ZVOL with volblocksize=64k+ results in data corruption [was Re: Resolving errors with ZVOL-s]

[Wiktor Niesiobedzki]

On Fri, 22 Sep 2017 at 10:48, Andriy Gapon <avg at freebsd.org> wrote:

> On 21/09/2017 23:00, Wiktor Niesiobedzki wrote:
> > I've conducted additional tests. It looks like when I create volumes with
> > following commands:
> > # zfs create -V50g -o volmode=dev -o volblocksize=64k -o compression=off
> -o
> > com.sun:auto-snapshot=false tank/test
> > # zfs create -V50g -o volmode=dev -o volblocksize=128k -o compression=off
> > -o com.sun:auto-snapshot=false tank/test
> >
> > I'm able to get checksum errors quite reliably in 2-12h of normal work of
> > the volume. I tested also different volbocksizes:
> > # zfs create -V50g -o volmode=dev -o volblocksize=32k -o compression=off
> -o
> > com.sun:auto-snapshot=false tank/test
> > # zfs create -V50g -o volmode=dev -o volblocksize=8k -o compression=off
> -o
> > com.sun:auto-snapshot=false tank/test
> > # zfs create -V50g -o volmode=dev -o volblocksize=4k -o compression=off
> -o
> > com.sun:auto-snapshot=false tank/test
> >
> > And gave them more than 24h of work with no apparent errors (I also moved
> > other volumes to 4k and they did not show any checksum errors for more
> than
> > 2 weeks).
> >
> > I was running with volblocksize=128k from January this year. The problem
> > started to appear only after I updated from 11.0 to 11.1.
> >
> > Should I file bug report for this? What additional information should I
> > gather?
>
> Are you able to patch your version of FreeBSD?
> Could you please try https://svnweb.freebsd.org/changeset/base/323918
> and see if it makes things better?
>

Yes, I'll give it a try for a weekend and let you know about the result.


Cheers,

Wiktor