Hi Lyle,
It is interesting that you believe "A memory-based cache does not
usually improve performance". Having used both disk and memory based
caches. My experience is that a RAM cache is considerably faster.
Also, in terms of clock cycles, RAM access is probably of the order
of 30-50 cycles but disk access is more like 500,000+ cycles.
Please can you help me understand why a memory base cache would
not perform well?
BTW, we find that for most of our workstations, a 64MB disk cache
provides good performance. Larger disk caches get slower.
--
cheers
paul http://acm.org/~mpb
Lyle wrote:
>The time required to reclaim (recycle) space in the cache increases
>linearly with the number of chunks. A memory-based cache does not
>usually improve performance; it was implemented solely to support
>diskless workstations.
>
>I'm pretty sure that you can "spiff up response" through appropriate
>tuning, but acheiving optimal performance requires some study and
>analysis.
>
>Are you presently tuning any of the afsd switches? Using "rc.large",
>for instance? If not, then I can definitely guarantee some
>improvements. If so, try also adding "-files 2800".
>
>Do your users log out and log in frequently? If so, consider adding
>"unlog" to their logout procedure.
