On Thu, Dec 02, 2004 at 10:55:57AM +0900 or thereabouts, Georgi Georgiev wrote:
> > all 5 servers in the rsync.gentoo.org rotation are currently running
> > rsync out of ram. i think i can safely say they wouldn't be nearly as
> > fast as they are, running off a hard disk.
> 
> Do you have some real numbers? I am not trying to doubt you too much. I
> am genuinely curious how big the speedup is and if it is worth the
> effort. All I wanted to point in my post is that the speedup is probably
> not that great, but I'd really like to see benchmark numbers if someone
> went to the trouble of doing it.

I can't give real comparison numbers, but I can say that we did see
dramatic improvements when moving from an IDE drive to a ram drive on the
servers in the rsync.g.o rotation.  It's a bit hazy, but I seem to recall
getting killed with much more than 20 or so simultaneous connections on an
IDE-based rsync.g.o server and no more than 30-40 with a SCSI-based one.
With the ram-based servers, we've never seen a ceiling.  Most of our
servers are serving up ~30 simultaneous connections and ~6Mbps on average
and their loads never spike much beyond .4 or so.  

Out of the 5 servers we have in the rotation, we could probably make do
with 2 of them.  The rest are mainly there for spikes during releases and
redundancy in case of failure.

--kurt