Entries Tagged 'Virtualisation' ↓

Ubuntu recently change their package names for kvm.  This comment posted on qemu-0.11.0 Released provides an explanation:

qemu-kvm includes features and fixes from upstream qemu and so takes its naming scheme from upstream qemu. You can think of it as qemu optimized for kvm. Note too that qemu-kvm does not include the kernel module but only the userspace and considered to be stable.

kvm-xx on the other hand is the development branch of kvm and not considered to be stable. It’s naming scheme is arbitrary and it also takes features from upstream qemu.

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kvm-kmod is different to kvm-xx. You can think of kvm-kmod as a subset of the kvm-xx. KVM-xx = userspace + kernel where kvm-kmod is the kernel part of it and qemu-kvm is the userspace part (the guest process itself). You can apply the kvm-kmod to any distro version or linux version.. it’s just the kernel driver. However, without the userspace part, you can’t do much with it.

Here  some results from testing I did in August 2009 on  KVM with the three different disk image drivers. First a single disk system running Ubuntu x64 9.04:

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From the vmware blog:

Conclusion

A 1vCPU Xeon X5500 series based Exchange Server VM can support 50% more users per core than a 2vCPU VM based on previous generation processors while maintaining the same level of performance in terms of Sendmail latency.  This is accomplished while the VM’s CPU utilization remains below 50%, allowing plenty of capacity for peaks in workload and making an FT VM practical for use with Exchange Server 2007.

According to this thread, if you need to use the linux-image-virtual package on ubuntu then it only supports the “bus logic” scsi controller with ESX.

Need to access the ESX console with the Virtual Infrastructure Client in some remote location where your VPN does not work.  Forward ports 443, 902 and 903 with putty.  Port specifics for ESX can be found on page 179 of the ESX Server Config guide.

In my case I additionally need to forward from a boundary machine:
ssh -L 8443:localhost:443 -L 8902:localhost:902 -L 8903:localhost:903 node2

Couple useful articles from Andy Millar.

• Concise and clear explaination of linux load averages.
• Bug fix suggestion for VMware server which can hang on installation. Remove the floppy device. I’ve got another issue where a linux vm on vmware server hangs on startup and I’ll have to try this.

Image by Trey Piepmeier via Flickr

Useful article on template windows vmware images. One point of great note:

As a result of point (4), your OS disk is now perfectly aligned with the storage layer below it, increasing disk I/O performance. This is actually a server OS problem that applies to all of Microsoft’s pre-Windows Server 2008 server operating sustems, and Windows XP. A simple explanation is that systems like to write data in 64k chunks onto disks with 64k sectors. However, they create their very first chunk at only 63k in size. That means every subsequent chuck writes at least 1k to the previous sector, resulting in every read and write going to two sectors and resulting in two I/Os per operation instead of just one I/O. This is what you’ve just corrected in (4).

Nice clear video presentation about cloud computing.

Redhat has acquired Qumranet the developers of KVM. Will be interesting to see how this plays out in the Linux virtualisation world.

I haven’t tried KVM yet as I’ve been too busy and Xen is more mature – but many of the accounts I’ve read seem to indicate that for Linux its performance is very good maybe better in some cases than Xen. Management is another issue, but that is just a matter of time and development enegry.

From lwn.

Here are a couple useful ESXi hints:

• ESXi 3.5 does ship with the ability to run SSH, but this is disabled by default (and is not supported) – from.
• ESXi and what it does NOT have compared to regular ESX 3.5
• Upgrade ESX eval to ESXi.
• Some Basic ESXi questions.
• 8.04 and ESX.
• Motherboards and unsupported servers that work with ESX 3.5 and / or ESXi 3.5 Installable
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  Running ESX 3i Installable from a USB Flash Drive

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