>>What rates do you find on your proxmox/ceph cluster for single VMs?
with replicat x3 and 4k block random read/write with big queue depth, I'm around 70000iops read && 40000iops write (by vm disk if iothread is used, the limitation is cpu usage of 1 thread/core by disk) with queue depth=1, I'm around 4000-5000 iops. (because of network latency + cpu latency). This is with client/server with 3ghz intel cpu. ----- Mail original ----- De: "Rainer Krienke" <krie...@uni-koblenz.de> À: "proxmoxve" <pve-user@pve.proxmox.com> Envoyé: Mardi 17 Mars 2020 14:04:22 Objet: [PVE-User] Proxmox with ceph storage VM performance strangeness Hello, I run a pve 6.1-7 cluster with 5 nodes that is attached (via 10Gb Network) to a ceph nautilus cluster with 9 ceph nodes and 144 magnetic disks. The pool with rbd images for disk storage is erasure coded with a 4+2 profile. I ran some performance tests since I noticed that there seems to be a strange limit to the disk read/write rate on a single VM even if the physical machine hosting the VM as well as cluster is in total capable of doing much more. So what I did was to run a bonnie++ as well as a dd read/write test first in parallel on 10 VMs, then on 5 VMs and at last on a single one. A value of "75" for "bo++rd" in the first line below means that each of the 10 bonnie++-processes running on 10 different proxmox VMs in parallel reported in average over all the results a value of 75MBytes/sec for "block read". The ceph-values are the peaks measured by ceph itself during the test run (all rd/wr values in MBytes/sec): VM-count: bo++rd: bo++wr: ceph(rd/wr): dd-rd: dd-wr: ceph(rd/wr): 10 75 42 540/485 55 58 698/711 5 90 62 310/338 47 80 248/421 1 108 114 111/120 130 145 337/165 What I find a little strange is that running many VMs doing IO in parallel I reach a write rate of about 485-711 MBytes/sec. However when running a single VM the maximum is at 120-165 MBytes/sec. Since the whole networking is based on a 10GB infrastructure and an iperf test between a VM and a ceph node reported nearby 10Gb I would expect a higher rate for the single VM. Even if I run a test with 5 VMs on *one* physical host (values not shown above), the results are not far behind the values for 5 VMs on 5 hosts shown above. So the single host seems not to be the limiting factor, but the VM itself is limiting IO. What rates do you find on your proxmox/ceph cluster for single VMs? Does any one have any explanation for this rather big difference or perhaps an idea what to try in order to get higher IO-rates from a single VM? Thank you very much in advance Rainer --------------------------------------------- Here are the more detailed test results for anyone interested: Using bonnie++: 10 VMs (two on each of the 5 hosts) VMs: 4GB RAM, BTRFS, cd /root; bonnie++ -u root Average for each VM: block write: ~42MByte/sec, block read: ~75MByte/sec ceph: total peak: 485MByte/sec write, 540MByte/sec read 5 VMs (one on each of the 5 hosts) 4GB RAM, BTRFS, cd /root; bonnie++ -u root Average for each VM: block write: ~62MByte/sec, block read: ~90MByte/sec ceph: total peak: 338MByte/sec write, 310MByte/sec read 1 VM 4GB RAM, BTRFS, cd /root; bonnie++ -u root Average for VM: block write: ~114 MByte/sec, block read: ~108MByte/sec ceph: total peak: 120 MByte/sec write, 111MByte/sec read Using dd: 10 VMs (two on each of the 5 hosts) VMs: 4GB RAM, write on a ceph based vm-disk "sdb" (rbd) write: dd if=/dev/zero of=/dev/sdb bs=nnn count=kkk conv=fsync status=progress read: dd of=/dev/null if=/dev/sdb bs=nnn count=kkk status=progress Average for each VM: bs=1024k count=12000: dd write: ~58MByte/sec, dd read: ~48MByte/sec bs=4096k count=3000: dd write: ~59MByte/sec, dd read: ~55MByte/sec ceph: total peak: 711MByte/sec write, 698 MByte/sec read 5 VMs (two on each of the 5 hosts) VMs: 4GB RAM, write on a ceph based vm-disk "sdb" (rbd) write: dd if=/dev/zero of=/dev/sdb bs=4096k count=3000 conv=fsync status=progress read: dd of=/dev/null if=/dev/sdb bs=4096k count=3000 status=progress Average for each VM: bs=4096 count=3000: dd write: ~80 MByte/sec, dd read: ~47MByte/sec ceph: total peak: 421MByte/sec write, 248 MByte/sec read 1 VM: 4GB RAM, write on a ceph based vm-disk "sdb" (rbd-device) write: dd if=/dev/zero of=/dev/sdb bs=4096k count=3000 conv=fsync status=progress read: dd of=/dev/null if=/dev/sdb bs=4096k count=3000 status=progress Average for each VM: bs=4096k count=3000: dd write: ~145 MByte/sec, dd read: ~130 MByte/sec ceph: total peak: 165 MByte/sec write, 337 MByte/sec read -- Rainer Krienke, Uni Koblenz, Rechenzentrum, A22, Universitaetsstrasse 1 56070 Koblenz, Web: http://www.uni-koblenz.de/~krienke, Tel: +49261287 1312 PGP: http://www.uni-koblenz.de/~krienke/mypgp.html, Fax: +49261287 1001312 _______________________________________________ pve-user mailing list pve-user@pve.proxmox.com https://pve.proxmox.com/cgi-bin/mailman/listinfo/pve-user _______________________________________________ pve-user mailing list pve-user@pve.proxmox.com https://pve.proxmox.com/cgi-bin/mailman/listinfo/pve-user