[SOLVED] proxmox VM IOPs unit of measure

[Maher Khalil]

Hello
I would like to know what measure proxmox use for virtual machine iops.
For example when Samsung disk PM1643 says Random Read is 440k OPS, I can understand that is equal to 440 x 1000 = 440000 IOPS (https://semiconductor.samsung.com/us/ssd/enterprise-ssd/)
So, if I want to use 10% for VM read limit (ops/s) , should I take disk 10% = 10% x 440000 = 44000 IOPS and use it on proxmox or use = 10%x 440k = 44 and use that on proxmox?
I would like to ask also is that IOPs in proxmox is per VM or each gigabyte in VM (like amazon?)

 

[fiona]

Hi,
the value is in operations/requests per second, so you should use 44000 in your example.

 

[Maher Khalil]

Hi,
the value is in operations/requests per second, so you should use 44000 in your example.

So, does that value per VM or Gigabyte, so if VM have 100GB , so I give total 44000 for Proxmox or I give value 44000/100=440 (for example Amazon gives value per GB)?

 

[Dunuin]

IOPS = input/output operations per seconds.
So it"s not related to the capacity.

The bigger question would be where PVE counts the IO. I would guess it's on the virtualization side, so IO read/written to the virtual disk and in that case the IO hitting the actual physical storage could be way higher because of overhead.

 

[Maher Khalil]

IOPS = input/output operations per seconds.
So it"s not related to the capacity.

The bigger question would be where PVE counts the IO. I would guess it's on the virtualization side, so IO read/written to the virtual disk and in that case the IO hitting the actual physical storage could be way higher because of overhead.

I will appreciate if someone from Proxmox stuff can help us understand this part?

 

[fiona]

So, does that value per VM or Gigabyte, so if VM have 100GB , so I give total 44000 for Proxmox or I give value 44000/100=440 (for example Amazon gives value per GB)?

It's operations per second, not operations per second per GB. The setting is for the virtual disk only, not per VM or per gigabyte.

As @Dunuin already suspected, the option is passed to QEMU. Because QEMU virtualizes the block layer for the VM's disk, it knows how many requests the guest issues for the disk and can limit the rate at which those are processed.

 

[Maher Khalil]

Understood
Thank you