On 10/10/24 09:29, Roland wrote:
thank you for clearing things up.
>Which means that the test case is actually invalid; you either would
need drop O_DIRECT or modify the buffer
>after write() to arrive with a valid example.
ok, but what about running virtual machines in O_DIRECT mode on top of
mdraid then ?
https://forum.proxmox.com/threads/zfs-on-debian-or-mdadm-softraid-
stability-and-reliability-of-zfs.116871/post-505697
The example quoted is this:
> Take a virtual machine, give it a disk - put the image on a software
> raid and tell qemu to disable caching (iow. use O_DIRECT, because the
> guest already does caching anyway).
> Run linux in the VM, add part of the/a disk on the raid as swap, and
> cause the guest to start swapping a lot.
And then ending up with data corruption on MD. Which I really would love
to see reproduced, especially with recent kernels, as there is a lot of
vagueness around it (add part of the disk on the raid as swap? How?
In the host? On the guest?).
Hint: we (SUSE) have a bugzilla.suse.com. And if someone would be
reproducing that with, say, OpenSUSE Tumbleweed and open a bugzilla
someone on this list would be more than happy to have a look and do
a proper debugging here. There are a lot of things which have changed
since 2017 (Stable pages? Anyone?), so it might be that the cited issue
simply is not reproducible anymore.
Cheers,
Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
hare@xxxxxxx +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich
