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

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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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10 views

What are btrfs generation_errs?

I have a btrfs file system that I've scrubbed a few times and found some errors. If I check the device status I see that I have generation_errs: $ sudo btrfs device stats /dev/nvme0n1p5 ...
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25 views

taking snapshots of a BTRFS volume mounted with nodatacow?

I plan to create two subvolumes on a BTRFS-formatted spinning disk. I plan to mount one of those subvolumes with nodatacow so that I can efficiently store virtual machine images and database files ...
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2answers
24 views

Is there a way to determine compile-time state of a kernel flag from a running system?

I have a running kernel and I'm trying to determine whether it was compiled with support for BTRFS extended attributes. Is there a way to determine a running kernel's compile flags?
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34 views

Resumable transfer for btrfs send

I am planing to backup data via sending btrfs snapshots to an online storage. The storage is mounted as a LUKS encrypted container file on a cifs share. Later transfers will be reasonably fast, but ...
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38 views

Why does my tumbleweed opensuse fstab contain so many btrfs subvol entries?

What is the purpose/reasoning/technical-reason why my opensuse tumbleweed system has so many folders of my filesystem "wrapped" (not sure if that's the right word) as sub volumes on btrfs? Does it ...
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37 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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29 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 ...
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127 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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16 views

List files in unmountable but recoverable BTRFS partition

I have a NAS running Debian with an unmountable BTRFS partition on RAID5. I do not know the exact cause of the probem and Googling the errors from the logs leads no results. Apparently ...
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27 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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59 views

Make tar (or other) archive, with data block-aligned like in original files for better block-level deduplication?

How can one generate a tar file, so the contents of tarred files are block-aligned like in the original files, so one could benefit from block-level deduplication ( ...
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29 views

Max number of subdirectories in btrfs

Is there a maximum limit to the number of subdirectories in a single directory for btrfs like the 64,000 limit in ext4? (see here: ...
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29 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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31 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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1answer
34 views

How to isolate snapshot volumes with btrfs?

If I create a snapshot of root with: btrfs subvolume snapshot -r / /snapshot-$(date +%s) I can then see this snapshot with ls / How do I make snapshots that are isolated from the volume that they ...
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36 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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1answer
69 views

Btrfs+LXC: any way to show even rough estimated free space for quota'ed subvol hosting LXC container?

I'm experimenting with LXC using Btrfs as a backing store. Btrfs allows for easy snapshot/deduplication and is ideal for spinning up several "pseudo-VMs". The problem I'm having is that some of the ...
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2answers
52 views

How to verify a file copy is reflink/CoW?

I'm playing with btrfs, which allows cp --reflink to copy-on-write. Other programs, such as lxc-clone, may use this feature as well. My question is, how to tell if a file is a CoW of another? Like for ...
3
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1answer
135 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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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. ...
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1answer
68 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 ...
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43 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 ...
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1answer
34 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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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 ...
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1answer
32 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 ...
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16 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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2answers
102 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) ...
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12 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 ...
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1answer
158 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 ...
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1answer
39 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 ...
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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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1answer
123 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 ...
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104 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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1answer
93 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 ...
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1answer
131 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 ...
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137 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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48 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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46 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 ...
4
votes
1answer
71 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 ...
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2answers
153 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, ...
2
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1answer
187 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 ...
2
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1answer
303 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 ...
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1answer
47 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 ...
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1answer
316 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 ...
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1answer
315 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 ...
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132 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 ...
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50 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 ...
5
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1answer
126 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 ...
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1answer
386 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 ...