A copy-on-write (COW) file system developed by Oracle included in the Linux kernel.

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How to delete a directory with multiple btrfs subvolumes?

My root file system is on a btrfs partition. My /chroot directory has a number of btrfs subvolumes in it which prevent me from deleting it with rm -rf /chroot. In an attempt to delete all the ...
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170 views

RAID: ZFS or Btrfs?

I've mounted my own NAS with ArchLinux on an old HDD. I want to add 3x4To to have real storage capabilites and I would like to use a RAID5 system with these 3 disks. I've read a lot about ZFS Raid-z ...
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267 views

Restore Btrfs snapshot from subdirectory to parent

I have a Btrfs partition which has a single subvolume at the top level (/root). It has subvol=root option in /etc/fstab. Every week, I take a readonly snapshot into /root/snapshots/... using: btrfs ...
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58 views

How to find the amount of shared extents on btrfs?

What command can I use to see the amount of shared extents on a btrfs volume. Or better yet, what command gives me the logical size used along with the on-disk size of all extents together?
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235 views

List all btrfs filesystems and subvolumes in shell

Is there a convenient way to get information on all btrfs filesystems subvolumes without resorting to C, i.e. in POSIX shell ? /sys/fs/btrfs contains info only on filesystems, nothing on subvolumes, ...
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637 views

Compiling and running Snapper for Ubuntu

I am trying to get snapper working in my Mint 14. (The version from launchpad is old and not compatible with Ubuntu 12.10. The OpenSuSe's build project failed to build it, too). So I try my luck with ...
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60 views

BTRFS has become unmanageable

I'm struggling with a btrfs RAID0 filesystem. It's expanded on 4 disks but i need to remove one of those disks. This is the current status of the filesystem: [root@osgiliath detlev]# btrfs fi show /...
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215 views

BTRFS: too many missing devices, writeable mount is not allowed

Environment $ btrfs --version btrfs-progs v4.2.1 $ uname -a Linux [REDACTED] 4.2.1-040201-generic #201509211431 SMP Mon Sep 21 18:34:44 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux Problem Today the ...
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35 views

Can I determine the exclusive space usage of groups of btrfs subvolumes?

I want to free up some space in my btrfs filesystem by deleting some snapshots. But I cannot work out which ones would be effective to delete. This question's answer explains how to show the amount of ...
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32 views

List reflink filenames to a file on btrfs

Given a path/filename on a btrfs filesystem, how can you see the other reflinked path/filenames to the same file?
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319 views

Running a btrfs RAID 5 array on Arch Linux

For two weeks, I've been trying to run my Raspberry Pi (model B) as root from a btrfs RAID 5 without success. The RAID runs on three 1TB disks /dev/sda, /dev/sdb and /dev/sdc. The three disks were ...
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562 views

How does enabling btrfs quotas impact the system?

I use btrfs snapshots quite a bit, and one of the things that interests me is how much space a given snapshot takes up - or to be more specific - how much exclusive data a btrfs snapshot is taking up, ...
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88 views

Configure where GRUB2 environment block is located

I have Arch, Ubuntu, and GRUB2 installed on a BTRFS filesystem. I'm aware that GRUB cannot write to BTRFS for a variety of good reasons, and therefore cannot save environment variables to /boot/grub/...
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141 views

On which disk is a file located in a btrfs RAID-1 array/filesystem?

I have a btrfs array with 5 disks in RAID-1 mounted on /mnt/array: # btrfs filesystem show /mnt/array Label: 'nicefilesystem' uuid: censored Total devices 5 FS bytes used 4.95TiB ...
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44 views

How much space would be freed by removing a btrfs subvolume?

Is there any way to calculate how much space I would free if I would remove one (or several) subvolumes on a Btrfs disk (without actually removing them)? I know that there is "currently no code that ...
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268 views

LXC with both GUI apps and snapshots on unmodified Fedora kernel

I am looking for a tool or library to run LXC that supports: running X applications conveniently snapshotting root filesystems (using a Fedora system with an unmodified kernel), so that I don't have ...
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166 views

How does SuSE Linux's support for btrfs differ from Ubuntu and Fedora's?

The SuSE Linux Enterprise Server 11 Service Pack 2 release notes state that SuSE offers "commercial support" for btrfs, while Ubuntu and Fedora appear to be holding back until a working fsck utility ...
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36 views

Btrfs adding smaller drive to RAID1

I have a RAID1 btrfs filesystem with 2 2Tb drives, and I had a spare 750 Gb hdd lying around, so I thought I would add it to the RAID so I could use some extra storage. Well, I added it to the volume,...
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30 views

Mounting a (semi-?) rebalanced btrfs drive

Have a 2 drive raid1 btrfs array on Ubuntu 16.04 that I no longer need to be raid1. Thought I would try separating the the disks and converting one to a single drive to keep the data following these ...
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38 views

Space efficiency of Btrfs reflinks vs hardlinks

A webpage referenced by the Wikipedia article on Btrfs claims that (emphasis mine) [Btrfs] reflinks have the same use as hardlinks, but are more space efficient. I thought that the opposite was ...
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120 views

Copy remote btrfs incremental snapshot to new drive w/ UUID

Situation: Two machines (A & B, with local drives dA & dB) connected via slow network. Drive dA has initial backup to dB, while locally attached on machine A. btrfs send RO-snapshot-1-dA | ...
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29 views

Modifying a file “pointed” to by a lot of snapshots

I'm using btrfs and snapper. So, I have many periodic btrfs snapshots, which are marked read-only (can of course be changed by btrfs to r/w and changed back.) Let's say during my initial install I ...
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58 views

btrfs device add: different mount options than for seed?

I have a btrfs seed device, created with mixed data+metadata (mkfs.btrfs --mixed), and also --metadata single. This device is read-only. When doing btrfs device add /dev/sdc1 /mnt, is it possible to ...
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105 views

What can I do with btrfs “profiles”?

Reading through the btrfs (sub) command documentation, it can "balance only block groups with the given replication profiles", and "convert selected blocks to a given profile", and apparently it ...
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84 views

Btrfs: Is there an easy way to find a file by block numbers it occupies?

Say, you have filesystem Btrfs formatted, then you, all of the sudden as it happens, wonder — what files occupy blocks #356 and #789, how you gonna answer this question?
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110 views

BTRFS - Raid incomplete after balancing

I have two 3TB drive that are formated as btrfs and mounted on /media/andy/btrfs as one drive. I run btrfs balance start -dconvert=raid1 -mconvert=raid1 /media/andy/btrfs/ which takes forever. It ...
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199 views

How do I align my new btrfs default subvolume with the real root of my filesystem?

I rolled back my system by using snapper rollback Unfortunately this caused my current default volume to not be at the root of my filesystem anymore. As you can see in this screenshot: The ...
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728 views

“cache and super generation don't match, space cache will be invalidated” what does this means and how to repair it?

I'm having a little problem trying to grow a btrfs partition in my system, namely: sudo btrfsck /dev/sdb9 [sudo] password for braiam: Checking filesystem on /dev/sdb9 UUID: f7e9ac38-5068-4c55-97ab-...
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477 views

System cannot boot, continiously scanning btrfs filesystem

On the previous boot I installed HAL to make amazon prime video streaming work, which it did (mostly), but after reboot the system could not pull itself up all the way to BASH and drops to a failed ...
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13 views

What do “snapper mount” and “snapper umount” do?

I'm using snapper with BTRFS under Ubuntu 16.04, and I'm confused about the "mount" and "umount" parameters. They are documented like this in the man page: mount number Mount a snapshot. ...
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20 views

IO Error when trying to create a Btrfs snapshot

In Fedora 23, my / partition is formatted as Btrfs: /dev/nvme0n1p4 / btrfs rw,seclabel,relatime,ssd,space_cache,subvolid=257,subvol=/root 0 0 Full output: $ sudo cat /proc/mounts sysfs /sys sysfs ...
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37 views

Possible slab memory leak related to bio and btrfs?

I'm currently running a rebuild on a btrfs NAS (~20TB) that had a drive failure. It's going to take a few days. My problem is about once every 24 hours the RAM filled up and the kernel starts killing ...
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41 views

Btrfs - Using Flash Drive as Backup/Snapshot Location

I am working on a project where I have a small MiniITX PC running Debian Jessie (8.3) When I installed the OS initially: I chose the filesystem as btrfs. I am not using LVM or any extra partitions ...
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18 views

Snapper - how to undo changes, preserving timestamps?

I've damaged modification dates of files on my drive and I wanted to revert them using snapper snapshots but it doesn't seem to work, snapper only reverts content of files not modification dates. ...
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52 views

BTRFS reports errors, but the drives don't. Do I have failed drives?

I have been using btrfs for over a year, and noticed reports of lots of errors in the logs but no problems. A recent scrub found HUGE numbers of csum errors, by huge I mean 85 MILLION, however scrub ...
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55 views

Udisks2, LUKS and btrfs

I just bought a portable USB HDD,on which i put 2 partitions : a LUKS one, which contains a btrfs fs and a fat32 one, in case I'd have to use a system which doesn't support LUKS or btrfs I use ...
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251 views

BTRFS RAID6 array is broken, how do I fix it?

I have a server running a btrfs raid 6 array which seems to have broken. When try to mount it I get the following error message. I don't know how or why it broke maybe a power outage or something (it ...
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146 views

Display btrfs subvolume tree

Is there a way to make a btrfs subvolume tree like what is shown below? (Only subvolumes - no regular directories or files.) # tree /mnt/1 /mnt/1 ├── a ├── snapshot │ ├── a │ └── subv └── subv ...
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467 views

ssd caching in loop device on btrfs

I have an ssd and 2TB hard disk. The ssd is used for the root filesystem which uses only around 20G of the 120G available. Is there a way to use an image/loop on the root filesystem (btrfs) as a cache ...
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97 views

BTRFS - removing drive by devid instead of path

I recently lost a 5 TB drive using btrfs. I had a system freeze (unsure why) while a balance was running. My SMR drive got corrupted. I was able to mount my array degraded and balance my data. However,...
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36 views

Formatting btrfs for robust metadata

If I make three partitions on a HDD, it appears that the default (which is -m raid1) will only store two copies of each metadata block. Is there a way to store multiple copies, e.g. one on each ...
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131 views

When using btrfs, why “Size”, “Used” and “Avail” values from df do not match?

I have similar problem like unix.stackexchange.com/questions/37489/ btrfs filesystem show Label: none uuid: 3fdeaf6d-ca88-4cc8-8405-f882f02693f7 Total devices 3 FS bytes used 1.53MB devid ...
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346 views

Recover data from a BTRFS RAID5

I have a BTRFS RAID5 setup (no mdadm) with four disks (the fifth failed). Now I am trying to recover the files but as soon as I try to rsync the files over to another disk, the system hangs after ...
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62 views

btrfs partition not detected

I have some distros installed on a BTRFS partitions under different subvolumes ( for distro-hopping, separate ext4 boot). This btrfs partition is now not getting detected on boot, while I can access ...
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64 views

What are the linux kernel versions incompatibilities with btrfs?

I read that usage of a btrfs volume with a newer kernel can render it unreadable when that same volume is used with an older kernel. I have a mobile storage device that will be used by different linux ...
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28 views

Does changing your OS (fedora>OpenSuse) or FS (ext4>btrfs) “break” rsync?

I am using a rather simple script to do incremental backups of my laptop to my external HDD's, where the core line is probably the following: rsync -arbuv --delete --progress -exclude-from=/backup-...
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39 views

hidden directories to ls (not dot prefixed file)

I'm facing with a uncommon issue, which is: After btrfs read failure and a btrfs check --repair on my partition mounted in /home, it seems that some directories have disappeared. I explain : When I ...
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33 views

why stat() can't get the real device number for ubifs

the man 2 stat struct stat { dev_t st_dev; /* ID of device containing file */ ino_t st_ino; /* inode number */ mode_t st_mode; /* protection */ nlink_t ...
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13 views

Cryptsetup boot many devices “timeout”

On my server, the crypttab file has 13 entries for every hard drive connected to it. 2 are for the system partitions, 2 are for the backup system and 9 are for the mediaserver and nfs stuff. Currently,...
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19 views

btrfs - how to list files stored in a block?

I have some troubles with my btrfs file system on Ubuntu (my partition automatically enter in read-only mode after the login screen). I would like to know if one can know which files are included in ...