Proxmox raid10 4 hdd 20 windows vms, very slow.

[vfiuchcikicshuusrch]

Hi!
I try to make multi os remote desktops.
32 x Xeon 2665 v2
96 Gb RAM
4 x 1TB Hdd (write speed 180mb/s) ZFS RAID10 (write speed ~400mb/s)
20 VMs whit SCSI hdd (discard, IO Thread, SSD Emulation, and speed limits are set for every vm)

this config work very slow. very high IO Delay.

Can any one ask which config will work fine for this case 20 different vms.

 

[Stefan_R]

You can try setting the cache mode for your VMs to different values and see if that helps (Hardware -> Hard Disk -> Cache, then reboot the VM). Also make sure you're using the latest VirtIO drivers and the VirtIO-SCSI controller for your VMs.

In general, 4 spinning disks for 20 VMs will definitely be on the slower side.

 

[mmenaz]

Hi!
I try to make multi os remote desktops.
32 x Xeon 2665 v2
96 Gb RAM
4 x 1TB Hdd (write speed 180mb/s) ZFS RAID10 (write speed ~400mb/s)
20 VMs whit SCSI hdd (discard, IO Thread, SSD Emulation, and speed limits are set for every vm)

this config work very slow. very high IO Delay.

Can any one ask which config will work fine for this case 20 different vms.

no ZIL/SLOG with datacenter grade (possible with powerloss data protection) SSD dedicated device? You do need it to have sync writes be much faster.
https://pve.proxmox.com/wiki/ZFS_on_Linux
"Add cache and log to an existing pool"
If you can have a (datacenter grade) NVMe device instead of sata ssd even better.

 

[guletz]

Hi,

Your server is far away from what do you need for 20 VMs. At minimum 20 VM x 4 GB = 80 GB. So only 16 GB will be available for zfs (too low).

You do need it to have sync writes be much faster.

Dedicated SLOG will improve only the latency not the bandwith.

Good luck / Bafta !

 

[mmenaz]

Hi,

Your server is far away from what do you need for 20 VMs. At minimum 20 VM x 4 GB = 80 GB. So only 16 GB will be available for zfs (too low).




Dedicated SLOG will improve only the latency not the bandwith.

Good luck / Bafta !

OP says "very high IO Delay", so I think that SLOG will improve a lot in this situation. In any case without SLOG performances in general are really worse than with it.

 

[guletz]

OP says "very high IO Delay", so I think that SLOG will improve a lot in this situation. In any case without SLOG performances in general are really worse than with it.

Hi,

Without some figure, what you say is only a speculation. arc_summary output can show the true. As general idea, most of the time the win os, are not have so many sync write io (if not use DB). Mostly are async io. I also think is very unlikely to have a DB on each VM.

Good luck / Bafta!

 

[vfiuchcikicshuusrch]

I added ZIL nvme, but it only accelerated the numbers of parameters, but not the server performance itself. The delays remained almost at the same level!
When I installed nvme storage the server began to crash.

Now, for testing, I install 2 ssd into RAID0 and perfomance was nice for 25 virtual windows10 machines. But I wan't some more. =)