Posted by Fraser Campbell
Tue, 27 Feb 2007 13:05:00 GMT
Ulrich Drepper is lead maintainer of the Linux C library (GNU libc), works for Red Hat and is well known in Linux circles – basically he is one smart cookie.
Last night he has posted a great article entitled Xensource/VMWare start sandbagging.
The article discusses the fact that Linux already has great support for NUMA, SMP, scheduling, hardware drivers, etc. My favorite “As for better scheduling with a hypervisor: that can only be a joke.”.
We can expect the marketing machines to crank out reams of verbage in the next 6 months but I trust Mr. Drepper more than I would trust anything I see coming from the corporate presses.
Linux as the hypervisor just makes sense. Jeff Dike has been pushing the idea for years with UML and UML continues to move forward.
The only slight beef (or question) I have with KVM is why has it diverged from QEMU? More specifically KVM relies on QEMU for it’s device emulation but it also requires hardware virtualization. Now that QEMU’s kernel accelerator is open source could KVM and QEMU not be merged back together to give us one high performing solution that would support both VT and non-VT capable hardware?
Posted in Xen, XenSource, QEMU, VMware, KVM | 2 comments
Posted by Fraser Campbell
Tue, 06 Feb 2007 23:46:00 GMT
With the just announced open sourcing of the QEMU accelerator it would be interesting to have some idea of the performance differences between QEMU, QEMU + accelerator and KVM.
It turns out that someone has already done the hard work for us. See http://linux.inet.hr/ article Finally user-friendly virtualization for Linux.
KVM and QEMU with it’s accelerator both appear to be capable of utilizing CPU and memory at close to native speeds (perhaps 80%). Definitely worth another look on the laptop.
Posted in QEMU, KVM | no comments
Posted by Fraser Campbell
Tue, 06 Feb 2007 23:39:00 GMT
Today a new version of the QEMU accelerator was released. There are some new features but the most noticeable change is that the module is now open source (GPL version 2). See announcement on the QEMU News page.
This move is not too surprising considering that there are now so many open source virtualization solutions for Linux. Fabrice has done a great favour to so many projects – Win4lin, KVM, Virtualbox and Xen all use QEMU in some form – let’s hope he can continue to hack on QEMU and be rewarded for it.
Besides the license change another noteable feature of the updated code is full x86_64 virtualization support.
With the relatively high performance CPU emulation provided by KQEMU I wonder if we might not see Xen patched eventually to provide full virtualization support without VT extensions?
Posted in QEMU | no comments
Posted by Fraser Campbell
Sun, 21 Jan 2007 04:18:00 GMT
QEMU has to be the king of open source virtualization:
- Xen uses QEMU for device emulation in non-paravirtualized operating systems (HVM)
- KVM uses QEMU, same reason as Xen
- finally the recently open sourced VirtualBox also uses QEMU
Qemu currently does not support any migration capability natively athough Qumranet has added “dead migration” capability to their patched version.
Anthony states that he doesn’t like the approach KVM has taken to migration and goes further to say:
The biggest problem I have with KVM and Xen’s migration is that it uses open TCP ports. This is just such a bad idea.
It is easy to agree with this statement.
Anthony has designed a migration system for QEMU that let’s the user define how the migration happens (for example an encrypted and securely authenticated SSH channel).
Here’s hoping that ideas like this start to filter into Xen down the road, depending on a “private” management network for security isn’t the best option for sure.
Anthony’s original post can be read on his blog here and he includes links to the QEMU patches.
Posted in QEMU | no comments
Posted by Fraser Campbell
Fri, 04 Aug 2006 19:11:00 GMT
I have posted a question to the Xen-devel list to see if there are any known fixes for my issue with b44 network driver. I’m not holding out a lot of hope for an immediate solution so I decided to try something else. QEMU.
If you haven’t heard of QEMU it is an open-source processor emulator, QEMU is also part of the technology used by Xen in order to boot unmodified guests. You can get more information on the QEMU website at http://fabrice.bellard.free.fr/.
Read more...
Posted in Xen, Ubuntu, QEMU | no comments
