[pve-devel] Default cache mode for VM hard drives

[Dietmar Maurer]

Beside, we do not have a storage type for DRBD, so we simply cannot detect this situation
automatically. So I guess you need to set that manually.

Do you use LVM on top of the DRBD device?

> -----Original Message-----
> From: Stanislav German-Evtushenko [mailto:ginermail at gmail.com]
> Sent: Dienstag, 18. November 2014 19:51
> To: Dietmar Maurer
> Cc: Alexandre Derumier; pve-devel at pve.proxmox.com
> Subject: Re: [pve-devel] Default cache mode for VM hard drives
> 
> On Tue, Nov 18, 2014 at 9:45 PM, Dietmar Maurer <dietmar at proxmox.com>
> wrote:
> > So this is a DRBD bug?
> >
> > Lars doesn't see this as a bug. See also says that software raid behaves in the
> > same way
> 
> IMHO, software RAID is also buggy unless you disable write cache inside drives.
> That is
> why we never recommend software raid..
> 
> That's also true. High-end hardware raid controllers (at least Dell ones) do not
> use (disable) drive caches by default otherwise they wouldn't survive power cut
> offs.