On Jan 10,  3:35pm, David Brownlee wrote:
> Subject: Re: Any HD size limitations on boot disk?
> [ ...]

Good FAQ entry, but some comments:

>           + For mfs(8) filesystems - classically mounted on /tmp in order
>             to speed up any programs using /tmp, by adding the following
>             to the fstab(5) file:
> 		    swap  /tmp  mfs  rw,-ssize 0 0
>             where size is in 512byte blocks. The space required
>             is taken from the swap space as the filesystem is used.

I always wanted opinions on whether the "async" flag should be specified here.
I use it on some of my systems:
     swap /tmp mfs rw,async,-s100000  0 0

Theoretically, "async" should be faster. I didn't notice a performance increase
with "async", though, but it didn't hurt either.

>
>           The 'correct' value for swap is dependent on the usage of the
>           system, but a general rule might be the larger of RAM or 32MB.
>           Another good rule is to always try to split swap across as many
>           disk as possible to increase the available swap bandwidth.

IMHO, this is too small a value for swap. mount_mfs will never free pages in
it's lifetime. Once /tmp has been written full, mount_mfs lingers around with
'size' pages allocated, even if you clean /tmp. And since the size of the swap
area is not easily increasable after installation (imagine a notebook without
even the possibility to add a second HD with additional swap), I'd suggest to
increase the swap space size recommendation in the FAQ.

My personal decision on swap space is 2.5*RAM, with mfs limited to half of the
swap space.


Cheers
Lex