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Re: Some insight into the number of instances Nova needs to spin up...


You are right.  The 1M number was VMs not hosts.  At least, that was from
one scale discussion we had within Rackspace.  I'm not sure what the
"official" nova target limits are and I can't find anything on launchpad
that defines it.  If there is something, could someone please send me a

I'm am certain that Google can manage more than 10K physical servers per
DC. Rackspace does this today.

If I combine what I know about EC2 and Cloud Servers, I would set the ROM
scale targets as:

1M VMs
50K hosts

500K transactions/day (create/delete server, list servers, resize server,
etc. - granted, some are more expensive than others)
That works out to ~21K/hr but it won't be evenly distributed.  To allow
for peak, I would say something like 75K/hour or ~21/sec.



On 12/30/10 9:20 AM, "Pete Zaitcev" <zaitcev@xxxxxxxxxx> wrote:

>On Wed, 29 Dec 2010 19:27:09 +0000
>Erik Carlin <erik.carlin@xxxxxxxxxxxxx> wrote:
>> The 1M host limit still seems reasonable to me. []
>In my opinion, such numbers are completely out of whack. Google's Chubby
>article says that the busiest Chubby has 90,000 clients (not hosts!) and
>the biggest datacenter has 10,000 systems. They found such numbers
>pushing the border of unmanageable. Granted they did not use
>virtualization, but we're talking the number of boxes in both cases.
>So to reach 1M hosts in a Nova instance you have to have it manage
>100 datacenters. There are going to be calls for federation of Novas
>long before this number is reached.
>Sustaining a high flap rate is a worthy goal and will have an
>important practical impact. And having realistic sizing ideas is
>going to help it.
>-- Pete

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