Proxmox High IO

Mar 4, 2019
Basically I have a HP Proliant DL 160 G6 with: 2 x Xenon L5630 (16 Threads on total), 16 Gb Ram , 1x 4 Tb HDD WD Red.
I installed the Proxmox on the disk, and then I setup 2 VMs: 1 VM with 4 cpu and 7 Gb of RAM ; 1 VM with 11 cpu and 8Gb of RAM.
From start of August I started to having high IO wait as I can see on NETDATA on the 4 cpu VM and on the proxmox graphic too.
What should I do? Should I install the proxmox on a WD 320Gb disk that I have and use this disk only for VMs? Or should I install proxmox on the 320Gb disk and get a disk for each VM?
Miguel de Carvalho
What is that VM doing? If it is doing a lot of IO maybe you need faster disks. But there are other issues to look at.

Maybe the host is swapping and that is interfering with the guest IO. You have pretty much allocated all of your resources, leaving only 1 GB for the host, which is below the minimum recommended for Debian. If you are using ZFS you'll need more than the minimum. Remember, the host has to carry out the actual IO operations that the guests request and it needs some memory to do that.

BTW, a "thread" is not a "cpu". You have 8 actual CPU's, which with Hyperthreading are really 10 or 12 CPU-equivalents depending on workload. So you have also allocated almost all of you cpu-equivalents to one VM. If that VM really uses that many cores, that also may be a problem of not leaving enough resources for the host.

I think your issue isn't really the disks, but that you have not enough CPU & RAM resources for what you are trying to do.
Basically on the lowest VM I have media and nextcloud related things and gerrit. On other VM is where I build android ROMs.
So what do you think that I should do ?
Miguel de Carvalho


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