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

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1answer
11 views

BTRFS, RAID5 and the minimum number of drives required

It's been my understanding that in order to have a RAID5 setup, one would need to incorporate a minimum of three drives. Basically (and probably poor paraphrasing) two blocks of data and a block of ...
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0answers
5 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. ...
1
vote
2answers
27 views

resolve bind mounts with a shell tool/script

currently i have a setup with two hardrives, one with xfs, the other one with btrfs on it. The root fs is mounted on the xfs, and the btrfs under /data. For verious reasons, the directory /var/www on ...
2
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0answers
11 views

Btrfs: available space not used after migrating from RAID1 to RAID6

I had 8 2TB disks running in a RAID1 setup but it started to get full so I converted it to a RAID6. However, it seems I can't use the space I've gained by switching to RAID6. My filesystem is pretty ...
4
votes
1answer
14 views

cannot reduce the size of my Btrfs partition

I need to free up 4T on my LVM which is mainly taken by a Btrfs filesystem mounted on /data. I did: # btrfs fi resize -h btrfs filesystem resize: too few arguments usage: btrfs filesystem resize ...
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0answers
16 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 ...
0
votes
1answer
20 views

How to safely delete a regular directory that contains several btrfs snapshots inside it?

I have a regular directory than contains directly underneath it several btrfs snapshots. Is it safe to do an rm -rf on the parent directory, or do I need to first do a btrfs subvolume delete SUBVOL on ...
3
votes
1answer
40 views

How to find out if a file on btrfs is copy-on-write?

I know that cp has a --reflink option to control full copies vs. copy-on-write "copies". On btrfs, can I use ls (or some other command) to find out whether a file shares (in a copy-on-write senses) ...
4
votes
1answer
176 views

How do I view the btrfs checksum of a file?

Btrfs calculates a crc32c checksum for each file. Is there a way I can view what checksum is stored (as opposed to just reading the file and recalculating it)?
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vote
0answers
11 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. ...
0
votes
0answers
11 views

btrfs shrinked after failed balance

I have a btrfs on a 2TB disk. According to btrfs fi show, less than half of the space is used: Label: 'photo' uuid: cccecc10-da2c-4fd6-ae38-31d160dfb6df Total devices 1 FS bytes used 753.21GiB ...
1
vote
1answer
25 views

How do I mount my problematic (btrfs?) disc?

I have an old harddrive that I want to check the contents of. I think it may previously have been part of a BTRFS raid1 setup, now replaced by a larger drive. When I connect it with a USB-adapter, I ...
3
votes
1answer
235 views

How to get error detection and correction on a single hard drive on linux (with btrfs or other methods)

One of the cool things about btrfs on linux is that it can correct bit rot if it has redundant data because of its per-block checksumming. I can get redundant data by setting up a raid1 with two ...
0
votes
1answer
54 views

Does it make sense to put btrfs on lvm?

This is OpenSUSE Leap 42. I have a computer with 2x 500 GB SATA HDD drives and to speed it up I put in a small 30GB SSD drive for the system. During installation HDDs were disconnected as they ...
3
votes
0answers
49 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 ...
0
votes
1answer
156 views

Filesystem is reporting a write error on a specific sector even after the partition is moved further

I am facing the following problem: btrfs reports write errors for sector 128 on device /dev/sdd: sd 6:0:0:0: [sdd] Invalid command failure sd 6:0:0:0: [sdd] Result: hostbyte=DID_OK ...
2
votes
4answers
2k views

How are filesystem snapshots different from simply making a copy of the files?

by doing this, # btrfs subvolume snapshot /mnt/1 /mnt/1/snapshot # tree /mnt/1 /mnt/1 ├── a ├── snapshot │ ├── a │ └── subv └── subv └── b 3 directories, 3 files We can create snapshot ...
0
votes
1answer
31 views

I'm unable to mount a btrfs partition

I had a raid 5 array of 3 disks using btrfs (raid provided by btrfs) one of the disks was damaged and I replaced the disk via: btrfs device add /dev/sdc /media/raid/ btrfs device delete missing ...
4
votes
1answer
3k views

Clear unused space with zeros (btrfs)

How to clear unused space with zeros ? (I am asking for tool for btrfs filesystem) I'm looking for something smarter than cat /dev/zero > /mnt/X/big_zero ; sync; rm /mnt/X/big_zero Like ...
3
votes
1answer
39 views

What is the proper way to unlock a root filesystem spanning two LUKS devices by only entering the password once, using systemd?

I have been having a lot of issues getting an encrypted multi-disk root filesystem to boot up reliably under systemd on Debian Jessie while only having to enter the password once. Previously I've ...
5
votes
0answers
77 views

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 ...
3
votes
1answer
56 views

Can I get SSD rw performance while keeing data security if I combine SSD & HDD in btrfs RAID1

I have 2 storage devices; classical slow HDD (750GB, /dev/sda) and faster SSD (128GB, /dev/sdb). Currently I have installed Ubuntu & Mint on same btrfs partition on SSD (/dev/sdb5). My btrfs pool ...
2
votes
0answers
49 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 | ...
9
votes
1answer
84 views

How to duplicate a file without copying its data with btrfs?

I have no experience with btrfs, but it's advertised to be able to de-duplicate files. In my application, I'd need to duplicate whole directory trees. From what I learned, btrfs only de-duplicates ...
1
vote
1answer
104 views

Configure Snapper/snapshots on Fedora 23

I am getting an error while trying to configure snapper on F23. My root partition is btrfs, and I have installed the snapper package. The error is occurring when I initially try to create the default ...
0
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0answers
55 views

btrfs balance memory requirements?

I'm trying to rebalance data on my btrfs filesystem to free up some (a lot) of disk space. However, my machine consistently keeps OOMing itself into death. Currently I'm assigning 1.5 GB of RAM but ...
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vote
0answers
42 views

How many btrfs snapshots is too many? [duplicate]

I've been doing daily snapshots on a btrfs subvolume for nearly 3 years, resulting in over a thousand snapshots. I am experiencing occasional small stalls (a few seconds) in basic filesystem ...
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vote
0answers
21 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 ...
2
votes
2answers
75 views

Btrfs subvolume UUID clash

Two file systems with the same UUID on the same computer are problematic, eg. it could lead to data corruption, especially if both are mounted at the same time (like the BTRFS wiki says too). So, ...
6
votes
3answers
2k views

Modifying a BTRFS filesystem UUID

I've made backups of my BTRFS filesystem using Clonezilla, and have restored one of those backups to a file named 2013-11-29.sda3.img. I need to get some files out of this backup, but there's a ...
4
votes
2answers
3k views

How to delete btrfs subvolumes with <FS_TREE> in their name

I have a bunch of btrfs snapshots like so: 20:17:37 [root@galaxy /]$ btrfs subvolume list -a / |grep apt ID 271 gen 348 top level 5 path <FS_TREE>/@apt-snapshot-2013-04-17_21:44:30 ID 272 gen ...
5
votes
3answers
4k views

Is there a way to monitor progress of a btrfs rebalance?

I'm replacing a failed harddrive in a mirrored btrfs. btrfs device delete missing /[mountpoint] is taking very long, so I assume that it's actually rebalancing data across to the replacement drive. ...
5
votes
2answers
140 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 ...
12
votes
4answers
10k views

How to get rid of the “scanning for btrfs file systems” at start-up?

After upgrading from Ubuntu 12.04 to Ubuntu 12.10, I get a message "scanning for btrfs file systems" at starting-up. I don't have any BTRFS filesystem. It delays the booting for about 15 seconds. How ...
17
votes
3answers
5k views

What are the advantages of Btrfs for end users?

Btrfs has begun to gain some momentum in replacing ext4 as the default filesystem of choice for a few distributions such as Fedora Core 16. It is experimentally available in a number of other ...
0
votes
1answer
67 views

How to know perfect filesystem parameters for flash drive format

I have a flash drive and using btrfs on it with default parameters. And now I'm going to slightly improve read/write speed. I see that "play the game" with page and sector size can helps me. But ...
1
vote
1answer
76 views

btrfs - snapshot of a parent subvolume excludes child subvolumes?

Let's say I want to exclude ever-changing logfiles from backups. Parent subvolume / Child subvolume /log I snapshot /. Looking at the snapshot, /.snapshots/today/log will be empty, correct? This is ...
2
votes
1answer
175 views

Btrfs/ZFS Network Replication

Is it possible to replicate a ZFS or Btrfs raid volume in real-time (or as close to as possible, network specs aside) over a network? ZFF and Btrfs are ideal because of their CoW properties. I'm ...
2
votes
1answer
111 views

How to fix BTRFS superblock error after resize/shrink (BTRFS: couldn't get super buffer head for bytenr 274877906944)

BTRFS RAID1 array with 2 500 GB hdds, no errors. This is the root filesystem, so there are 3 partitions on each drive: 1 = /boot (ext4), 2 = / (btrfs), 3 (swap) /boot is ext4 because upgrading the ...
2
votes
1answer
29 views

Can move but can't remove empty /home directory (root, no attr, RW filesystem, not mount point, not busy)

I can move it but rmdir and rm -rf fail even as root (failed to remove '/home': Operation not permitted). lsattr is all ----------. Whenever I mv /home /home.bakN I get directories that are also ...
1
vote
1answer
158 views

Does this bug indicate an error in my btrfs filesystem of simply a bug in the 4.2.0-RC5 kernel?

I'm not sure this is the right place to ask this... I have been running a pre-release kernel (4.2.0-rc5) and yesterday had a possible disk error on my 6-disk raid-1 btrfs filesysystem. While trying ...
3
votes
4answers
2k views

How to remove an empty directory (btrfs filesystem)?

I'm using the experimental btrfs filesystem. My directory looks like this: ls -la empytfolder total 4 drwxr-xr-x 1 root root 0 19. Mär 14:00 . drwxr-xr-x 1 root root 298 19. Mär 13:59 .. I ...
2
votes
1answer
330 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 ...
5
votes
1answer
88 views

How do I 'upgrade' existing BTRFs to be fully redundant

How would I convert an existing BTRFs pool, within Debian Jessie (4.2 Kernel) that I created with... sudo mkfs.btrfs /dev/sdb /dev/sdc /dev/sdd ...into being fully redundant, or as redundant as it ...
3
votes
2answers
434 views

How to repair a BTRFS block?

For some unknown reasons, my BTRFS filesystem is corrupted. dmesg prints BTRFS critical (device sda2): corrupt leaf, slot offset bad: block=43231330304,root=1, slot=47 (more than 1000x in the dmesg ...
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vote
0answers
34 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 ...
4
votes
1answer
218 views

Can `btrfs scrub` remember the bad blocks/sectors?

I have a USB thumb drive formatted in btrfs format. But I found if I copy a 1 GB file onto this disk, the file is corrupted. And btrfs scrub reports there're many uncorrectable errors. But if I keep ...
3
votes
0answers
119 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 ...
2
votes
1answer
31 views

Secure deletion on BTRFS in LVM

I have a BTRFS filesystem in an LVM logical volume, which exists inside of a LUKS disk. For reference's sake, let's call the LV lvm-root, and the LUKS disk crypt-root, and the BTRFS filesystem ...
5
votes
2answers
1k views

btrfs and the discard mount option on an ssd

I can't seem to find an answer to this so I thought I would ask here: In /etc/fstab and when using the mount command in ext4 you would add the option discard to activate TRIM on an SSD. Similarly ...