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Re: Recommended/Not Recommended Hosts?

From: Josh Livni <josh(at)umbrellaconsulting(dot)com>
To: Josh Berkus <josh(at)agliodbs(dot)com>
Cc: SF Postgres <sfpug(at)postgresql(dot)org>
Subject: Re: Recommended/Not Recommended Hosts?
Date: 2009-12-10 19:30:37
Message-ID: (view raw, whole thread or download thread mbox)
Lists: sfpug
Cool, Thanks for the detailed response.  I've certainly not done a ton of
research comparing different VPS solutions myself,  but I was under the
(quite possible mis-impression) that at EC2 the underlying hardware was not
1:1 related to your performance (eg you get a set amount of cpu throughput,
and if they had older hardware underneath, then you'd just get more of it).
 I also did not realize other users could steal cycles from you like happens
on most other VPS offerings.  I haven't seen that much documentation to base
any of these assumptions on, of course, so it's good to hear your

Some posts, such as,
seem to imply different conclusions (not that he's suggesting EC2 is a good
deal, but for different reasons than cpu stealing), and I'd love to see
similar posts on the topic:  I'd be happy to switch to something else if I
felt I was going to getting a much better deal (I really do like the
integrated EBS/S3/Cloudfront options tho for the type of projects I
generally work on).



On Thu, Dec 10, 2009 at 11:20 AM, Josh Berkus <josh(at)agliodbs(dot)com> wrote:

> Josh,
> > Pure curiosity on my part here ... I use EC2 a bit, tho not as much as
> > the serious users.  A few large and small instances on all the time, and
> > I boot up new ones for shorter periods all the time.   First - I've
> > never had any issue getting my instances fulfilled right away (I always
> > use EAST-C, but perhaps other datacenters are generally more full, or
> > you are trying to boot up many tens of servers at once?).
> Yeah, the two issues I've had are (a) requisitioning high-end instances
> (like 32G/16core instances) and (b) allocating a lot at once.  Sometimes
> instances just "aren't available" and there's no way to find out when
> they will be available.
> > Also, when you say they are slow, do you mean in terms of $/cycle,
> > or you wish you had burst access to other users unused cycles like on
> > some other vps offerings? something else?
> I mean that if you have an 8core/16GB instance, the actual processing
> throughput you get is about 1/6 to 1/4 that of a new HP DL380 machine
> with 8cores and 16GB.  So you really need 4x as many EC2 instances to
> match bare metal.  Partly this is due to CPU-stealing, and partly to
> erratic and lag-prone I/O, and partly to the fact that a lot of machines
> in the EC2 pool are 4 years old.
> > I like the bundle of offerings that AWS provides (EBS, especially), and
> > I've personally had great experience w/them (fwiw I've also had great
> > experience w/slicehost) -- but if I am getting missing out on how
> > they're screwing me, for example by stealing my CPU, I'd definitely love
> > to learn more.
> On EC2, other VMs on the same hardware are permitted to "steal" portions
> of the CPU which are allocated to you.  So at any given time, you may
> have as little as 50% of the CPUs you're being billed for.  And, when
> CPU availability is fluctuating up and down (as it does on EC2), real
> throughput tends to be based on the slowest second rather than peak
> availablity.  Most Linux apps, especially databases, do quite poorly
> with erratic resource availability.
> --Josh

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Subject: Re: Recommended/Not Recommended Hosts?
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