[OpenAFS] OpenAFS 1.6.5 Linux client cache sizes

Derek Atkins warlord@MIT.EDU
Thu, 08 Jan 2015 09:49:25 -0500


Volkmar Glauche <volkmar.glauche@uniklinik-freiburg.de> writes:

> Dear all,
> we are running OpenAFS clients with up to 1TB space available for
> cache partitions. These are multiuser cluster nodes where cache space
> should be as large as possible. Until now, there was (inadvertently) a
> limit of ~200GB set to the cache size by restrictive afsd options.
> I now removed most of these options, my current command line for afsd
> looks like
> /usr/bin/afsd -chunksize 30 -fakestat -blocks <SPACE_ON_DEVICE>
> Now it takes a very long time (~hours) to start up afsd, in some cases
> the afs cache scan even fails with a kernel panic. Is there any way to
> make efficient use of ~1TB cache partitions?

How much RAM do these systems have?  Each cache item requires some
amount of ram to keep track of it.  There is a balancing act of cache
partition size to ram usage.  Going from 200GB -> 1TB of cache will
require >5x the RAM usage to maintain the cache.

> Volkmar


       Derek Atkins, SB '93 MIT EE, SM '95 MIT Media Laboratory
       Member, MIT Student Information Processing Board  (SIPB)
       URL: http://web.mit.edu/warlord/    PP-ASEL-IA     N1NWH
       warlord@MIT.EDU                        PGP key available