Ubuntu
Ubuntu upgrades and BTRFS snapshots
One of my VMs is running Ubuntu with BTRFS on the boot disk. During an Ubuntu upgrade, I noticed a significant increase in disk space usage, and it turns out Ubuntu created a snapshot on my BTRFS volumes. Now, this is pretty neat, but once I verified everything was working fine, I wanted to delete the old snapshot. It turned out to be a bit more trickier than I though, but with some help from Sami Haahtinen, I got it to work. First, to list the sub volumes, I did
ubuntu-server (16:07) 3/0 $ sudo btrfs subvolume list / ID 256 top level 5 path @ ID 257 top level 5 path @home ID 258 top level 5 path @apt-snapshot-release-upgrade-oneiric-2011-10-13_12:41:44
The next step, which was crucial, is to "mount" the full disk BTRFS is using, without specifying a sub-volume:
ubuntu-server (16:09) 4/0 $ sudo mount /dev/mapper/ubuntu--server-slash /mnt
Your disk name will obviously differ (most likely), but after this, you can now delete this sub-volume:
ubuntu-server (16:09) 5/0 $ cd /mnt
ubuntu-server (16:10) 6/0 $ sudo btrfs subvolume delete '@apt-snapshot-release-upgrade-oneiric-2011-10-13_12:41:44'
Upgrading Ubuntu from command line
Ubuntu 11.10 was just released, and I eagerly decided to upgrade my "server' VM to "Oneiric Ocelot". My installation has no GUI, so I could not use the normal tools I'd use to do the live upgrade. So instead, I had to figure out the command line tools to use. Now, this is well documented, but is still worthwhile to repeat.
$ sudo apt-get install update-manager-core $ do-release-upgrade -d
That's pretty much it, just follow the destructions on the screen (oh, and recommended not to do this over an ssh session).
VirtualBox and Ubuntu 10.10
VirtualBox v3.2.10 has just been released, and I have confirmed that the guest additions with this release works with Xorg 1.9 that comes with Ubuntu 10.10. I've succesfully installed the guest additions on both the 32-bit and 64-bit versions.
Comparing different Unix distributions performance
Introduction
This is an ongoing set of benchmarks against various Unix (Linux, Solaris, MacoSX etc.) distributions, trying to get a feel for how they compare on CPU performance. This is by no means a complete test, I'm only running a few benchmarks on each distribution, and I'm primarily only looking at raw CPU performance. Also, in order to make this reasonably easy for me to handle, all tests are done inside a VirtualBox virtual machine, and only one CPU is ever used (meaning, the tests don't show how well the Unix flavor manages SMP.
Setup
The test system is a Linux FC9 box, with a Core2 6600 CPU running at 2.40GHz, with 4MB of cache. Each Unix distribution is installed in a VirtualBox (v2.10) virtual host, with 512MB of RAM (plenty for all tests). All Linux distributions were updated with all the latest patches available at the time of the test, running whatever kernel, compilers and libraries available at the time.
Benchmarks
Each benchmark is run three times on each distribution, and the best result is picked from each test. Currently the only benchmark I run is the ByteMark, called nbench. The source for this is available at http://www.tux.org/~mayer/linux/bmark.html . As mentioned before, this not only benchmarks the kernel, it also exercises the compiler suite, and supporting libraries (e.g. glibc). But then again, someone picking a distribution probably wants to see the "whole picture", right?
Next steps (and caveats)
I'm planning on running lmbench on these machines as soon as possible, to see if those numbers shows any more significant differences. I'm also planning on adding benchmark results for SUSE, which is a popular Linux distribution. Unfortunately I can't test MacOSX on this hardware, since I can't install it under VirtualBox. In particular, lmbench would probably be more useful without Virtualization, for testing how well the system behaves on things like disk I/O, network and SMP scalability.
With time permitting, and if/when I can free up the hardware, I think it'd be useful to do these benchmarks without virtualization involved. It's unclear today what impact VirtualBox has on these benchmarks (but, I'm hoping it's relatively fair across all the distributions). When Michelle lets me upgrade my desktop, I'll use the old system for rerunning these tests.