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

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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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17 views

How do I layer compression on top of encryption on top of BtrFS, per-file?

BtrFS should support this really, but it doesn't. So ECryptFS looks like it will fill the gap. The only thing is, how would I layer compression on top of this? Reasons for compression on top of ...
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8 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 ...
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20 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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1answer
42 views

Clear all Snapper snapshots

OpenSUSE (among other distributions) uses snapper to take snapshots of btrfs partitions. Some people think the default snapshot intervals take up too much space too quickly, but whether or not you ...
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1answer
47 views

Mount options for BTRFS on an external USB drive

I've formatted my external HD with BTRFS (aware of the risks). What are options I should use to increase failure tolerance on sudden power loss to the drive?
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25 views

Defrag range ioctl not supported in this kernel, please try without any options

I'm trying to compress my BTRFS filesystem for all the files I added before adding compress=lzo to /etc/fstab. I've booted into a live CD and run the following: sudo mount /dev/mapper/root /mnt sudo ...
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1answer
102 views

install with BTRFS: subvolume/partition scheme?

I'm fairly new to both GNU/Linux and btrfs, but I've decided I want to make my next computer (a desktop with one HDD) use Linux with btrfs as the filesystem. However, I've seen some advice online that ...
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2answers
276 views

Slow access to btrfs on LVM/

We have this setup on our server: Ubuntu 14.04 (used to be 12.04) 10TB RAID-6 system LVM (one VG, two LV) ext4 partition ( ~2TB) Btrfs partition ( ~8TB) After a reboot last month the system was ...
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46 views

ideal btrfs storage scheme to incorporate external USB HDD as backup media

Is there a way to leverage btrfs's advanced features (COW, snapshots, etc.) to continuously backup/mirror my main storage volume to an external USB HDD?
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1answer
197 views

Path `/boot/grub' is not readable by GRUB on boot. Installation is impossible. Aborting

Whenever I try updating grub, I get this error: # grub-install /dev/sda Path `/boot/grub' is not readable by GRUB on boot. Installation is impossible. Aborting. and # grub-mkconfig -o ...
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1answer
213 views

Resize a btrfs partition inside a logical LVM volume

Following derobert's trick to resize the underlying filesystem when resizing a LVM volume: lvm> lvextend -r -l +100%FREE /dev/VolGroup00/lvolhome fsck from util-linux 2.25.2 /sbin/fsck.btrfs: ...
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159 views

Is btrfs suitable as backup filesystem?

Right now I have a pretty traditional backup filesystem structure on top of ext4. Every time a backup is made, a new folder backup-DATE is created to which files are rsync'ed (with hardlinks made ...
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1answer
33 views

CROSS compilation of BTRFS file system

We are developing Beaglebone black based custom board, We are planing to use eMMC for storage. To decide the file system on the eMMC we want to cross compile Btrfs user space utility, Does anyone know ...
2
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1answer
188 views

btrfs ERROR: error during balancing - No space left on device

My Kubuntu 12.04 system ran out of space on on the root partition and will not boot. The command df -h shows a lot of space available (with only 37% used): /dev/sda2 45G 17G 29G 37% ...
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28 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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4answers
132 views

BTRFS data integrity (CRC32c) and HDD data integrity (sector ECC)

I'm new to BTRFS and I'm trying to understand why BTRFS use CRC32c while HDD already have sector level data integrity ECC. Is it because BTRFS don't relay on media to have data integrity protection? ...
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1answer
80 views

run btrfs balance with cron

Since I run today in a problem with a full disk, which turns out is not unbalanced. Which you can fix with btrfs balance. So my question is: Is there any risk by ruining this by a cron job? (in ...
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1answer
412 views

Is partition table type “loop” a good or bad idea on BTRFS?

I have started to convert my disks to btrfs and following tutorials, most of them created the filesystem directly on the device instead on a partition. The file system is working and stores data but ...
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1answer
48 views

fs synchronization among desktops

I have several workstations (laptops and desktops). I'd like to synchronize files among them such that each one is a mirror of the other. I used to run an NFS server and share files out, but that ...
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126 views

BTRFS Raid1 on SD card and HDD

I have the / partition on a btrfs SD card /dev/mmcblk0p2. /boot is on vfat /dev/mmcblk0p1). It's a Raspberry Pi running Arch Linux and its fstab looks like so: /dev/mmcblk0p2 / btrfs ...
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56 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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1answer
93 views

Why does ZFS large file not instantly like btrfs?

Copying a 1TB disk image on a btrfs partition with cp takes less than a second on my Ubuntu 14.10 amd64 with Linux 3.16.0. Why does it take at least 5 minutes and requires > 1 GB to be read on a ZFS ...
2
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1answer
30 views

Is it possible and how to merge identical files between different snapshots in a btrfs file system?

I regularly use btrfs's snapshot to backup the whole system, but it's redundant to have identical files between different snapshots. Commonly, for example, I took a snapshot of @ as ...
2
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1answer
32 views

How to free up space on non-responsive full btrfs system?

I copied files to a btrfs raid-1, which turned out not to fit. When the drives became full, they also became unresponsive. ls [directory], never finishes. I tried rm ...
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215 views

btrfs balance fails due to enospc error

[taken over from stackoverflow since I figured that was probably the wrong place] I am currently testing btrfs as a possible replacement for my NAS running ZFS. I created 4 devices, 20GB each, and ...
2
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206 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: ...
3
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1answer
882 views

How to install Debian Jessie properly onto multiple devices with BTRFS in mode RAID 1?

As a short introduction I'm going to tell you, what kind of setup I have and what I want to achieve. After that I try to explain my problem. Since this is my first question on U&L I have to ...
3
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0answers
278 views

Which file system (among XFS, BTRFS and EXT4 only) does provide the best data resilience to disk corruption? [closed]

Question: Given these three filesystems: XFS, BTRFS and EXT4, I'm wishing to know which does provide the best data resilience to data corruption in a setup without RAID. And, of course, why? ...
8
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1answer
82 views

Rolling back btrfs subvolume with child subvolumes

Is there a canonical way of rolling back to a subvolume snapshot that has child subvolumes. So for example, this is my btrfs volume layout: ID 257 gen 59802 top level 5 path __active ID 258 gen 59784 ...
4
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1answer
195 views

Simulate bitrot/corrupt files (for BTRFS)

Is it possible to intentionally corrupt a file so that BTRFS will report a checksum error? I want to test a script that's supposed to find file names with checksum errors, but I don't have any corrupt ...
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116 views

How to run SSD trim fstrim on btrfs when mounted multiple subvolumes?

I am using btrfs and have mounted several subvolumes (but not btrfs root). It resides on SSD partition, so I would like to use fstrim. Should I call fstrim on each mountpoint (corresponding with ...
3
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0answers
26 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 ...
5
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1answer
106 views

Why does the mountpoint of my root filesystem change?

When I look at the output of lsblk it will usually show: lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 298.1G 0 disk ├─sda1 8:1 0 1023M 0 part /boot └─sda2 8:2 0 ...
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1answer
949 views

How to make a btrfs snapshot writable?

According to the btrfs Readonly snapshots patch it's possible to "set a snapshot readonly/writable on the fly." So I should be able to turn my readonly snapshot (created with btrfs snapshot -r) ...
2
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1answer
183 views

What privileges are needed to delete a read-only btrfs subvolume?

I want to delegate non-root user to delete read-only subvolumes (snapshots). What exactly capabilities/rights I need to grant, so that he can remove his own read-only snapshots? I've already ...
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1answer
538 views

Docker - Force to Use AUFS Instead of BTRFS

I am having significant problems using Docker on my BTRFS filesystem, and I suspect that is due to a lack of stability with the BTRFS driver. I would rather figure out how to switch the fs driver than ...
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169 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 ...
9
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1answer
248 views

Limit on the number of btrfs snapshots?

I am considering using btrfs on my data drive so that I can use snapper, or something like snapper, to take time based snapshots. I believe this will let me browse old versions of my data. This would ...
1
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1answer
110 views

How reliable is (or will be) btrfs send/receive?

We have at work a 15TB NFS file server using XFS, with a distant clone for backups using rsync, over a moderately slow connection (100Mb ethernet). We are now thinking about using btrfs instead of ...
3
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1answer
84 views

Get device with major number 0 (btrfs subvolume)

When I stat a file on a btrfs subvolume I get a major device number of 0. Is there a reliable way to find the mount point of this device, without knowing in advance it is a btrfs subvolume? e.g. I'd ...
0
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1answer
68 views

btrfs confused about subvolumes

I'm starting out with btrfs on my embedded Linux system. My system currently has a single SD card used for the rfs. What I'd like to do is have a way to snapshot both the system files (currently ...
1
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1answer
289 views

What actually happens when the checksum fails for a file using btrfs?

I'm testing using btrfs on my embedded Linux system. It uses a uSD card for the rfs. This system is remotely deployed so there's no human sysadmin to take care of it. My question is what happens ...
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1answer
54 views

btrfs snapshots without subvolumes?

I'm starting to use btrfs. I want to be able to snapshot certain directories but do not want to create sub-volumes. Is this possible?
2
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1answer
350 views

btrfs on SD card, what does “Btrfs detected SSD devices, enabling SSD mode” mean exactly?

I'm experimenting with using btrfs on my Debian Linux armhf system. The rfs is on a micro SD card. On bootup I get the message "Btrfs detected SSD devices, enabling SSD mode". What features does ...
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2answers
81 views

Shrink btrfs from /dev/sda to /dev/sda1

suppose I have 2 btrfs filesystems: one mounted on /mnt/big spanning across /dev/sda /dev/sdb /dev/sdc /dev/sdd the other mounted on /mnt/small on a single drive: /dev/sde How would I shrink the ...
2
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2answers
227 views

Error when creating BTRFS Filesystem

I'm attempting to install Arch Linux using the btrfs filesystem. I'm at the beginning of the install processes preparing my drive and I'm hitting an issue. Firstly I begin to clear any GTP and MBR ...
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1answer
806 views

How to find data copies btrfs

I have deduplicated my btrfs filesystem with bedup, so now all duplicate files (above a certain size) are "reflink" copies. Is there any way to see, given a filename, what other files are the same ...
3
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2answers
219 views

ext4 to btrfs conversion: If I accidentally lose power to the system during the conversion, will I lose the data?

I want to convert the 3TB 80% full ext4 block device into btrfs and I want to estimate the risks involved in the process. If I accidentally lose power to the system during the conversion, will I ...
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22 views

ext4 to btrfs conversion: Can I pause, reboot the system and then resume the conversion? [duplicate]

I want to convert a rather big ext4 volume into btrfs. How long will the process will take?