Hello,

I have a very simple question, what are the differences between Xen VPS and OpenVZ. I've heard Xen is better but why?

This has been answered before and doing a quick search on google will give you some good comparisons. But I'll try sum it up.

There are 2 kinds of Xen virtualization. Xen-HVM and Xen-PV. Xen-HVM is hardware virtualization, that means it emulates the entire computer. The advantage to this is your VPS acts the exact same a normal computer would and you can run any OS on it. The disadvantage is that it consumes lots of resources since everything is being emulated, so its not as fast as Xen-PV or OpenVZ and is more costly.

Xen-PV is paravirtualization, which is somewhat comparable to OpenVZ. Basically it provides a software interface to the hardware it is being run on. The upside to this is that you get better performance and lower overhead on the server. The trade off is that you can only run Operating systems that can communicate with the software interface (which is only Linux, NetBSD, FreeBSD, OpenSolaris, and an old version of Netware AFAIK).

OpenVZ is container-level virtualization, which basically means isolated Operating systems are run on the same hardware with the same kernel. The advantage to this is that you theoretically have the best performance. The trade off is that you are forced to run linux with the same kernel as the server.

The main difference between Xen-PV and OpenVZ is the memory model (and that Xen-PV can run a customized kernel). OpenVZ uses soft memory allocation (all memory an application allocates, including memory that is not currently in use but a program has said they might, is allocated). Xen-PV only counts resident pages (memory that is currently allocated and in use). One problem with OpenVZ's memory model is that ram is not guaranteed to be physical ram, it may actually be swap. But provided it isn't ridiculously oversold this shouldn't be an issue. Xen-PV's ram is guaranteed to be physical memory, but if its oversold, ram will mysteriously seem to be in used.

Xen-PV makes use of swap (when you need more ram than available, it writes the old memory pages to disk). The advantage to swap is that you can give a VPS a decent amount of (slow) memory for cheap. Currently, OpenVZ uses burst memory. When you use up the dedicated memory for your VPS, it allows you to use burst memory. Burst memory is free memory on the server. If no memory is free on the host node, you can't use burst, but on a properly configured host node and provided its not too oversold, this should never happen.

The new version of OpenVZ (which isn't on too many production servers yet), uses vSwap (Virtual Swap) and comes with an improved memory model that uses the kernel's management of buffers and caches. vSwap is basically artificially slowed burst to mimic swap. It's kind of silly imo, but it will help in improperly oversold nodes that OpenVZ has a bad name for.

So, basically one isn't really better than the other. It depends on your need.

I want to host a minecraft server, OpenVZ is better for me?

I need at least 512 Mb ram and 10-15 GB Hdd, i don't need windows server, a linux server is good.

Can you recommend me something cheap for my needings?


Or what vps is good for my needings, VPS 7 ?

i think VPS 3 or 7 is good for you

(12-02-2011 07:23 PM)gabridobre Wrote:  I want to host a minecraft server, OpenVZ is better for me?

I need at least 512 Mb ram and 10-15 GB Hdd, i don't need windows server, a linux server is good.

Can you recommend me something cheap for my needings?


Or what vps is good for my needings, VPS 7 ?

yeah vps 7 is great
but you can try vps 11
i'll try vps 11 for minecraft/terraria server later until i can afford it

vps 7 will not be good. use a vps 3 or 4. 7's kill all java processes. good luck getting a vps 11, you have 42 score.

What about KVM? Isn't that the best?

If you want to run a mc server i would recommend Xen-PV which has the best java support. also make sure to use sun java and not the other one.

How does KVM have worse java support than Xen-PV?

(12-02-2011 07:23 PM)gabridobre Wrote:  I want to host a minecraft server, OpenVZ is better for me?

I need at least 512 Mb ram and 10-15 GB Hdd, i don't need windows server, a linux server is good.

Can you recommend me something cheap for my needings?


Or what vps is good for my needings, VPS 7 ?

For java, openVZ is the worst choice since Java like to allocate lots of ram for future use. However, given enough ram OpenVZ will work just fine.

If you are looking to pay for a VPS check out lowendbox for some good deals. Hostigation is well regarded and has some nice prices on kvm VPSs though.