Dell and SSD drives

[Adam Nielsen]

> I am looking at our mail servers and trying to get some disk IO
> contentions down. I would like to know if people have used SSD's in a
> Linux environment. I am looking at an SSD over a ramdisk for
> persistence of storage in case of reboots. What I would like to do is
> put in 2 SSD's into a 2950 and have them deal with the malware and
> spam scanning directories as that seems to be the contention points.

When you say "reboots" do you mean unexpected hardware resets, or 
intentional shutdown+restart?  Unexpected hardware resets will almost 
always cause some amount of data loss, but if you want persistence over 
controlled restarts then I agree with the other posts here that putting 
as much RAM in the machine as you can will provide a decent speed 
increase, as Linux will use all the extra RAM for disk caching.  In the 
case of a mail server, messages could arrive and be retrieved by clients 
without ever touching the disk - assuming of course clients check their 
mail before it gets flushed out to disk - the more mail you have passing 
through the machine (and the less RAM), the sooner this will happen.

Persistence over reboots here wouldn't be a problem, as the disk cache 
will get written out before shut down.

Perhaps another alternative is one of those i-RAM type cards, which let 
you attach battery-backed RAM to a SATA port.  I think they'd be in the 
same price range as an SSD, only they're a *lot* faster (apparently the 
SATA port is the bottleneck, so ~300MB/sec read/write.)  I think they'd 
certainly be the fastest option, however I'm not sure whether you can 
get them in decent sizes (maybe 8-16GB?)  The battery would also 
guarantee persistence over reboots and (short) shut downs.

Cheers,
Adam.