openstack team mailing list archive

[Blair Bethwaite <blair.bethwaite@xxxxxxxxx>]

On 17 January 2013 09:48, Sean Bigdatafun <sean.bigdatafun@xxxxxxxxx> wrote:

> IMO, it's always a tradeoff. I am just very curious how Amazon configures
> its EC2 hardware.
>

Good luck getting that information! You might be able to make some guesses
from benchmark info though, there is plenty around. This post from Scalyr
takes a great all round look at EC2 IO performance, and it's pretty recent
data: http://blog.scalyr.com/2012/10/16/a-systematic-look-at-ec2-io/ .

Personally, I would guess that for ephemeral drives they use either no RAID
at all or RAID10, probably none though, especially as they don't advertise
any reliability for these drives. The issue of rebuild performance in
parity-based RAID configs and the effect it would have on guest performance
would be a significant consideration. Having said that, it's difficult to
find reports of ephemeral drive failures, and Amazon don't quote any
failure rates themselves.

-- 
Cheers,
~Blairo