i-ram vs. tmpfs (was: Re: Mail clustering)

[Matt Cuttler <mcuttler@bnl.gov>]

Craig Sanders wrote:
> do a google search for "gigabyte i-ram".  
>
> it's a PCI card which you can stick up to 4GB of RAM into, and which you
> can plug into an IDE interface. it looks to the system just like an IDE
> disk. it has a 10-16 hour battery backup built-in, trickle-charged while
> the system is up and running.
>
> currently about $200 AUD with no RAM.
>   

I have frequently mounted various /var directories as tmpfs for mail
serving / content scanning, and other non-mail-related things (such as
Ganglia RRD files etc.). Of course, you have to be aware of how much
free physical RAM is available on your box, or else you're back to using
the disk (swap).

I'd say as a _very general_ statement that if you're doing heavy content
scanning on your mail server (or the box that sits {in front of, behind
your} mail server), you are more likely to be CPU bound than memory bound.

OTOH, it'd be interesting to see how this i-ram card would perform as
swap space -- but then again (from the little I've read) it's a SATA-1
interface; I'm wondering if using a faster fibre channel or SCSI disk
would yield similar real-world performance.

-Matt Cuttler