[comp.sys.hp] Swap Space Configuration

rl23+@andrew.cmu.edu (Robert Griswold Lefferts) (06/11/90)

I am trying to reconfigure a bunch of HP 370's into a cluster, where the
cluster server has two hp7958B disks (152 MB) and one hp7958 disk (130 MB).
Each machine in the cluster has 16 MB of memory, and I'm estimating that I
will need about 160-170 MB of swap space total. (about 40 MB per machine -
that may be a bit over-configured, but we tend to run a lot of heavy
processes.)

So, the heart of the issue is, what is the best way to configure the swap
space on the various disks? Or will it make difference?

The two configurations that I have been considering are:

1) 64 MB on each of the 7958Bs, and 40 MB on the 7958.

2) 20 MB on the 7958 (or a 7958B) and one of the 7958Bs totally allocated
   for swap.

Unfortunately, I don't know enough about the way that the swapping algorithm
works to see if one of these configurations is clearly preferable to another.
I've been told that having two disks to swap onto is clearly preferable to one,
since the algorithm can interleave the information on the disks. But is it
true that 3 disks is better than 2? Also, is there anything gained in having
a disk that is totally allocated to swapping?

Thanks in advance,

Rob Lefferts

rl23@andrew.cmu.edu

campbelr@hpclrec.HP.COM (Bob Campbell) (06/12/90)

You may get several votes on this, but I would suggest splitting the
swap evenly between the two 7958Bs.  They are higher performance
drives than the 7958(A) and it is best to have swap equally split.

Bob Campbell                Some times I wish that I could stop you from 
campbelr@hpda.hp.com        talking, when I hear the silly things you say.
Hewlett Packard                                    - Elvis Costello