On 23 February 2016 at 18:26, Marc MERLIN <m...@merlins.org> wrote: > > I'm currently doing a very slow defrag to see if it'll help (looks like > it's going to take days). > I'm doing this: > for i in dir1 dir2 debian32 debian64 ubuntu dir4 ; do echo $i; time btrfs fi > defragment -v -r $i; done [snip] > Also, should I try running defragment -r from cron from time to time?
I find the default threshold a bit low and defragment daily with "-t 1m" to combat heavy random write fragmentation. Once in a while I defrag e.g. VM disk images with "-t 128m" but find higher thresholds mostly a waste of time. YMMV. > But, just to be clear, is there a way I missed to see how fragmented my > filesystem is without running filefrag on millions of files and parsing > the output? I don't think so, and filefrag is slow with heavily fragmented files because ioctl(FS_IOC_FIEMAP) is called many times with a buffer which only fits 292 fiemap_extents. -- 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
