[wplug] disk:ram ratios
jo2y at midnightlinux.com
Fri Nov 16 12:01:39 EST 2001
Does anyone know of a website where they talk about good disk to ram
ratios? I have a file server that is almost constantly at a load of 6-9.
My guess is the machine doesn't have enough ram for disk buffers. Based
on the load and what processes are running (mostly nfs) I think there are
5 or more processes trying to read disk at any one time. If I understand
it correctly, the kernel and disk will read ahead and preload data that
will most likely be asked for next. My theory is that one process does
its read and creates a cache, the next 5 do the same thing and the cache
of the first process gets flushed before it does a read again. In effect
cancelling any buffering effects. So I'm looking for any sites that have
tested this type of thing?
The simple answer would be to just throw as much ram as I can in, but
businesses usually want you to justify the need before they spend money on
If it matters, the machine has 1 gig of RAM and 740gig of disk.
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