[OpenAFS] Re: [OpenAFS] cache manager locked under heavy load?

Alena Manova nymano@seznam.cz
Sun, 07 Feb 2010 00:01:39 +0100 (CET)

Thanks Simon and Jason,

thank you for the clues!

we are running openafs 1.4.11 on centos 5.4 using the official openafs rpm packages.

I tried running the afsd with -dynroot -fakestat -stat 200000 and still have the issue. if I route the traffic (about 500 requests) to that server, it gets locked.

how about the -daemons parameter? could that be relevant?

I guess the xstat_cm_test is not part of the RPM packages.

thank you, Nick.

> ------------ Původní zpráva ------------
> Od: Simon Wilkinson <sxw@inf.ed.ac.uk>
> Předmět: Re: [OpenAFS] cache manager locked under heavy load?
> Datum: 06.2.2010 22:37:37
> ----------------------------------------
> On 6 Feb 2010, at 21:54, Jason Edgecombe wrote:
> > I'm not familiar with the error, but the fact that "vcache" is in t=
he message
> suggests that you vnode/stat cache is not big enough.
> The lock that message refers to is in GetVCache. This suggests that y=
> thrashing the vcache - as Jason suggests I'd take a careful look at y=
our cache
> statistics.
> I do have some longer term plans for ways of decreasing the contentio=
n here.
> Apache really likes the stat() command, and if we could find ways of =
> the locking necessary to return results to stat(), web serving from A=
FS could be
> substantially faster.
> On 6 Feb 2010, at 21:43, Russ Allbery wrote:
> > We used to see this and then it went away with the current client c=
> > manager.  What version of OpenAFS are you using on your clients?
> I suspect that the work that Derrick did on dynamic vcaches will help=
 with this
> particular case, as it should move cache flushes away from the kernel=
> that's actually doing the access.
> Cheers,
> Simon._______________________________________________
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