Guy [off-list ref] wrote:

I agree, but for a different reason.  Your reason is new to me.
I don't want a down system due to a single disk failure.
Loosing the swap disk would kill the system.

Maybe this is Peter's cause of frequent corruption?

I wouldn't have aid there were frequent failures!  There are relatively
frequent disk errors, at the rate of probably 10 bits per hundred
machines per week. I do not think that is very frequent.

Peter