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Virtualizor Memory Overcommit bug
Question for the providers out there using Virtualizor KVM with the memory overcommit feature. Has anybody faced the issue where VM's are preallocating the entire ram amount on boot instead of resizing based on how much is actually being used? Virtualizor support are practically brick walls when it comes to it so I wanted to ask here.
Windows appears to do it instantly on boot and Virtualizor staff have confirmed that is a bug, but they can't fix it as it's a libvirt issue and then there's Linux which appears to do it after time (at least on my node).
Yes I think I have faced it
CentOS 7 right ?
Correct, it's really annoying me. I have 4 VM's running and it's using 21GB of memory lmao.
Yes this is a bug ask Anthony Smith
@AnthonySmith - Care to explain your experience with this and if you came to a resolution at all? I REALLY do not want to reinstall to CentOS 6 as my DC charges a million bucks for RH.
why no IPMI? a huge hassle without it remotely. If the DC is in Dallas I'd hop over and do it for free.
Well that's a funny story now you mention it, TLDR: I waited 3 months due to DC incompetence of plugging into the wrong serial connection to even get CentOS 7 installed and I am absolutely certain something will break this time around and I'll have to ship the server back to me and then back to them cos it'll be cheaper.
Unfortunately, it's in the Netherlands I am unsure if this bug happens on CentOS 6 or not, there isn't really any documentation about it anywhere. Hopefully Anthony can shed some light on it.
I can't say I have seen it myself, perhaps post a ticket number and give a more detailed description, happy to work through it and see what is going on.
Does the guest actually see all the ram?
If it is what I suspect it is I can probably write you a quick script to fix it while a permanent solution is found, solusvm had a similar issue with setting some max buffers to low so I guess I can adapt that to work for this.
Also, I have no nodes using the overcommits so maybe that's why I am not seeing it but that said I would not use anything in virtualizor to do it anyway, it is far best managing that from the os directly.
So, virtualizor support is useless?
Virtualizor staff have confirmed that is a bug, but they can't fix it as it's a libvirt issue
You read well.
And how did you feel to back on actual topic?
I'm working at the moment so I wouldn't be able to give you all that information right now but it's the latest CentOS 7 installation and the latest Virtualizor installation aswell. The customer itself inside the node doesn't show that it's using all the ram, it shows what they are actually using.
If you want to take a look I wouldn't mind giving you access to have a gander, it's cool if you don't though. I've been speaking directly with Chirag @ Softaculous about it and he's confirmed the Windows side of it but not the Linux side. It doesn't appear to do it immediately on boot like Windows does. It does it after time of it being booted.
Thanks for taking an interest my man.
oh you know Ant @AnthonySmith takes an interest, did you see how much interest he had in solusvm lol
Well, let me know when you can present your own troubleshooting info I will take a look from there.
Also be aware that there are big differences in libvirt between centos 7.3.xxxx and 7.4
Kernel Version: 3.10.0-693.5.2.el7.x86_64
Linux version: CentOS Linux release 7.4.1708 (Core)
Libvirt version: 3.2.0