Re: /tmp (as a RAM disk?) in a small root partition

[Russell Coker <russell@coker.com.au>]

>    While thinking about this I was wandering if it would be possible to
>make /tmp a RAM disk like Solaris does. But this would only help if the
>size of the RAM disk would be variable, i. e. if the amount of RAM used for
>this would grow and shrink as files in /tmp are written or deleted.

Run bonnie++ on Linux machines with ReiserFS and Solaris machines with tmpfs.
Make sure that the CPU speeds in MHz are about equal (slightly unfair to the
Linux machines as SPARC potentially does more per MHz - and is certainly
priced accordingly).  Make aure that the hard drives are of comparable size,
IDE for Linux and Ultra-SCSI for Solaris.  Make sure that RAM sizes are
comparable too.

For tests of creating and deleting large numbers of files expect Linux to win.

For tests of character at a time IO expect Solaris to win because SPARC is
good at this.

For tests of bulk IO (with size >= 2* RAM) expect it to be a close thing, it
could go either way.

Tmpfs does not perform so well in my experience.  I don't think that we need
it on Linux.

For any performance-related thing that Solaris has/does I suggest
benchmarking against something comparable in Linux.  Chances are you can get
the same or better performance for much less money.

-- 
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