[OpenAFS] Problems with power outages

[Jeffrey Altman]

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Karl M. Davis wrote:
> Hey there all,
>=20
> =20
>=20
> I just recently set up the Debian openafs 1.4.4 packages on an Ubuntu
> server box, running in a virtual machine.  It=E2=80=99s monsoon season =
here in
> Tucson and we=E2=80=99ve had a couple of long power outages and problem=
s with
> the UPS.  Both times the server has gone done unexpectedly, AFS didn=E2=
=80=99t
> come back up correctly.  The symptoms I note are that =E2=80=9Cls /afs=E2=
=80=9D returns
> empty on the server and the Windows client can=E2=80=99t connect.
>
> For whatever reason, the thing that has fixed it both times is running
> =E2=80=9Cfs checkvolumes=E2=80=9D.  Of course, =E2=80=9Cfs checkvolumes=
=E2=80=9D segfaults when I run
> it, but if I reboot after that, everything comes back up fine, clients
> can connect, and further =E2=80=9Cfs checkvolumes=E2=80=9D don=E2=80=99=
t segfault.  Rebooting
> before running that specific command (with the segfault) does
> nothing=E2=80=94=E2=80=9Cls /afs=E2=80=9D still returns empty.
>
>=20
> So=E2=80=A6 a couple of questions:
>=20
> How do I ensure AFS can survive a power outage/unexpected poweroff
> without getting borked?
>=20
> If it does get borked, why would a segfaulting =E2=80=9Cfs checkvolumes=
=E2=80=9D fix things?

fs checkvolumes doesn't really check anything.  It instructs the AFS
cache manager to invalidate its knowledge of all of the volume location
information thereby forcing the data to be reloaded from the volume
database servers.

If you are not using dynroot on UNIX or freelance on Windows, if the
file servers are all down or if all of the copies of the 'root.afs'
volume are offline when the client starts, the client will be unable to
mount the volume.  In the case of the Windows clients they will stop
with a panic condition that is logged to %WinDir%\temp\afsd_init.log

If you file a bug report to openafs-bugs@openafs.org with a stack trace
for the segfault on Linux someone can attempt to fix that.   My guess is
that it is failing because the volume list is empty or some boundary
condition like that.

I have no idea how/why "fs checkvolumes" segfaulting would be a
requirement for subsequent access.

Jeffrey Altman



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