Will prestoserve help a client

[Frank Wortner]

In article <PCG.91Mar17180404 at aberdb.test.aber.ac.uk>,
pcg at test.aber.ac.uk (Piercarlo Antonio Grandi) writes:
 
> Rethorical question: how many megabytes of extra disk buffer cache on
> the client or server can you buy for the cost of one NFS accelerator?

Buffer cache really doesn't fulfill the same function.  Unless the cache
is nonvolatile,
a system crash will destroy any data that hasn't been flushed to disk. 
Since PrestoServe
commits transactions to "stable storage," it can safely buffer
transactions that normally
can only use a buffer cache as a "write-through" cache, if they can use
it at all.

The other assumption you're making is that this is all done by expensive
memory.  If that
were the case, it should be possible to simply increase the size of the
buffer cache and
watch disk performance go through the roof.  If that was all, then
someone would have
surely discovered this by now.  NFS accellerators also use sophisticated
software to manage
and control the cache.  The cache itself is only half the story.  The
hardware/software
combination is what makes the product.


						Frank