Swap Disk for Sun 3/50

[Jeff Weber]

munnari!chook.ua.oz.au!jeremy at uunet.uu.net (Jeremy Webber) writes:
>Conclusions:
>  Sun shoeboxes aren't as fast as an Ethernet.
>  If you are short of memory, more memory is MUCH better than local disks.  It
>    is also much cheaper.

I agree with your conclusions but I think there's more to it......

A. We found that 3/50's were helped more than 3/60's for our large
text&graphics pagination jobs.  No explanation was found after minimal search.

B.  A Client Local Disk (CLD) won't impact performance much if the CLD's
disk is slow.  You want it be as close to memory speed as possible.  Thus
ours is 16ms access time and uses embedded SCSI to reduce propagation
delays.

C.  A CLD won't impact performance much if the fileserver and net are
pretty lightly loaded.  It shows mucho bettero performance when the server
is on its knees.

D.  A CLD did allow us to move some of the server's swap space to /usr
space and we could also put more clients on a net with acceptable
performance.

E.  At <$1300 a 91MB CLD WAS cheaper than a single 4MB memory upgrade.
With our swap space on the fileserver at 25MB, a 75MB swap space on a fast
CLD was nice.  (Our paginated documents will run in the 100's of MB).

F.  For us, 8MB was enough for nice "interactive" performance.  But
"dedicated wait" or "batch performance" was helped by getting away from
the usual Sun disk I/O bottle neck.  Now we can have multiple users
running multiple paginations without locking each other out.

G.  CLD's are most useful in a large network with heavily loaded clients.
Clients that only do memo's and read the news obviously don't need/use a
CLD.


But that's just one man's opinion.

	Jeff Weber