Excessive disk cache activity.

[Chuck Lever]

is the arla cache on a file system mounted with the "sync" option?

i've found that when installing arla on Linux, putting the cache
on a file system that is mounted with the "noatime" option, and
without the "sync" option, is very helpful for performance and
eliminates unecessary disk activity.

Magnus Ahltorp wrote:
> 
> > - When I would ls an AFS cell (I used stacken.kth.se cell because Yale
> > does not have an AFS cell yet) I would get a lot of disk activity (the
> > drive did an excessive amount of seeking very rapidly).
> >
> > This is obviously cache-related, but it is not a good sound (too much
> > seeking in a small area of the drive). This seeking activity would
> > continue for almost a minute after each simple ls.
> 
> It could be the precreation of cache nodes, but then it shouldn't just
> happen after each ls, but rather a while after arlad was started. You
> haven't enabled xfs debugging or something?
> 
> > Also, the operations I was doing (just ls'ing the same small directory a
> > few times) should not have required using the on-disk cache at all after
> > the first attempt.
> 
> It should not write something to the cache, but it will certainly read
> from it, since you repeated the ls command.
> 
> > How do I add things to the root directory? (arlad -t seemed to mount the
> > milko server (it was registering GetRoot fetches), but "ls /afs"
> > returned "Not a directory" and I couldn't figure out how one goes about
> > actually placing things in the volume.
> 
> If you have run "volmgr gen-ontop-vol <partition-name> <volume-id>",
> you should have a volume with a top directory. Don't expect too much
> though, milko is not much more than a proof-of-concept, and it will be
> rewritten.
> 
> /Magnus
> map at stacken.kth.se
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