Xen, KVM or OpenVZ for private server?

smooch1502

Hello,

I've purchased a dedicated server with 8GB RAM, Intel Celeron G530 CPU and will be using virtualization/container technologies on it.

I've had experience with OpenVZ and management via vzctl and am quite happy with it. However since i will be running some java programs (minecraft server, cloudfoundry) etc OpenVZ has, in the past been quite annoying with its java memory usage.

What would you suggest i use for Virtualization? I personally would prefer Xen PV or KVM, but OpenVZ might be fine (and faster) for this.

Please note i can't afford to purchase any commercial VZ,Xen or KVM panel (SolusVM, VePortal). I've looked at HyperVM but it doesn't say it supports CentOS 6.

My question is, if you were in my situation. Would you use: Xen, KVM? or container based OpenVZ?

Also, if anyone can suggest a way of managing Xen or KVM servers (preferably a web interface? that is also free) please do so.

24khost

Openvz with vzwap would be alright.

but your best be is xen.

smooch1502

I personally do want to use Xen PV (Not HVM, so probably not KVM) but i've been trying to get this working on a local vmware vm (with VT-X enabled) on CentOS 6.3 x86_64 but i've been getting libvirt compilation errors (followed guide: http://www.howtoforge.com/virtualization-with-xen-on-centos-6.3-x86_64-paravirtualization-and-hardware-virtualization) (rpmbuild -bb libvirt.spec).

OpenVZ with VSwap looks great, but i'm still not sure if this'll work out, (one vps will need to run CloudFoundry)?

24khost

The openvz with vswap should work just find for java. I have see multiple people run it now.

smooch1502

Thanks @24khost, would like to hear other peoples opinions, suggestions too though.

jhadley

Sounds like OpenVZ will be easiest for you as you're not using a panel and you know how it works already.

dmmcintyre3

OpenVZ works fine for java. Just give the container lots of privvmpages.

benc555

I think Xen would be your best choice.

wdq

I run Citrix XenServer on all of my dedicated servers. It might not be the best option if you're planning to sell VPS's off of the server (since you can't oversell RAM/storage with XenServer), but otherwise XenServer is great.

BronzeByte

Proxmox is the (open source) way to go, has KVM and OpenVZ in a single kernel. Need something easy to manage but still quite professional or just want Xen? Go with XenCenter Is it non-commercial and can you be bothered? Go with VMware ESXi

Maounique

I also say proxmox is good, for Xen use XCP (both PV and HVM).

M

rchurch

Are Celerons VT enabled? I thought it was only I series and Xeons are.

Maounique

Yeah, I checked and that one is. Celerons today are not what they used to be. It always reminded me of http://en.wikipedia.org/wiki/Coelenterata M

jarland

Although it's pretty much been said, I'll weigh in as I have a dedicated that I run proxmox on for my own usage.

OpenVZ is going to get the most out of your hardware. It performs great, and you can stretch more out of the system. It's not going to be a huge difference to where you're going to see a true virtualization perform significantly better or worse. It's just a little bit more efficient in my experience.

Maounique

Proxmox offers ease of use and larger choice while pure OVZ offers speed. I have a proxmox colo too for my own usage, I would say it is taxing the old dual xeons at about 10% at least. Also, for a secret project, I am working with one on the Prometeus Atoms, it does work, I would say better than expected, but, of course, only for OVZ. However, OVZ under Proxmox is still very snappy. M

rchurch

I have just checked ark.intel.com and it seems that VT-x is standard on all of Intel's latest offerings, except perhaps Atoms. I was looking towards AMDs as it is standard across the line. I will consider a cheap Celeron or Pentium for my next PC. I hope the boards are too.

PS. How does VT-d help? It appears to be available on only i5s and above

craigb

@rchurch vt-d means a VM can be assigned real devices thus improving performance (no emulation needed). This also improves security - security weaknesses exploited in (for example) network cards only impact the VM they are attached to (without vt-d, the underlying host and thus all VMs are pwned)? More from Intel here: http://software.intel.com/en-us/articles/intel-virtualization-technology-for-directed-io-vt-d-enhancing-intel-platforms-for-efficient-virtualization-of-io-devices/

KuJoe

For our internal servers we switched from Xen to KVM then finally to OpenVZ. OpenVZ just performs better and is easier to manage in our experience.

gubbyte

I'm not too knowledgeable in virtualization, but from what I hear from a lot of people OpenVZ has greater performance over other choices. I use it myself most of the time and I don't really have any issues with it apart from the lack of ability to modify the kernel.

tinyray

for those interested,

"A Synthetical Performance Evaluation of OpenVZ, Xen and KVM," IEEE Int'l computing conference, 2010..., http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5708625

Through measuring and analyzing OpenVZ, Xen and KVM with SPEC CPU2006, LINPACK, Kernel compiling, RAMSPEED, LMbench, IOzone, Bonnie++, NetIO, WebBench, SysBench and SPEC JBB2005, we found that OpenVZ has the best performance and Xen follows OpenVZ with a slight degradation in most experiments, while KVM has apparently lower performance than OpenVZ and Xen. Furthermore, this indicates that operating system-level virtualization and para-virtualization have some apparent advantage on data-intensive applications such as disk I/O, net I/O, web server, database server and Java server. However,....

Maounique

Well, OVZ is not really virtualization, just a slicing of a bigger machine with some kernel modules to mimic some aspects of a real virtual machine, so, not a surprise there. However, .32 kernels cannot take so much beating like the .18 ones and are crashing much more frequently under load, especially if there are many containers on the node. No wonder some providers still stick to .18 kernels even tho the .32 rewrite is offering more options and mimics a VM better in many aspects. Regarding Xen and KVM, if we talk about Xen-PV, yeah, that is consistent with the theory, however, Xen-HVM does not perform better compared with KVM on VirtIO drivers in my view, they are about the same. M

KuJoe

@Maounique said: Xen-HVM does not perform better compared with KVM on VirtIO drivers in my view, they are about the same.

Xen HVM and KVM are pretty much identical in performance. Xen HVM will outperform KVM by a slight different in some tests while KVM will outperform KVM by a slight different in other tests but in all performance benchmarks performed you'll see they are , for all intents and purposes, equal.

marcm

@KuJoe How does KVM, when running virtio on the guest and deadline scheduler on the host compare to XenPV in your opinion/experience?

smooch1502

So at first i tried OpenVZ, but java didn't run well (even with vswap). Xen isn't really supported on RHEL/CentOS 6 anymore (officially anyway), so i decided to reformat and go with KVM + LVM partitioning.

Besides a small performance hit, i'm glad i chose KVM (HVM).

marcm

@smooch1502 How is the I/O speed and responsiveness with KVM?

hostdog

What about Cloudmin GPL for KVM ?

smooch1502

@marcm

Not that good really: [root@vm11 ~]# dd bs=1M count=128 if=/dev/zero of=test conv=fdatasync 128+0 records in 128+0 records out 134217728 bytes (134 MB) copied, 1.78848 s, 75.0 MB/s

Mind you, i don't run much.. so its fine for me

PS: I am running a minecraft server on the same VM as i did this test

marcm

@smooch1502 That's perfectly fine. If I may give you some advice from my own experience: set elevator=deadline in your bootloader (kernel line) and the guests to elevator=noop and don't use caching on the guests. I/O should be very consistent with these settings :)

smooch1502

@marcm Too bad the CPU aint that great, with the RAM + HDD here, could've sold some LEBs

marcm

@smooch1502 you still can, but I wouldn't have on my personal server anyone who I don't know - so I guess it would be OK for friends, family, etc. - just my opinion :)

The settings that I've show you are well tested and work great for me on all of our nodes.

smooch1502

@marcm So you think the CPU is fairly good for LEBs?