similar to: Defragmentation of large files

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

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: merkaba:~> btrfs filesystem show failed to read /dev/sr0 Label: ''home'' uuid: […] Total devices 1 FS bytes used

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

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

Someone recently posted the following statement midway down the page at http://forums.gentoo.org/viewtopic-t-305871-postdays-0-postorder-asc-highlight-ext3+ordered+data-start-25.html >You don't need to defragment ext2/ext3 because as you use the >filesystem file blocks and inodes are moved around and reallocated >to keep the data nearly contiguous. It's not perfect, but it

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

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

Hi, I am new to btrfs, and just installed a new system with SLED 11 SP2 a few days ago. However the system seems to be in a real sad state now, saying there is no free space left on the device even though there is about 8GB left on the / filesystem. A defragment works sometimes but then it goes back to the original state a day or two later. Other times the command just won''t respond.

Hi, I have btrfs volume, shared via samba. I have a directory of documents that I want to backup on my server. win7 reports a maximum of ~3.10MB/s transfer transferring the same directory on a ext4 samba share I get 25MB/s + Any ideas? Is it like that because of how btrfs works and is setup? Thanks, -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body

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

Hi, first of all, apologies if this isn't the right mailing list but it was the best I could find. If you know a better mailing list, please tell me. Today I tried to defrag one of my filesystems. It's a 3.5T large filesystem that has 6 software-raids in the bottom and then merged together using lvm. I was running ext3 but removed the journal flag with thor:~# tune2fs -O ^has_journal

Hello everybody, reading about the speed improvements possible with (on boot) preloaded files (which should be continuous on disk) I searched for a ext3 defrag program. I found an ext2 defrag program (http://www.ibiblio.org/pub/Linux/system/filesystems/defrag-0.70.tar.gz, available in debian as defrag) which would have an optimal feature (moving files by a list) but refuses to work on ext3.

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

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

This commit fixes three issues on non-auto defrag path (defragfs.ocfs2 doesn't set OCFS2_MOVE_EXT_FL_AUTO_DEFRAG on range.me_flags): - For ocfs2_find_victim_alloc_group(), old code forgot enlarge bitmap range for global_bitmap case. Old code could generate negative vict_bit. - For ocfs2_probe_alloc_group(), old code forgot back off move_len when finding enough bitmap space. Old code has

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

This fixes three issues on move extents ioctl without auto defrag: a) In ocfs2_find_victim_alloc_group(), we have to convert bits to block first in case of global bitmap. b) In ocfs2_probe_alloc_group(), when finding enough bits in block group bitmap, we have to back off move_len to start pos as well, otherwise it may corrupt filesystem. c) In ocfs2_ioctl_move_extents(), set me_threshold both for

I came across the tidbit that ZFS has a contract guarantee that the data read back will either be correct (the checksum computed over the data read from the disk matches the checksum stored on disk), or you get an I/O error. Obviously, this greatly reduces the probability that the data is invalid. (Particularly when taken in combination with the disk firmware''s own ECC and checksumming.)

I've read in many places that file systems on Linux do not suffer the same fragmentation problems of Windows systems. No one has provided a clear explanation as to why fragmentation is not an issue for file systems such as ext2/3, reiserfs, xfs, etc. Just curious.