[OpenAFS] File server not parallelized on restart?

[Tom Keiser]

On 10/17/07, Derrick Brashear <shadow@gmail.com> wrote:
>
>
> On 10/17/07, Steve Simmons <scs@umich.edu> wrote:
> > We had an AFS hang today (more detail after we complete the post-
> > mortem). It required doing a hard reboot on the server. On reboot, it
> > began salvaging the two partitions in parallel as normal. Wwhen the
> > salvages completed, it started attaching the partitions sequentially.
> > Here are the relevant times and events from the log. This last 4 in
> > the sequence look funny to me:
> >
> > 13:30:40 /vicepa salvage started
> > 13:30:40 /vicepb salvage started
> > 14:23:07 /vicepb salvage completed
> > 14:35:59 /vicepa salvage completed
> > 14:36:01 fs starts attaching /vicepb volumes
> > 14:50:16 fs finishes attaching /vicepb volumes
> > 14:50:16 fs starts attaching /vicepa volumes
> >
> > Should it have started attaching /vicepa volumes as soon as that
> > salvage completed, or am I laboring under a misconception here?
> >

The mode of operation is basically whole-partition-salvager XOR
fileserver+volserver.  In order to guarantee mutually exclusive
access, the bosserver won't start the fileserver and volserver until
the salvager has exited.

> > Advance thanks,
>
> nope, it's serial unless you have 1.5, with -vattachpar set, and will do
> them in reverse in some versions due to a minor bug since fixed.
>

Parallel volume attachment support ships with 1.3.83 and above.
Parallel shutdown requires DAFS.  As Derrick mentioned, -vattachpar
controls parallelization of startup and shutdown in the volume
package.  Unless set explicitly, -vattachpar has a value of 1, thus
providing the classic single threaded behavior by default.  The
single-threaded partition attachment ordering fix was committed in
time for 1.4.4.

Regards,

-Tom