1 CPU = 5 vCPUs is okay?
Virtualized CPUs are overcommitted best when each virtualized guest only has a single VCPU. The Linux scheduler is very efficient with this type of load. KVM should safely support guests with loads under 100% at a ratio of 5 VCPUs Overcommitting single VCPU virtualized guests is not an issue.
So, 1 CPU = 5 vCPUs is okay?
Comments
Doesn't matter how "efficient" it is.
One PMSing benchmark junkie is all you need to break down a node.
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Also
MetalVPS
We don't have anybody like that here!
PMSing = yes
benchmark junkie = yes
PMSing + benchmark junkie = no
MetalVPS
DOI: 10.1109/CLOUD.2012.131
MetalVPS
On page 29 of the cited article:
So, assuming similar use to the private cloud example from the cited article, it looks like 1 CPU = 3 vCPUs might be okay?
Here is maybe a more convenient citation to the article from which the above quote is taken: Biting Off Safely More Than You Can Chew: Predictive Analytics for Resource Over-Commit in IaaS Cloud.
MetalVPS
From the example, 16 pCPU cores = 32 provider vCPUs = 99 client vCPUs.
Which makes, 1 pCPU core = 2 provider vCPUs = 6 client vCPUs.
Interesting, how about RAM ratio?
Well, on NanoKVM/microLXC always gave a VM 1 core, so It wont trip any monitoring or performance issues if someone compiles stuff or uses his core. So a single user cannot impact the node's performance for affecting someone else.
Which is quite nice, so everything works flawless.
Of course you can over commit but you may end up in issues.
Free NAT KVM | Free NAT LXC
It's my poor vocabulary. Sometimes I use the term "CPU" to mean "thread." I should be more clear. Thanks for highlighting my ambiguity. That's very helpful!
MetalVPS
Sounds like pretty safe territory to me under average conditions.
Hate radiates from the source. If you look around and see it everywhere, it's coming from you.
Section VI of the cited paper mentions related research involving memory and says that the analytical approach in the cited paper can be extended to run-time memory allocation.
Swap also needs to be considered.
MetalVPS
It's really interesting to see their recommendations on overcommitting memory. Truth be told the professional crowd are a lot less shy about overcommitting than the hobbyist crowd.
Hate radiates from the source. If you look around and see it everywhere, it's coming from you.
Just to be certain, please let me ask: do you mean "1 core" in the sense of "1 thread" which would be 1 "processing unit" in the output of GNU nproc?
There is a guy who uses a desktop environment with Firefox and VScodium under LXC on one of my Xeon D 1521 servers. For awhile I kept asking him if everything works okay. Eventually he said, "I insist it works okay." So I stopped asking.
LXC doesn't get nearly the love that it deserves!
MetalVPS