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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: 698156f30912101130y30a5b038x17b783f60be84956@mail.gmail.com (view raw or flat)
Thread:
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
perspective.

Some posts, such as http://journal.uggedal.com/vps-performance-comparison,
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).

Cheers,

 -Josh


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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