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

Alena Manova nymano@seznam.cz
Mon, 08 Feb 2010 03:03:08 +0100 (CET)


> ------------ Původní zpráva ------------
> Od: Andrew Deason <adeason@sinenomine.net>
> Předmět: Re: [OpenAFS] Re: [OpenAFS] cache manager locked under h=
eavy load?
> Datum: 08.2.2010 02:09:49
> ----------------------------------------
> On Mon, 08 Feb 2010 00:01:03 +0100 (CET)
> Alena Manova <nymano@seznam.cz> wrote:
> 
> > I am running one fileserver process. should I run more? how to get
> > the optimal number?
> [...]
> > Instance fs, (type is fs) currently running normally.
> >     Auxiliary status is: file server running.
> >     Process last started at Sun Feb  7 04:00:05 2010 (2 proc starts=
)
> >     Command 1 is '/usr/afs/bin/fileserver'
> >     Command 2 is '/usr/afs/bin/volserver'
> >     Command 3 is '/usr/afs/bin/salvager'
> 
> The number of threads you're running with is usually given by the -p
> option to the fileserver. You are running with the default, which I
> think is around 9. Try adding the argument "-p 128" (no quotes) to th=
e
> parameters passed to the fileserver, and see if it affects your probl=
em
> at all.
> 

ok, thanks.

I changed the fileserver to be started with the option -L which means "large" and implies -p 128.

however it didn't help solve my cache manager issue.

I also followed the vCache performance analysis described by Jason but regardless the -stats parameter (even tried with value 1000000) I can't get better hits/misses ratio than about 50% (which is much worse than recommended 1%). how about the 'dynamic-vcaches' feature? it is enabled by default so is the -stats parameter still relevant?

I tried to use the -fakestat-all parameter and it seems it can improve the ratio to 4%. but the issue persists (with same scale).

currently I am running the cache manager with -dynroot -fakestat-all -volumes 256 -daemons 6 -stats 300000 and the fileserver with 128 LWPs. but the issue is still there:

# cmdebug localhost
Lock afs_xvcache status: (writer_waitingupgrade_waiting, upgrade_locked(pid:14367 at:5), 1 read_locks(pid:15308), 288 waiters)

could the memcache help? or what else should I focus on?

thanks for whatever idea, Nick.

> -- 
> Andrew Deason
> adeason@sinenomine.net
> 
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