Am Donnerstag, 31. Januar 2013 schrieb Hugo Mills: > On Thu, Jan 31, 2013 at 02:44:12PM +0100, Martin Steigerwald wrote: > > Hi! > > > > Today I converted my /home from Ext4 to BTRFS by reformatting and copying > > all over again. > > > > I created the filesystem with -l 16384 -n 16384 -d single -m single on an > > logical volume Intel SSD 320 and mount with compress=lzo,spacecache. > > Current state: > > The way that compression is implemented in btrfs, compressed files > always look fragmented, even if they're not. Basically, each > compression block shows up as a single fragment. If the blocks are > next to each other, the file's not actually fragmented, but still > looks like it to fiemap.
Ah, thanks. Thats interesting to know. > [snip] > > Except for a highly fragmenting file: > > > > martin@merkaba:~/.kde/share/apps/nepomuk/repository/main/data/virtuosobackend> > > ls -lh > > insgesamt 1,2G > > -rw------- 1 martin martin 1,3G Jan 31 14:07 soprano-virtuoso.db > > -rw-r--r-- 1 martin martin 14 Jan 31 14:06 soprano-virtuoso.lck > > -rw------- 1 martin martin 0 Jan 27 17:52 soprano-virtuoso.lock > > -rw-r--r-- 1 martin martin 13K Jan 31 10:22 soprano-virtuoso.log > > -rw-r--r-- 1 martin martin 0 Jan 27 17:52 soprano-virtuoso.pxa > > -rw-r--r-- 1 martin martin 8,0M Jan 31 14:07 soprano-virtuoso-temp.db > > -rw-r--r-- 1 martin martin 14K Jan 31 14:07 soprano-virtuoso.trx > > > > > > martin@merkaba:~/.kde/share/apps/nepomuk/repository/main/data/virtuosobackend> > > sudo filefrag soprano-virtuoso.db > > [sudo] password for martin: > > soprano-virtuoso.db: 481 extents found > > […] > > > Now I do not perceive any bottle neck so far and this is an SSD. > > > > What would be your recommendation: Add autodefrag to mount options or not? > > For an SSD, probably not worth it. Thanks. I then will use what I advice attendees to my Linux Performance Analysis & Performance trainings and what XFS guys are also advicing: Use the defaults (unless you know otherwise). Especially since I think the Intel SSD 320 is one of the better ones and desktop search is really snappy up to know. Thanks, -- Martin 'Helios' Steigerwald - http://www.Lichtvoll.de GPG: 03B0 0D6C 0040 0710 4AFA B82F 991B EAAC A599 84C7 -- 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
