similar to: Horrible btrfs performance due to fragmentation

Hi, 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. Here''s some stuff I got from latencytop, not sure if would be helpful:

Hi, I planned to boost my btrfs performance today. here some errors I met: my ''btrfs filesystem show'' result: ~ # btrfs filesystem show failed to read /dev/sr0 Label: none uuid: 9b9aa9d9-760e-445c-a0ab-68e102d9f02e Total devices 1 FS bytes used 36.59GB devid 1 size 49.52GB used 49.52GB path /dev/sda6 Label: none uuid: 559dec06-4fd0-47c1-97b8-cc4fa6153fa0

A) Resilver = Defrag. True/false? B) If I buy larger drives and resilver, does defrag happen? C) Does zfs send zfs receive mean it will defrag? -- This message posted from opensolaris.org

Hi, all, I got machines running continuously for long time, but then the underlying ext3 file systems becomes quite heavily fragmented (94% non-contiguous). We just don't have a chance to shutdown the machines since they are always busy.. I tried the defrag 0.70 version comes with e2fsprog package and standalone 0.73 packages, but neither help me since the defrag tool can not handle ext3.

I notice this question on the wiki/faq: https://btrfs.wiki.kernel.org/index.php/UseCases#What_is_best_practice_when_partitioning_a_device_that_holds_one_or_more_btr-filesystems and as it hasn''t been answered, can anyone make any comments on the subject Various things come to mind: a) partition the disk, create an LVM partition, and create lots of small LVs, format each as btrfs b)

I set the C (NOCOW) and z (Not_Compressed) flags on a folder but the extent counts of files contained there keep increasing. Said files are large and frequently modified but not changing in size. This does not happen when the filesystem is mounted with nodatacow. I''m using this as a workaround since subvolumes can''t be mounted with different options simultaneously. ie. one with

Hi all, i am new on btrfs, i am testing KVM on btrfs (host: kernel x86-64 3.5.3), the performance is reasonable. I have two question on defrag, can someone help me? 1. According to btrfs wiki, defragment a COW file will produce two unrelated files. Does it apply to the "autodefrag" mount option? 2. Is there any command for the fragmentation status of a file/dir ? e.g. fragment

Hi, I''ve been using btrfs for my root partition for about a month on archlinux and recently Ive started using the i3 window manager and starting X manually and I now boot to run level 3 (multi-user.target for systemd) and Ive noticed that booting archlinux on a btrfs root, there is a lot off hdd chatter after the login prompts are displayed, which doesnt happen with ext4 on root, so I

We''re going to use this flag EXTENT_DEFRAG to indicate which range belongs to defragment so that we can implement snapshow-aware defrag: We set the EXTENT_DEFRAG flag when dirtying the extents that need defragmented, so later on writeback thread can differentiate between normal writeback and writeback started by defragmentation. This patch is used for the latter one. Originally patch

Kernel 3.1-rc8 btrfs-progs-0.19 mount options: noatime,autodefrag (space_cache is enabled) There are snapshots present on the filesystem. When I do a btrfs fi defrag on a file, the file becomes much more fragmented. The end result can be a file with 20k times more fragments than before. Initially I thought the extents were just smaller but were next to each other, so I checked with both

While exploring some btrfs maintenance with respect to defragmenting I ran the following commands: # filefrag /path/to/34G.file /path/to/5.7G.file /path/to/34G.file: 2406 extents found /path/to/5.7G.file: 572 extents found Thinking those mostly static files could be less fragmented I ran: # btrfs filesystem defragment -c /path/to/34G.file # btrfs filesystem defragment -c /path/to/5.7G.file and

Here is a small btrfs vs. ext4 benchmark with kernel 2.6.37-rc1. compilebench with options -i 10 -r 30 on 2.6.37-rc1 btrfs ========================================================================== intial create total runs 10 avg 73.11 MB/s (user 0.34s sys 1.96s) create total runs 5 avg 49.53 MB/s (user 0.41s sys 1.62s) patch total runs 4 avg 22.13 MB/s (user 0.09s sys 1.79s) compile total runs

Hello all, I understand that relatively high fragmentation is inherent to ZFS due to its COW and possible intermixing of metadata and data blocks (of which metadata path blocks are likely to expire and get freed relatively quickly). I believe it was sometimes implied on this list that such fragmentation for "static" data can be currently combatted only by zfs send-ing existing

- Add incompat flag, otherwise btrfs-progs will report error when operating on btrfs filesystems mounted with lzo option. - Allow to turn on lzo compression for defrag operation: # btrfs filesystem defragment -c[zlib, lzo] <file> Note: "-c zlib" will fail, because that''s how getopt() works for optional arguments. Signed-off-by: Li Zefan

Hi folks, I''m using Ubuntu 12.10 Quantal with # uname -r 3.5.0-24-generic And it seems I cannot defrag : # filefrag /boot/initrd.img-3.5.0-24-generic /boot/initrd.img-3.5.0-24-generic: 3 extents found # btrfs filesystem defrag /boot/initrd.img-3.5.0-24-generic # echo $? 20 # filefrag /boot/initrd.img-3.5.0-24-generic /boot/initrd.img-3.5.0-24-generic: 3 extents found Any clue

Two files in the different subvolumes may have the same inode id, so The rb-tree which is used to manage the defragment object must take it into account. This patch fix this problem. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> --- fs/btrfs/file.c | 45 +++++++++++++++++++++++++++++++++++---------- 1 files changed, 35 insertions(+), 10 deletions(-) diff --git a/fs/btrfs/file.c

Hi, I have 4 machines, all converted to BTRFS about 6 months ago, now all running Ubuntu Quantal with kernel 3.5.0-17 The matter is that all these machines are now getting slower and slower everyday, every disk access causing the disk to be 100% busy for long periods, to the point that I''m now seriously considering migrating everything back to ext4... From the start BTRFS was "not

The following series implement a way to generate the help messages and the btrfs man page from the sources comments for the "btrfs" commanda . The syntax and the detailed help of every subcommand are stored in the comments before the function which implements the subcommand. The fact that the help messages and the man page are generated from the same source should help to avoid

Hey folks, Does anybody know if any of these are on the roadmap for ZFS, or have any idea how long it''s likely to be before we see them (we''re in no rush - late 2008 would be fine with us, but it would be nice to know they''re being worked on)? I''ve seen many people ask for the ability to expand a raid-z pool by adding devices. I''m wondering if it

I found this thread from a few months ago that seems to have been started by someone with the same problem I have, but it was not resolved: https://www.redhat.com/archives/ext3-users/2005-March/msg00000.html I have been trying to speed up my boot times and I notice that a lot of time is spent waiting on IO. Even with readahead-list precacheing files, it is reading at less than 1/4 of my