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

> 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.

Looks like something similar to NVRAM cards from UMEM http://www.umem.com/
But I think that UMEM cards are only limited to speed of PCI bus, not SATA
bus and thus can be a bit faster.

On 04.04.07 19:10, Matt Cuttler wrote:
> 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 use tmpfs for /tmp, /var/lock and for /var/run. Debian supports all of
these usages, there were problems with some packages in sarge (which
expected some directories to exist after boot) but iirc, debian developers
are forced to support transient filesystems on /var/run...

> 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.

look at those UMEM cards. Although they are designed to be used for
journalling (I'd use data journalling if I had those cards), they can be
used for swapping I'd say.

I think I better would not use them as real RAM due to slower performance
than real RAM...
Matus UHLAR - fantomas, uhlar@fantomas.sk ; http://www.fantomas.sk/
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