Migrating to ext4
To celebrate the stabilization and release of Ubuntu 9.04, I’ve destabilized my primary (work and personal) laptop a bit by migrating from ext3 to ext4, following (more or less) the procedure I found on the ext4 wiki. I created a fresh 9.04 USB stick with usb-creator, booted it, ran the procedure, mounted the filesystem, updated /etc/fstab, and rebooted from the internal disk.
In order to try out the delayed allocation feature, I re-allocated (via cp/mv) some parts of my disk which I thought might benefit from being less fragmented, such as:
- *.sqlite in my Firefox profile directory (urlclassifier3.sqlite went from hundreds down to 3 extents)
- the .iso files I use for testing Ubuntu in KVM (ubuntu-9.04-desktop-i386.iso went from 2391 down to 71)
- my mutt cache (discovering in the process that it now uses a different format, so I couldn’t compare)
(note: filefrag(8) will tell you how fragmented a file is)
I expect that defragmenting my system libraries and other startup data would get my system booting a bit faster, but I think I’ll just let that happen naturally when I upgrade to Karmic.
I did some stress testing by running a large offlineimap update while starting up Firefox and deleting some large files, and was rewarded with a solidly frozen system (no network response, no caps lock, no response to SysRq). I could not get any information about the cause of the crash, though the proximity to the ext4 switch is certainly suspicious…
Onward to Karmic!