█HostPair LLC - Providing Reliable Web Hosting - Since 2009 | Authorized cPanel Partner
█ Shared Hosting | Reseller Hosting | Premium Xen VPS | Windows VPS | Dedicated Server
█ Fast Support | 99.9% Uptime | 30 days Moneyback Guarantee!
█ WHMCS Integration Service - Get your site integrated today!
KVM = full isolation, install from ISO
OpenVZ = not real isolation, install from SolusVM image
KVM is harder.
OpenVZ is easier.
OpenVZ has UBC and vswap methods.
In most all cases, UBC sucks. It's an ancient method of calculating RAM usage.
On UBC a "1GB" VPS is more like 384MB in reality.
So to get 1GB of usable RAM, you need "3GB" available..
This is a question that gets asked a lot, I suggest Googling, 'OpenVZ vs KVM' for some offsite articles and detailed information.
OpenVZ is easier, and often oversold. Some providers manage this better than others, however some providers use OpenVZ to sell 300GB of RAM on a machine with 32GB -actual- RAM. (Yes, this has happened).
OpenVZ isn't as secure as KVM. If someone has access to the VPS node, they can easily enter your VPS by using the vzctl enter CTID command (where 'CTID' is your container ID). Shouldn't be an issue from a trustworthy provider, but worth noting.
OpenVZ, assuming not oversold to death, can be slightly faster than KVM. Will you feel the difference? Maybe, but probably not. It's 'lighter' and doesn't require as much hostnode resources.
KVM is more tamper proof, and more like managing a 'real' server.
With KVM, you can utilize full disk encryption, which is a plus for those seeking an added level of security.
With KVM you can use SELinux, on OpenVZ you can not. (Unless this has changed)
KVM is generally more 'premium' than OpenVZ and slightly more expensive due to it not being oversold, or as oversold as OpenVZ. This means you should have a more stable service, without being impacted by your neighbors as much as you would with OpenVZ.
I prefer KVM when it's an option, as I like to deploy production sites inside a KVM VPS. OpenVZ is fine if you just need something cheap, but I'm starting to lean more towards KVM every day. It's a bit more of a hassle to get setup, but assuming you're going to set it up once and be done it's not too bad in that regard.
vpsBoard - An active resource for all things Virtual Private Servers. Tutorials, Guides, Offers and more!
Come join the conversation! 90,000 posts and growing daily! The fastest growing hosting forum around!