Things I should know about OpenVZ
I have decided to go with OpenVZ as my virtulization after trying out KVM and playing with it for few days. Not doing an OpenVZ vs KVM debate here, I am sure there are more advantage to KVM but it's just not for me at this point. Plus it's my own setup and I know I don't really need that much.
So now, my question is what I should I know about OpenVZ ?? What setting you would recommend me??? Since this will be first time me doing visualization myself. I have managed servers, vps etc .. but never really used server to create vps before.
(Like http://www.lowendtalk.com/discussion/37153/openvz-simfs-vs-ploop/) I should probably go with Simfs.
Any other thing to note down like that ^^^?
Just so you know, the server is for my own sites. With the ability to have isolation among my sites and also giving me room to test things out. (And learning as well) i.e. I am not into "hosting business" but I like to try and learn new things.
Seen a few problems with ploop (likely had have external factors), never seen one with simfs. Take that as you will.
Read the vzctl manual top to bottom. Always read vzctl release notes.
Above all else, have fun.
Use proxmox, easy
Don't bother setting up LVM unless you are sure you need it. Just makes things needlessly complicated imho.
Do set up SW RAID 1. HD's are cheap and it's fairly straight forward.
Make your root (no need for separate root and boot partitions) partition big enough to store several kernels and kernel dumps. Also give yourself a nice big swap partition. Again, HD's are big and cheap so give yourself lots of room.
A lot of instructions out there have been copied or handed down through the years from back when HD's weren't that big and are hopelessly outdated.
Well after reading up all the views, reviews and forum I have actually decided to go with Solus. (I personally played with SolusVM and Vrtualizor.com, as they were my top picks)
PS. This topis is more about OpenVZ and less about panel.
Can't go wrong with Solus. Proxmox is ok for development but I wouldn't use it for anything commercial. Especially hosting.
Ohhh .. My server is pretty awesome. It has SSD in HW Raid 1. I have one important blog (high traffic) and few simple sites. So yeah, server is not an issue.
If you do not need to run custom kernel on each guest(VPS) OpenVZ with simfs would be the best choice as OpenVZ has less overhead & simfs is much more stable & time tested as compared to ploop. Regarding control panel, SolusVM & Virtualizor both are good but I have seen that for last year or so virtualizor have become more efficient & offer more features than SolusVM. They also try to implement what their customers want. So I would personally prefer virtualizor but that is just my own opinion.
He said he will not sell, that;s why I suggest Proxmox
Let's not get into "which panel is better" ... I tested both, both are pretty amazing. I am just going with Souls at this time.
So, back to topic .. Which else I should consider / remember / tweak to get the best out of OpenVZ.
(I do need stability and performance. Even though it's for my own stuff, I do have one important site on it which can not go down)
Duly noted. Anything else?
OpenVZ does not support Windows & custom ISO. Containers(VPS) share host node's kernel. It also does not reserve memory & disk space allocated to a particular VPS so you can easily over-allocate resources without any worries if you are unsure about resource usage of each website or project.
Yup... I know that part. I just need Centos/Debian ... So I am all set there.
I am asking for things like "openvz simfs vs ploop" ... I mean, I had no idea how that effects until two days ago...
Any particular settings/config in Solus/OpenVZ to get the most out of my setup?
Nope there are hardly any specific settings in SolusVM which can affect efficiency of your VPS servers.
Not in Solus but a few on OpenVZ. It's mostly idiot proof though.
nf_conntrack is one but only for high traffic. Cannot disable this on the node if you want to do anything with iptables states on the node.
Do we really need Swap space on main node??
I mean if the system has enough RAM (64GB) and is only going to be used for 3/4 VMs, do we really need Swap on main node???
I only have 300GB SSD but have enough RAM for my needs. So trying to remove swap (which is 64GB right now) and add the space back to /vz partition.
Just wondering if there will be any issue...
(or can I just go with 2GB Swap?)
swap is mandatory not optional. however, if there's adequate hardware resources, you can possibly minimize allocation and assign extra space to /vz
You don't need swap, why would it be "mandatory"? You can always add a swap file later if you find that processes are getting killed.
hmm I thought linux OSes require swap to work?
No, it just saves some memory, swap is only helpful when you don't have enough RAM. When you have plenty of RAM, having small swap space can clear up some space for memory for buffers and filesystem caching (rarely used pages would be swapped out to disk), but not really big deal (60 GB cache for 300 GB SSD...).
@Umair You run noobslab right? If you are the same Umair running noobslab, Hooray for your contribution to open source
Need some help here. I have setup OpenVZ using SolusVM. So I created my 1st VPS and ran serverbear benchmark just to see how that will work. The VPS was created with default settings that Solus Suggested. (4CPU Cores, 1000 units etc)
The main node is running E5-16500 CPU (6C/12HT)
Now I was expecting serverbear scores to be 1/3rd of the main node. But those seems be to be just 1/2nd. On main node
Welll this is fine by me. (I mean don't think that is an issue)
All other results seems fine. But one thing is just way off.
On main Node
Is there some setting/tweak that I have not done?? Or the ServerBear benchmark will just not work properly with OpenVZ?? Or I am missing some setting in SolusVM??
I mean, that read write bandwidth is way off ...
Thanks for help.
I tried to run the FIO test directly on VPS but didn't see much of an issue...
@Umair, no need to bump again already.
Have you any I/O Priorities set?
Yes you should create a swap partition. The reason being....why not? HD's are big and cheap. Use them. If you are using SSD I would still create a small swap partition. I have not run into any myself but there are supposedly some things that will freak out if they do not see any swap.
Yes you can create a swap file later on if you are not sure you need it...however, partition is better imho.
I/O Priority is set to 4 (their recommended value) .. Pretty much everything else is on default/recommended settings.
Ermmm ... That was already sorted :P
Anyway, I think there is no need to have (Ram+2GB) swap space (as given in solusvm docs) if you enough RAM on the box. I have set 4GB swap with 10 swappiness on main node. So I am good.
That rule of thumb to make swap the same size as RAM or 2xRAM or whatever comes from back in the days when RAM was expensive and people rarely used more than maybe 2GB-4GB. Now a days I base it on HD size. For 1TB drives I just make it 10GB because it's a nice round number and almost nothing on a 1TB.
Openvz can be oversold as hell.
Thank you peanut gallery for that obligatory post that you guys feel compelled to add to every OpenVZ discussion. Maybe you guys should just create a bot that goes around the web looking for the OVZ keywords and just posts that everywhere it finds them.
huh? Am not talking about peanuts
So can XEN and KVM? Please google before posting