[ovirt-users] Re: Poor gluster performances over 10Gbps network

Hi Mathieu,                     How are you measuring the Gluster disk performance? also using dd you should use the oflag=dsync to avoid buffer caching. Regards, Paul S ------------------------------------------------------------------------ *From:* Mathieu Valois <mvalois(a)teicee.com&gt; *Sent:* 08 September 2021 10:12 *To:* users <users(a)ovirt.org&gt; *Subject:* [ovirt-users] Poor gluster performances over 10Gbps network *Caution External Mail:* Do not click any links or open any attachments unless you trust the sender and know that the content is safe. Sorry for double post but I don't know if this mail has been received. Hello everyone, I know this issue was already treated on this mailing list. However none of the proposed solutions is satisfying me. Here is my situation : I've got 3 hyperconverged gluster ovirt nodes, with 6 network interfaces, bounded in bunches of 2 (management, VMs and gluster). The gluster network is on a dedicated bound where the 2 interfaces are directly connected to the 2 other ovirt nodes. Gluster is apparently using it : # gluster volume status vmstore Status of volume: vmstore Gluster process                             TCP Port  RDMA Port  Online  Pid ------------------------------------------------------------------------------ Brick gluster-ov1:/gluster_bricks /vmstore/vmstore                            49152 0          Y       3019 Brick gluster-ov2:/gluster_bricks /vmstore/vmstore                            49152 0          Y       3009 Brick gluster-ov3:/gluster_bricks /vmstore/vmstore where 'gluster-ov{1,2,3}' are domain names referencing nodes in the gluster network. This networks has 10Gbps capabilities : # iperf3 -c gluster-ov3 Connecting to host gluster-ov3, port 5201 [  5] local 10.20.0.50 port 46220 connected to 10.20.0.51 port 5201 [ ID] Interval           Transfer     Bitrate Retr  Cwnd [  5]   0.00-1.00   sec  1.16 GBytes  9.92 Gbits/sec 17    900 KBytes [  5]   1.00-2.00   sec  1.15 GBytes  9.90 Gbits/sec 0    900 KBytes [  5]   2.00-3.00   sec  1.15 GBytes  9.90 Gbits/sec 4    996 KBytes [  5]   3.00-4.00   sec  1.15 GBytes  9.90 Gbits/sec 1    996 KBytes [  5]   4.00-5.00   sec  1.15 GBytes  9.89 Gbits/sec 0    996 KBytes [  5]   5.00-6.00   sec  1.15 GBytes  9.90 Gbits/sec 0    996 KBytes [  5]   6.00-7.00   sec  1.15 GBytes  9.90 Gbits/sec 0    996 KBytes [  5]   7.00-8.00   sec  1.15 GBytes  9.91 Gbits/sec 0    996 KBytes [  5]   8.00-9.00   sec  1.15 GBytes  9.90 Gbits/sec 0    996 KBytes [  5]   9.00-10.00  sec  1.15 GBytes  9.90 Gbits/sec 0    996 KBytes - - - - - - - - - - - - - - - - - - - - - - - - - [ ID] Interval           Transfer     Bitrate         Retr [  5]   0.00-10.00  sec  11.5 GBytes  9.90 Gbits/sec 22             sender [  5]   0.00-10.04  sec  11.5 GBytes  9.86 Gbits/sec                  receiver iperf Done. However, VMs stored on the vmstore gluster volume has poor write performances, oscillating between 100KBps and 30MBps. I almost always observe a write spike (180Mbps) at the beginning until around 500MB written, then it drastically falls at 10MBps, sometimes even less (100KBps). Hypervisors have 32 threads (2 sockets, 8 cores per socket, 2 threads per core). Here is the volume settings : Volume Name: vmstore Type: Replicate Volume ID: XXX Status: Started Snapshot Count: 0 Number of Bricks: 1 x 3 = 3 Transport-type: tcp Bricks: Brick1: gluster-ov1:/gluster_bricks/vmstore/vmstore Brick2: gluster-ov2:/gluster_bricks/vmstore/vmstore Brick3: gluster-ov3:/gluster_bricks/vmstore/vmstore Options Reconfigured: performance.io-thread-count: 32 # was 16 by default. cluster.granular-entry-heal: enable storage.owner-gid: 36 storage.owner-uid: 36 cluster.lookup-optimize: off server.keepalive-count: 5 server.keepalive-interval: 2 server.keepalive-time: 10 server.tcp-user-timeout: 20 network.ping-timeout: 30 server.event-threads: 4 client.event-threads: 8 # was 4 by default cluster.choose-local: off features.shard: on cluster.shd-wait-qlength: 10000 cluster.shd-max-threads: 8 cluster.locking-scheme: granular cluster.data-self-heal-algorithm: full cluster.server-quorum-type: server cluster.quorum-type: auto cluster.eager-lock: enable performance.strict-o-direct: on network.remote-dio: off performance.low-prio-threads: 32 performance.io-cache: off performance.read-ahead: off performance.quick-read: off auth.allow: * user.cifs: off storage.fips-mode-rchecksum: on transport.address-family: inet nfs.disable: on performance.client-io-threads: on When I naively write directly on the logical volume, which is mounted on a material RAID5 3-disks array, I have interesting performances: # dd if=/dev/zero of=a bs=4M count=2048 2048+0 records in 2048+0 records out 8589934592 bytes (8.6 GB, 8.0 GiB) copied, 17.2485 s, 498 MB/s #urandom gives around 200MBps Moreover, hypervisors have SSD which have been configured as lvcache, but I'm unsure how to test it efficiently. I can't find where is the problem, as every piece of the chain is apparently doing well ... Thanks anyone for helping me :) -- téïcée <https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.tei... *Mathieu Valois* Bureau Caen: Quartier Kœnig - 153, rue Géraldine MOCK - 14760 Bretteville-sur-Odon Bureau Vitré: Zone de la baratière - 12, route de Domalain - 35500 Vitré 02 72 34 13 20 | www.teicee.com <https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.tei... téïcée sur facebook <https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.fac... téïcée sur twitter <https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Ftwitter... téïcée sur linkedin <https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.lin... téïcée sur viadeo <https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Ffr.viad... 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