[YLUG] Server purchase

[Robert Hulme]

> > I'd been told (possibly incorrectly) that software RAID was a big
> > performance hit.
> That was me. Given that you'll be running a database on it, I'd stick
> with that
> assesment. We've not had good experiences with software raid here for
> anything
> other than lightly loaded machines.
I think its undeniable that hardware RAID is faster than software RAID
given that hardware raid uses true XOR (?) hardware acceleration
devices. This only counts if you get a real (and expensive!) hardware
RAID card though - beware, most of the less expensive cards out there
are 'fake' hardware RAID (http://linux-ata.org/faq-sata-raid.html).

Hardware RAID also has the advantage that it comes with a battery
backed controller so if your power supply (for instance) bursts into
flames you can be sure (well assuming the power supply didnt screw
over the card as it died!) that data that is in the write cache will
still get committed to disk.

Software RAID is reasonably fast though IMO, Google should be able to
show you some benchmarks. I question whether you need hardware RAID in
terms of performance for the kind of setup you want (given that you
only seem to need one disks worth of performance and space). RAID-1
through software would be very fast (the bit that makes software RAID
slow is the RAID-5 XOR calculations). That would provide you with
mirroring across two (or more - but that would be real overkill)
disks.

At the very least you could order the box, put software RAID on it and
benchmark it.

I don't know what kind of databases you'll be running on there but I
suspect that more RAM will massively increase performance far more
than anything you'll get out of having lots of disks in there anyway.
-- 
------------------------------------------------------
"98.5% of DNA is considered to be junk DNA with no known purpose.
Maybe it's XML tags." -- Anon

"Debugging is twice as hard as writing the code in the first place.
Therefore, if you write the code as cleverly as possible, you are, by
definition, not smart enough to debug it." - Kernighan

http://www.robhulme.com/
http://robhu.livejournal.com/