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Questions tagged [btrfs]

btrfs is a B-tree based, copy-on-write filesystem for Linux. It's main features include snapshots, checksumming of data and filesystem level RAID support. It's similar to ZFS.

Btrfs tag should be used with all questions referring to usage of features specific to this filesystem:

  • defragmentation
  • resizing and addition and removal of block devices
  • it's RAID implementation
  • snapshot creation and usage

Also see:
for a similar copy-on-write filesystem.
http://btrfs.wiki.kernel.org for detailed information about the filesystem

218 questions
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How to btrfs check a root partition

I'm sure the reason I'm having a brain fart is because it's late, but how can I go about performing a btrfs check on the root partition? The device needs to be unmounted, which can't happen because it's the root partition... Thanks
Dave
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rsnapshot vs zfs / btrfs snapshots

Currently I'm using rsnapshot to implement a daily / weekly / monthly backup scheme on an external disk. Lately I've been reading alot about copy-on-write file systems like zfs and btrfs. I quite like the ability to store snapshots to go back in…
BayerSe
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How do I get the size of a btrfs subvolume (compressed vs. uncompressed)

Is there a command to get the on-disk size of a btrfs subvolume? The file system was mounted with -o compressed and the subvolume contains a lot of files that should compress rather well. I could use du on the root folder but then I will only get…
Perseids
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What are my prospects of recovering old version of file on BTRFS

I've accidentally overwritten an important file on BTRFS. Knowing that this filesystem is COW, it should be in theory possible to recover an old version of the file. Unfortunately googling didn't reveal relevant information. Can someone please…
Adam Ryczkowski
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Should I disable btrfs CoW for /var/lib/docker?

I saw that it is not a good idea to use btrfs CoW functionality for big files, such as data directories of a PostgreSQL database. Since I use docker for databases, I now ask myself, if I should disable CoW for the whole /var/lib/docker directory.…
Ethan Leroy
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Btrfs: Remove a large file takes long

I'm running a synology nas DS1817+ with DSM 6.2.2-24922 with a RAID5 volume formatted with BTRFS. Deleting a large file either with DSM FileStation or directly in an ssh session with "rm filename" takes a long time. bash-4.3# ls -al total…
Klaus
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Linux no modify time (nomtime)

Is there a way to disable the mtime of an filesystem? There is an Filesystem independend noatime Option, but no "nomtime". Also in the Filesystem specific documentation for ext4 and/or btrfs i couldn't find this. Does this exist?
白川 マセル
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btrfs increase raid capacity by replacing disks (and not adding disks!)

I'm very excited about the new features of btrfs and would like to start tesing it. Before I get started, I would like to ask if btrfs supports increasing raid capacity by replacing disks by bigger ones (and not adding additional disks). Example: A…
Chris
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Is this btrfs snapshot removal performance normal?

I have several boxes running Debian 8, dovecot and btrfs. I'm using btrfs snapshots for short term backup. For this purpose I keep 14 snapshots of the mail subvolume. Performance is OK until it comes to snapshot removal: as soon as btrfs-cleaner…
tim
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btrfs Integrity and Stress Testing

A DevOps colleague is recommending that we begin transitioning our production environment to using btrfs. We have primarily ext4 filesystems, though some low-usage servers using ZFS (on Linux). As one of the decision-makers, and as one responsible…
Joe
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Btrfs vs ext4 -- Where's the safety break-even point?

Btrfs is still in heavy development and still considered "unstable" by Chris Mason, and many important features are still being added, but the dire warnings of data loss are calamity are long since gone, and it has already become the default…
tylerl
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How to create btrfs RAID-1 filesystem (assertion error in mkfs.btrfs)?

I tried to make a btrfs RAID-1 filesystem in "degraded mode" by following the btrfs UseCases instructions but hit a fatal assertion error. Why is this failing, and is there any workaround? The instructions I followed are…
amcnabb
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BTrFS crashhhh?

I create a new BTrFS raid10 file system using two 250GB drives and the second partition on a third 80GB drive. I create a subvol and snapshot. I mount the snapshot and start copying 8GB of data to it. It gets to around 1GB and the Desktop disappears…
bumbling fool
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How can I format a BTRFS Raid 1 mount?

I'm using a fairly vanilla Ubuntu 10.04 server installation, and I'm experimenting with BTRFS. How can I create a BTRFS RAID1 mount? I've got two (2) 1Gig drives that I popped in the server and after running the following commands, it appears I've…
Jamie
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How to cancel btrfs defragmentation

How can I cancel a btrfs defragmentation? With btrfs fi balance / you can use btrfs balance cancel /. I can find no option for defragmentation. How can I safely cancel?
user133987
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