PVE becomes unstable with Windows Server 2022 et Write-Back disks

[Yannick ITPRO]

Good morning,

I have a problem migrating from VMware to ProxMox:

In order to obtain performance equivalent to VMware and follow ProxMox best practices:
https://pve.proxmox.com/wiki/Windows_2022_guest_best_practices I use the HDDs of my Windows Server 2022 VMs in Write-Back mode.

My biggest problem is that, during my benchmark tests with CrystalDiskMark, little by little the "IO delay" increases enormously so that my VM freezes and worse: my PVE becomes unstable and my other VMs are impacted!

NB: This happens during the test phase in writing, no problem in reading.
No problem if I use Write-Back (unsafe) mode, good performance but not recommended in production.
No problems with other modes but performance is worse.

Characteristics of my HDDs (smartctl -a /dev/sda):
Model Family: Seagate FireCuda 2.5
Device Model: ST2000LX001-1RG174

Thank you in advance for your help.

Yann.

 

[leesteken]

NB: This happens during the test phase in writing, no problem in reading.
No problem if I use Write-Back (unsafe) mode, good performance but not recommended in production.
No problems with other modes but performance is worse.

Characteristics of my HDDs (smartctl -a /dev/sda):
Model Family: Seagate FireCuda 2.5
Device Model: ST2000LX001-1RG174

This is an SMR drive and it will get very slow when writing to it without giving it time to reorganize the data while being idle. If you want sustained good write performance then replace it with a CMR drive. If you use ZFS, you might even get errors because such drives get so slow that ZFS assumes it is failing.

 

[Yannick ITPRO]

This is an SMR drive and it will get very slow when writing to it without giving it time to reorganize the data while being idle. If you want sustained good write performance then replace it with a CMR drive. If you use ZFS, you might even get errors because such drives get so slow that ZFS assumes it is failing.

Thank you very much Leetstekeen for your quick and precise response !
(I'm only using the standard lvm/lvm-thin)

If I understood correctly there is no way to play on certain parameters
I always thought that SSD technology was more efficient than traditional disks.
I'm going to look to buy another HDD even if I'm a little disappointed to have to buy more equipment
(any recommendations on models known to be efficient ?)

 

[leesteken]

If I understood correctly there is no way to play on certain parameters

Maybe it works well enough with write-back cache or when you are not running benchmarks?

I'm going to look to buy another HDD even if I'm a little disappointed to have to buy more equipment

I also learned to search and read this forum before buying hardware. Turns out that enterprise drives (HDD and SSD) do have advantages, especially when you are using then with multiple (virtual) machines worth of I/O at the same time.