Why do people like KVM better than OpenVZ?

jar

@Mark_R said:
Don't try to put my words in the wrong direction

I didn't, that was you. Read this:

companies that do not switch to newer and improved software to provide their services are either lazy or just wanna reduce their costs ... they just dont care about the user experience

I can't take that out of context, you made yourself very clear. You don't know how to run a business or take care of clients. You also think your personal definitions of "new" and "improved" are universal enough to speak condescendingly of others when your definition of "new" is flawed (because both are new) and "improved" is relative because not everyone needs the same thing.

Also I'm pretty sure virtuozzo is "newer" than QEMU but I'll let you dig wikipedia for that.

Chumbi

KVM makes use of modern CPUs for better virtualization and isolation. In fact, here it's the CPU that does the magic (VT-x/VT-d extensions - http://en.wikipedia.org/wiki/X86_virtualization). That's why you cannot use KVM on old hosts that don't support hardware virtualization.

OpenVZ/Virtuozzo on the other hand is not a virtualization. It doesn't virtualize hardware, and it doesn't require modern CPUs (although they were once claiming to make use of it, which was simply false - http://www.parallels.com/eu/news/id,7174).

Why do I prefer KVM? My #1 reason: A clean guest isolation, backed by modern CPUs. OpenVZ is an advanced container/jail technology, nothing more nothing less. As CPUs get even more powerful and hardware virtualization/para-virtualization even more advanced and refined, I don't see OpenVZ to stand a chance to compete against KVM, Xen, VMWare, etc. in the long run.

Chumbi

@jarland said:
Also I'm pretty sure virtuozzo is "newer" than QEMU but I'll let you dig wikipedia for that.

Rather than looking at what's newer or older, I'd look at what is better maintained. OpenVZ by a bunch of OpenVZ advocates + a company who has a commercial interest in it, versus KVM/Qemu which is in the mainland kernel and thus, I assume, receives a lot more attention from a variety of programmers and companies (Red Hat for example).

emg

I am relatively new to VPSs and have two OpenVZ and two KVM VPSs. As an end user, they both have advantages and disadvantages.

OpenVZ Comments:

• Linux VPSs only.
• Generally less expensive than a comparably spec'd KVM VPS.
• Generally better overall performance compared with KVM. Obviously performance depends on many factors, but that is what I have observed comparing the two types.
• Serial console runs over SSH and is easy to use.
• Management control panel tools (e.g., SolusVM) let you change root password without assistance.
• Bad: OpenVZ messes with configuration changes behind your back. It overwrites and/or edits files, network settings in particular.
• Network, firewall, and VPN configuration is different than the standard versions of Linux that you might install on a physical computer.
• Bad: As has been mentioned, network devices are different (Venet vs. eth).

KVM Comments:

• Supports Linux, but also many other operating systems, including Windows, BSD, Solaris, etc.
• OS installation, setup, and operation are very much like a physical computer. This is a major plus for KVM, and is probably the reason many people prefer it over OpenVZ.
• Serial console access runs over non-secure VNC, and you must still login to the VPS over that link (see losing root access, next item). When you're done, you should use a secure connection to change whatever passwords you used to connect over that link (VNC, root, etc.).
• If you lose root access (e.g., forget the root or sudo password), there is no simple fix. You might try opening a ticket with the VPS provider to help you, but you can't do it yourself, other than reinstalling the OS and starting over.

jar

@Chumbi said:
Rather than looking at what's newer or older, I'd look at what is better maintained. OpenVZ by a bunch of OpenVZ advocates + a company who has a commercial interest in it, versus KVM/Qemu which is in the mainland kernel and thus, I assume, receives a lot more attention from a variety of programmers and companies (Red Hat for example).

Preference is important. But one is not inferior to the other here by any universal standard. It is simply incorrect to make a blanket statement that openvz providers don't care about their clients because they use openvz, and that is my point.

Mark_R

@Zen said:
He isn't, you speak utter crap in 99% of your posts, sorry buddy.

To be honest, i think its pretty damn low of you that you try to get at a personal level instead of staying on-topic. Just for your information, i recently joined LET, if im full of "utter crap" then i wouldn't have been thanked 46 times in such a short time period.

Thanks for being a total dick, much appreciated.

Chumbi

@emg said:

• If you lose root access (e.g., forget the root or sudo password), there is no simple fix. You might try opening a ticket with the VPS provider to help you, but you can't do it yourself, other than reinstalling the OS and starting over.

Most KVM VPS offer VNC access + ISO mounting. With this, and some knowledge how to reset a root password (e.g. https://wiki.archlinux.org/index.php/Password_Recovery), you can do it yourself.

c0y

It's a bit of human philosophy: those who actually complain about OVZ being so much worse than KVM are usually aware of OVZ's poor design (or are just KVM fanboys).

The people who don't even know the difference obviously won't complain about OVZ, so all you see is KVM users complaining about OVZ, but that doesn't mean the majority dislikes OVZ/prefers KVM.

The ones that don't like OVZ (I like it, but not in production) will more often voice themselves and try convince others wherest most people simply don't care and use whatever works :-P

craigb

Since you mention docker @zen for lightweight containers...worth mentioning the current implementation that relies on LXC isn't compatible with OVZ. So it's a good example how apps can drive choice (they've indicated they intend to make it compatible but not sure around priority).

@mark_r there are plenty of use cases for the cheaper OVZ offerings - i encourage you to deepen your technical understanding

The double RAM KVM (4GB) I picked up from @ultimatehostings has become my docker dev box...