On Mon, Oct 11, 2010 at 6:46 PM, Calvin Walton <calvin.wal...@gmail.com> wrote: > On Mon, 2010-10-11 at 03:30 +0300, Felipe Contreras wrote: >> I use btrfs on most of my volumes on my laptop, and I've always felt >> booting was very slow, but definitely sure is slow, is starting up >> Google Chrome: >> >> encrypted ext4: ~20s >> btrfs: ~2:11s >> >> I have tried different things to find out exactly what is the issue, >> but haven't quite found it yet. > > If you've been using this volume for a while, it could just have become > badly fragmented. You could try btrfs's fancy online defragmentation > abilities to see if that'll give you an improvement: > > # btrfs filesystem defragment /mountpoint/of/volume > > Let us know if that helps, of course :)
I finally managed to track down this issue. Indeed the fragmentation is horrible, and 'btrfs filesystem defragment' doesn't help: % cat History-old > History % btrfs filesystem defragment /home % echo 3 > /proc/sys/vm/drop_caches % time dd if=History of=/dev/null && time dd if=History-old of=/dev/null 109664+0 records in 109664+0 records out 56147968 bytes (56 MB) copied, 1.90015 s, 29.5 MB/s dd if=History of=/dev/null 0.08s user 0.29s system 15% cpu 2.458 total 109664+0 records in 109664+0 records out 56147968 bytes (56 MB) copied, 97.772 s, 574 kB/s dd if=History-old of=/dev/null 0.07s user 0.80s system 0% cpu 1:37.79 total I think this is a serious issue that *must* be fixed for 1.0. I filed a bug for this: https://bugzilla.kernel.org/show_bug.cgi?id=21562 -- Felipe Contreras -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
