Re: i-ram vs. tmpfs (was: Re: Mail clustering)
On Wed, Apr 04, 2007 at 11:50:00PM +0000, Andy Smith wrote:
> On Wed, Apr 04, 2007 at 07:10:30PM -0400, Matt Cuttler wrote:
> > OTOH, it'd be interesting to see how this i-ram card would perform as
> > swap space
> If you have 4G of RAM to put in an i-RAM then why would you use it
> as swap? If your machine swaps, use the 4G as real RAM!
> I'd say the killer application for i-RAM is something like holding
> external journals of other filesystems.
yep, that and postfix (or other MTA) queues.
disk i/o is the main bottleneck in any mail server. if you can offload
that to fast (but battery-backed!), ram-disk then you have a massive
performance gain on a loaded mail server.
BTW, from what i've heard, there isn't much difference between using
an I-RAM as an external journal and using any reasonably fast disk
drive. i.e. using any external journal device gives you most of the
benefit, after that it's diminishing returns. and a new hard disk is a
lot cheaper than an I-RAM. about $50 AUD for a brand-new 80GB drive,
which is about the smallest drive you can get nowadays.
i.e. spend $50 on a new SATA drive for the external journal device
and get 80-90% of the performance improvement that you would get for
spending $500 on a 4GB I-RAM.
craig sanders <email@example.com>
I figure that if God actually does exist, He's big enough to understand an
honest difference of opinion.
-- Isaac Asimov