,nolock, nosharecache,proto=tcp,timeo=600,retrans=6,sec=sys,mountaddr=172.16.216 .41,mountvers=3,mountport=20048,mountproto=udp,local_lock=all,addr=172. 16.216.41)
Worth to compare mount options with the slow shared NFSv4 mount. Window size tuning can be found at bottom of [1], although its relating to NFSv3, it could be relevant to v4 as well. [1] https://www.ovirt.org/develop/troubleshooting-nfs-storage-issues.html
connected via single 10gbit ethernet. Storage on NFS server is 8 x 4TB SATA disks in RAID10. NFS server is running CentOS 7.6.
Maybe you can get some inspiration from this.
/tony
On Wed, 2019-09-25 at 09:59 +0000, Vrgotic, Marko wrote:
Dear Strahil, Amit,
Thank you for the suggestion. Test result with block size 4096: Network storage: avshared: [root@mpoludctest4udc-1 ~]# dd if=/dev/zero of=/tmp/test2.img bs=4096 count=100000 oflag=dsync 100000+0 records in 100000+0 records out 409600000 bytes (410 MB) copied, 275.522 s, 1.5 MB/s
Local storage:
avlocal2: [root@mpollocalcheck22 ~]# dd if=/dev/zero of=/tmp/test2.img bs=4096 count=100000 oflag=dsync 100000+0 records in 100000+0 records out 409600000 bytes (410 MB) copied, 53.093 s, 7.7 MB/s 10:38 avlocal3: [root@mpollocalcheck3 ~]# dd if=/dev/zero of=/tmp/test2.img bs=4096 count=100000 oflag=dsync 100000+0 records in 100000+0 records out 409600000 bytes (410 MB) copied, 46.0392 s, 8.9 MB/s
As Amit suggested, I am also going to execute same tests on the BareMetals and between BareMetal and NFS to compare results.
— — — Met vriendelijke groet / Kind regards,
Marko Vrgotic
From: Strahil <hunter86_bg@yahoo.com> Date: Tuesday, 24 September 2019 at 19:10 To: "Vrgotic, Marko" <M.Vrgotic@activevideo.com>, Amit <abawer@redhat .com> Cc: users <users@ovirt.org> Subject: Re: [ovirt-users] Re: Super Low VM disk IO via Shared Storage
Why don't you try with 4096 ? Most block devices have a blcok size of 4096 and anything bellow is slowing them down. Best Regards, Strahil Nikolov On Sep 24, 2019 17:40, Amit Bawer <abawer@redhat.com> wrote: have you reproduced performance issue when checking this directly with the shared storage mount, outside the VMs?
On Tue, Sep 24, 2019 at 4:53 PM Vrgotic, Marko <M.Vrgotic@activevideo .com> wrote: Dear oVirt,
I have executed some tests regarding IO disk speed on the VMs, running on shared storage and local storage in oVirt.
Results of the tests on local storage domains: avlocal2: [root@mpollocalcheck22 ~]# dd if=/dev/zero of=/tmp/test2.img bs=512 count=100000 oflag=dsync 100000+0 records in 100000+0 records out 51200000 bytes (51 MB) copied, 45.9756 s, 1.1 MB/s
avlocal3: [root@mpollocalcheck3 ~]# dd if=/dev/zero of=/tmp/test2.img bs=512 count=100000 oflag=dsync 100000+0 records in 100000+0 records out 51200000 bytes (51 MB) copied, 43.6179 s, 1.2 MB/s
Results of the test on shared storage domain: avshared: [root@mpoludctest4udc-1 ~]# dd if=/dev/zero of=/tmp/test2.img bs=512 count=100000 oflag=dsync 100000+0 records in 100000+0 records out 51200000 bytes (51 MB) copied, 283.499 s, 181 kB/s
Why is it so low? Is there anything I can do to tune, configure VDSM or other service to speed this up? Any advice is appreciated.
Shared storage is based on Netapp with 20Gbps LACP path from Hypervisor to Netapp volume, and set to MTU 9000. Used protocol is NFS4.0. oVirt is 4.3.4.3 SHE.
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