Proxmox 6 with cache=writeback and modern kernels VMs

Jun 28, 2019
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Hi,

I would like your advises regarding enabling or not writeback cache on guest VMs..

We only use modern OSEs like, Centos 7, Centos 8, Ubuntu 16, WIndows 16/19...

What are your recommendations with writeback cache enabled on proxmox guests?

With these modern kernels, will be any chance of a guest OS corruption with writeback enabled after a completely power failure from proxmox node?

Our environment utilizes shared storages with BBU enabled on storage controllers.. the guest virtual disks are stored over these iscsi storages using Shared LVM filesystem.

Proxmox nodes has dual power supply, UPS, Power Generator etc.. but a crash on a node can always happen!!! and since it's a production environment with hundred of VMs, I'm concerned about enabling it or not, because the performance increase inside the VMs has a huge difference!!!
 
Last edited:

guletz

Renowned Member
Apr 19, 2017
1,147
167
68
Brasov, Romania
Our environment utilizes shared storages with BBU enabled on storage controllers.. the guest virtual disks are stored over these iscsi storages using Shared LVM filesystem.
Yes, it is a good chance to lose some data using write-back if you lose the power+the network switches(iscsi) + bbu.
 

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