[OpenAFS] Very large caches

[chas williams]

In message <3C038F31.8030807@est.ibm.com>,Paul Blackburn writes:
>I am curious: have you tried using RAM cache?
>In my experience with Transarc AFS on AIX, RAM cache is very fast.

my general opinion about ram cache is negative.  since ram is usually
a fairly limited resource, people make their ram caches quite small
which leads to poor performance. 

as pointed out earlier though using a ram disk might be a better
idea.  solaris' memory filesystem is especially nice since it shares
with the swap space when memory is short.

i have run a couple 1G caches.  even with older afs releases it was
possible as long as you were putting about 1M in each disk cache entry.
our current general purpose machine uses a 1G openafs cache and i
havent seen any problems and it does get used:

% fs getcacheparms
AFS using 895985 of the cache's available 1048576 1K byte blocks.

i suppose it could stand to be bigger.