On 11/24/2017 06:41 AM, Sahina Bose wrote: > > > On Thu, Nov 23, 2017 at 4:56 PM, Jiří Sléžka <jiri.slezka@xxxxxx > <mailto:jiri.slezka@xxxxxx>> wrote: > > Hi, > > On 11/22/2017 07:30 PM, Nir Soffer wrote: > > On Mon, Nov 20, 2017 at 5:22 PM Jiří Sléžka <jiri.slezka@xxxxxx <mailto:jiri.slezka@xxxxxx> > > <mailto:jiri.slezka@xxxxxx <mailto:jiri.slezka@xxxxxx>>> wrote: > > > > Hi, > > > > I am trying realize why is exporting of vm to export storage on > > glusterfs such slow. > > > > I am using oVirt and RHV, both instalations on version 4.1.7. > > > > Hosts have dedicated nics for rhevm network - 1gbps, data > storage itself > > is on FC. > > > > GlusterFS cluster lives separate on 4 dedicated hosts. It has > slow disks > > but I can achieve about 200-400mbit throughput in other > applications (we > > are using it for "cold" data, backups mostly). > > > > I am using this glusterfs cluster as backend for export > storage. When I > > am exporting vm I can see only about 60-80mbit throughput. > > > > What could be the bottleneck here? > > > > Could it be qemu-img utility? > > > > vdsm 97739 0.3 0.0 354212 29148 ? S<l 15:43 0:06 > > /usr/bin/qemu-img convert -p -t none -T none -f raw > > > /rhev/data-center/2ff6d0ee-a10b-473d-b77c-be9149945f5f/ff3cd56a-1005-4426-8137-8f422c0b47c1/images/ba42cbcc-c068-4df8-af3d-00f2077b1e27/c57acd5f-d6cf-48cc-ad0c-4a7d979c0c1e > > -O raw > > > /rhev/data-center/mnt/glusterSD/10.20.30.41:_rhv__export/81094499-a392-4ea2-b081-7c6288fbb636/images/ba42cbcc-c068-4df8-af3d-00f2077b1e27/c57acd5f-d6cf-48cc-ad0c-4a7d979c0c1e > > > > Any idea how to make it work faster or what throughput should I > > expected? > > > > > > gluster storage operations are using fuse mount - so every write: > > - travel to the kernel > > - travel back to the gluster fuse helper process > > - travel to all 3 replicas - replication is done on client side > > - return to kernel when all writes succeeded > > - return to caller > > > > So gluster will never set any speed record. > > > > Additionally, you are copying from raw lv on FC - qemu-img cannot do > > anything > > smart and avoid copying unused clusters. Instead if copies > gigabytes of > > zeros > > from FC. > > ok, it does make sense > > > However 7.5-10 MiB/s sounds too slow. > > > > I would try to test with dd - how much time it takes to copy > > the same image from FC to your gluster storage? > > > > dd > > if=/rhev/data-center/2ff6d0ee-a10b-473d-b77c-be9149945f5f/ff3cd56a-1005-4426-8137-8f422c0b47c1/images/ba42cbcc-c068-4df8-af3d-00f2077b1e27/c57acd5f-d6cf-48cc-ad0c-4a7d979c0c1e > > of=/rhev/data-center/mnt/glusterSD/10.20.30.41:_rhv__export/81094499-a392-4ea2-b081-7c6288fbb636/__test__ > > bs=8M oflag=direct status=progress > > unfrotunately dd performs the same > > 1778384896 bytes (1.8 GB) copied, 198.565265 s, 9.0 MB/s > > > > If dd can do this faster, please ask on qemu-discuss mailing list: > > https://lists.nongnu.org/mailman/listinfo/qemu-discuss > <https://lists.nongnu.org/mailman/listinfo/qemu-discuss> > > > > If both give similar results, I think asking in gluster mailing list > > about this can help. Maybe your gluster setup can be optimized. > > ok, this is definitly on the gluster side. Thanks for your guidance. > > I will investigate the gluster side and also will try Export on NFS > share. > > > [Adding gluster users ml] > > Please provide "gluster volume info" output for the rhv_export gluster > volume and also volume profile details (refer to earlier mail from Shani > on how to run this) while performing the dd operation above. you can find all this output on https://pastebin.com/sBK01VS8 as mentioned in other posts. Gluster cluster uses really slow (green) disks but without direct io it can achieve throughput around 400mbit/s. This storage is used mostly for backup purposes. It is not used as a vm storage. In my case it would be nice not to use direct io in export case but I understand why it might not be wise. Cheers, Jiri > > > > > Cheers, > > Jiri > > > > > > Nir > > > > > > > > Cheers, > > > > Jiri > > > > > > _______________________________________________ > > Users mailing list > > Users@xxxxxxxxx <mailto:Users@xxxxxxxxx> > <mailto:Users@xxxxxxxxx <mailto:Users@xxxxxxxxx>> > > http://lists.ovirt.org/mailman/listinfo/users > <http://lists.ovirt.org/mailman/listinfo/users> > > > > > > _______________________________________________ > Users mailing list > Users@xxxxxxxxx <mailto:Users@xxxxxxxxx> > http://lists.ovirt.org/mailman/listinfo/users > <http://lists.ovirt.org/mailman/listinfo/users> > >
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