On Thursday 18 August 2011, Tixy wrote:
Mystery solved...
I didn't have btrfs-tools (nor nilfs nor logfs) installed. My test script didn't notice that mkfs failed because I was piping the output through tee, (which, being the end of the pipeline, always gave a success result).
This all resulted in my tests being re-run on the last file system (ext2) which is a interesting result in itself as it shows a lot worse performance compared to a fresh partition. (This is the sort of thing we expected and is on the list of things to investigate further.) My new results for the untar on a Beagleboard-xM...
ext4 161s ext3 547s ext2 256s btrfs 139s nilfs 157s
Ok, that is certainly an interesting and more logical result. ext3 is worse than ext2 because of the journal. ext4 has optimizations for flash media in it and btrfs is better by design.
I couldn't test logfs because, whilst mkfs worked, the mount command (or the kernel?) doesn't seem to support it.
Probably the module was not enabled in the kernel.
I also tested the different btrfs mount options (ssd, nossd and ssd_spread). They don't show much difference with the untar case.
Ok.
Arnd