[Swift-devel] Swift-issues (PBS+NFS Cluster)

[Tim Freeman]

On Tue, 12 May 2009 17:24:04 -0500
Tim Freeman <tfreeman at mcs.anl.gov> wrote:

> On Tue, 12 May 2009 15:59:50 -0500
> Ioan Raicu <iraicu at cs.uchicago.edu> wrote:
> 
> > I see the numbers, but my instinct says that they can't scale EBS 
> > performance linearly with every EC2 instance they can start. Perhaps EBS 
> > is currently underutilized, so much that the EBS servers are relatively 
> > idle. 
> 
> Well, they charge extra money when you use it, presumably using some kind of
> cost-plus model.  If demand (relative to raw instance demand) increases
> noticeably, I'd bet they will then be able to afford to add more EBS capacity
> to keep up. They explicitly advertise it as better than local disk (and AWS
> has an excellent track record of doing what they say).
> 
> You may be right about not scaling with every EC2 instance they can start at
> the moment, but that doesn't really matter when you have 100ks of customers
> and nodes, you just need to look at trends and plan accordingly.

Also, who knows, maybe they start rejecting EBS requests at some point to
maintain the target performance.  I'm not going to spend the money to find
out :-)

Tim