On 03/27/2011 09:00 AM, Jerry Franz wrote: > > On 03/27/2011 02:57 AM, Jussi Hirvi wrote: >> > Some may be bored with the subject - sorry... >> > >> > Still not decided about virtualization platform for my "webhotel v2" >> > (ns, mail, web servers, etc.). >> > >> > KVM would be a natural way to go, I suppose, only it is too bad CentOS 6 >> > will not be out in time for me - I guess KVM would be more mature in >> > CentOS 6. >> > >> > Any experience with the free "VMware vSphere Hypervisor"?. (It was >> > formerly known as "VMware ESXi Single Server" or "free ESXi".) >> > >> > http://www.vmware.com/products/vsphere-hypervisor/overview.html >> > >> > I would need a tutorial about that... For example, does that run without >> > a host OS? Can it be managed only via Win clients? Issues with CentOS >> > 4/5 guests (all my systems are currently CentOS 4/5). > I'm currently using Ubuntu Server 10.04-LTS as a host for KVM running > CentOS5.5 guests I migrated from VMware Server 2. Works fine. A nice > feature of current generation KVM is that you are supposed to be able to > do live migration even without shared storage (although I haven't tested > that yet). I wrote some custom scripts to allow me to take LVM snapshots > for whole-image backups and I'm pretty happy with the who setup. > > The only corners I encountered were > > 1) A lack of documentation on how to configure bridging over bonded > interfaces for the host server. It turned out to be fairly easy - just > not clearly documented anyplace I could find. > > 2) The default configuration for rebooting/shutting dow the host server > just 'shoots the guests in the head' rather than having them shutdown > cleanly.:( You will want to write something to make sure they get > shutdown properly instead. > Once in a while I find it's useful to compromise just a little, so I use Scientific Linux 6 as the Host OS, and run a bunch of CentOS-5.5 Guest VMs. It all simply works. KVM has improved quite a bit, and the management tools work well. One thing that requires a bit of skill is getting bridging configured (which I simply did by hand from the RHEL-6 documentation). I'm happy with the result, and see no reason to replace the underlying SL-6 Host distro. SL-6 as the Host is rather slow to shut down gracefully and reboot, because it hibernates the Guest OSs, one at a time, rather than just killing them. Hibernation takes a while to write out to disk if you've assigned a lot of RAM to the Guests. Bootup has to restore the saved state, so that's a bit slow too. But it works very well. I use partitionable RAID arrays for the Guests, and assign a "raw" md device to each one rather than using the 'filesystem-in-a-file' method. It seems to be a bit faster, but there's a learning curve to understanding how it works. One thing I found a bit annoying is the very long time it takes for a Guest to format its filesystems on the RAID-6 md device assigned to it. That's mostly due to array checksum overhead. RAID-10 would be a *lot* faster but somewhat less robust ... you pick what's best for your own situation. Chuck