Re: performance recommendations

["Pal, Laszlo" <vlad@vlad.hu>]

Hi,

Thank you. If I have to clone, I think I'll just get rid of the
machine and recreate with some other file system. I'm aware, this is
my fault -lack of research and time pressure-, but I think if I can
boot it with the old kernel I'll keep it running as long as it can and
I'll use this time to create another, better designed machine.

Answering your question regarding the ctree, no there is nothing else
in the log but when I check dmesg on the booted rescueCD during mount,
I can see some similar message "btrfs transaction blocked more than
xxx seconds" and the the end "open_ctree", so it seems I really have
some file system corruption as the root cause (maybe created by some
bugs in the old code, or some unexpected reboot)

Thx
Laszlo

On Tue, Feb 16, 2021 at 6:52 PM Leonidas Spyropoulos
<artafinde@gmail.com> wrote:
>
> Hi Laszlo,
>
> On 16/02/21, Pal, Laszlo wrote:
> > Hi,
> >
> > Thank you. So, I've installed a new centos7 with the same
> > configuration, old kernel and using btrfs. Then, upgraded the kernel
> > to 5.11 and all went well, so I thought let's do it on the prod server
> >
> Since this is a VM can you clone the disk / partition and attach it to
> another VM which running a newer kernel and btrfs progs?
>
> This way you can try debugging it without affecting prod server.
>
> > Unfortunately when I boot on 5.11 sysroot mount times out and I have
> > something like this in log
> >
> > btrfs open ctree failed
> So before that `dmesg` doesn't have any relevant logs?
> >
> > Any quick fix for this? I'm able to mount btrfs volume using a rescuCD
> > but I have the same issues, like rm a big file takes 10 minutes....
>
> If you manage to mount the disk in a newer kernel and btrfs progs try
> creating a new file system to take advantage of the new feature (on
> creation) - then migrate the data and follow the recommendations
> mentioned already.
>
> Cheers,
>
> --
> Leonidas Spyropoulos
>
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>