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Re: [MirageOS-devel] Memory requirements for a typical Mirage OS VM

On 24/02/2014 10:48, George Dunlap wrote:
On 02/23/2014 03:50 PM, Anil Madhavapeddy wrote:
On 23 Feb 2014, at 12:57, Lars Kurth <lars.kurth@xxxxxxx> wrote:

On 22/02/2014 22:29, Richard Mortier wrote:
On 22 Feb 2014, at 22:13, Julian Chesterfield <julian.chesterfield@xxxxxxxxx> wrote:

So hosting the website image will require more ram than a minimal image.
yes; hence my question about what "typical" means :)
The background for the question was whether the event channel improvements in Xen 4.4 (and thus the capability to run a lot of smaller VMs on one host) will benefit Mirage OS and others. That argement hinges on Mirage OS (and similar) having significantly smaller memory footprints that your traditional VM.

I guess "typical" means "memory requirements for the type of workloads Mirage OS is aiming to target
They definitely will have a big positive impact. Our overall goal is to get an equivalent number of MirageOS VMs running as you can get distinct processes running on a single Unix host. If most are idle (e.g. just brief amount of traffic) and we are using modern 64-core machines, then we've estimated that we able to get to 10000 VMs without too many problems, with these problems rearing their head:

Lars, I think you're missing part of the question: Matt Wilson's question (re our press release) was whether event channel scalability will have a benefit to MirageOS, OSV, and others *in public clouds*. At least a few years ago, the assumption was that most public clouds would be using massive amounts of rather inexpensive machines; maybe 8 cores at the most.

So yes, for 64+core machines, event channels will obviously be a scalability limit. But is it really even useful to try to run >1000 actual servers on an 8-core box? Even if you have enough memory for them all, do yo have enough CPU?
I suppose I did miss this. Too much mult-tasking )-: And https://www.linux.com/news/enterprise/cloud-computing/751156-are-cloud-operating-systems-the-next-big-thing- under "Remaining challenges" actually look at issues.

Of course the default size of physical servers in the cloud may have changed; maybe public clouds now have 64-core boxes. But given the person who asked the question, I'm inclined to think it hasn't changed much.

Maybe a the more correct thing would be to say that we are building the foundations that will enable Cloud OS use-cases in future incarnations of public clouds


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