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Re: Some insight into the number of instances Nova needs to spin up...
Agree the scale limits will increase over time. I'm thinking more about
what the near term (cactus or cactus+1) limits should be.
The model we have been using is a single nova deployment per metro area
(called a region). That metro area could be comprised of multiple Dcs and
failure isolation domains (Amazon calls these availablity zones) within
those Dcs. I recognize that we've been trying to have a flexible model
here and not dictate a specific deployment architecture, but I also think
there are some advantages in not trying to be everything to everyone.
Maybe we should come up with several common deployment scenarios at
different scale, standardize nomenclature, and try to work towards those??
On 12/30/10 12:38 PM, "Bret Piatt" <bret@xxxxxxxxxxxxx> wrote:
>These numbers seem very large today but a decade from now they won't at
>We don't need to design everything for the requirements in 2020 but we
>should have some view on where things are going. More swag
>60,000,000 servers worldwide (I'm assuming this doesn't grow super quickly
>as instead of more, we're making more powerful with additional cores/RAM
>50% of those servers are in "cloud" so 30,000,000
>I'll call a "major cloud player" somebody with 10% market share, so
>For geographic spread I'll assume 10-15 facilities so 200,000-300,000
>servers per facility
>Each facility may be broken up into zones so the question is at what point
>do we make the cross-over from intra-cloud to inter-cloud? If it is at
>zone level we're looking at 20-50k servers per zone with increasing VM
>density so 50-100 VMs per server for a total of 1 million to 5 million
>At each point in the architecture where the cost model changes for
>traffic we need to have a logical construct in place. Potentially
>zone->facility->region->world is enough granularity, we may need
>zone->facility->metro area->region->world. Where we switch from
>(singular management domain) to inter-cloud (connected through a cloud
>directory service with federation) needs to take into account the overhead
>for brokering the additional complexity of inter-cloud communication
>the overhead of a larger singular management domain.
>Twitter: @bpiatt / Mobile 210-867-9338
>Open Source Cloud Infrastructure: http://www.openstack.org
>Of Erik Carlin
>Sent: Thursday, December 30, 2010 12:15 PM
>To: Rick Clark
>Subject: Re: [Openstack] Some insight into the number of instances Nova
>needs to spin up...
>I suggest we consider the limits of a single nova deployment, not across
>regions. To Pete's point, at a certain scale, people will break into
>parallel, independent nova deployments. A single, global, deployment
>becomes untenable at scale.
>I agree with Pete that 1M hosts (and 45M Vms) is a bit out of whack for a
>single nova deployment. As a frame of reference, here are a couple of
>that estimate total server count by the big boys:
>Google is the largest and they are estimated to run ~1M+ servers.
>Microsoft is ~500K+. Facebook is around 60K. This link
>ers-in-the-world/) is a few years old and puts the total worldwide server
>count at 44M.
>I submit that setting the nova limit to match Google's total server count
>and 1/44th of the total worldwide server count is overkill.
>The limits I suggest below are not per AZ, but per nova deployment (there
>could be multiple AZs inside of a deployment). I think we may need to
>clarify nomenclature (although it may just be me since I haven't been too
>engaged in these discussions to date). I know at the last design summit
>was decided to call everything a "zone".
>On 12/30/10 11:42 AM, "Rick Clark" <rick@xxxxxxxxxxxxx> wrote:
>>Actually it was 1M hosts and Ivthink 45 million vms. It was meant to
>>be across all regions. Jason Seats set the number arbitrarily, but it
>>is a good target to not let us forget about scaling while we design.
>>I think eventually all loads will be more ephemeral. So, I think I
>>agree with your numbers, if you are talking about a single availability
>>On 12/30/2010 11:25 AM, Erik Carlin wrote:
>>> 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 link.
>>> 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
>>>> 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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