High Iowait on VMs but not on Server Node

[sahostking]

Hi

When there is high IO wait on KVM Vms but not on the Proxmox Node itself which is around 0.7 always. Although CPU on Proxmox node is around 9.0

CPU is Intel Xeon E5-2620 2.4GHz which has 12 cores.

Now the board can take another CPU should we add another Intel Xeon E5-2620 2.4GHz to it will this solve it.

or even though iowait is low on server and it uses raid10 hw raid with satas should we change to SSDs to solve this?

You recommendations or experience will be appreciated.

 

[udo]

Hi,
how looks your VM-config?

I ask because of the disk-format (raw/qcow2/...), the interface (ide/virtio/scsi), the cache-settings and the VM-OS.

Udo

 

[sahostking]

virtio / qcow2 disks and cache default none as we use hwraid10 with battery backup on writeback

 

[udo]

Hi,
you can try to migrate the disk to raw-format - perhaps your io-wait will be (much) better?? Depends on the kind of IO.

Udo

 

[sahostking]

Web Hostint server hosting alot of domains hence if change it to raw can have significant downtime occur when backups are performed. We went qcow2 for the online backup options.