Server Fault Stack Exchange
Server Fault Stack Exchange

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

243 questions
11
votes
5 answers

Does btrfs balance also defragment files?

When I run btrfs filesystem balance, does this implicitly defragment files? I could imagine that balance simply reallocates each file extent separately, preserving the existing fragmentation. There is an FAQ entry, 'What does "balance" do?', which…
pauldoo
  • 359
5
votes
2 answers

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
  • 321
5
votes
1 answer

BTRFS checksum cost

BTRFS (or ZFS, which I have no experience of) has checksum functionality "built-in", which seems like a very good feature. My Synology NAS gives me the option of enabling it for any given folder, so it begs the question of: should I enable it for…
Johan Sonesson
  • 151
3
votes
1 answer

Multiple btrfs volumes with different RAID levels on the same devices

I have two disks - one xGB and one (2x)GB. I would like to have one mountpoint from these disks under raid0 and one under raid1, spread over the total available space. Is that possible with btrfs without creating two fixed-size primary partitions on…
Steve
  • 590
3
votes
1 answer

btrfs check shows checksum verify failed even after scrub

Running btrfs check shows several errors like this (13 in total): checksum verify failed on 369098752 wanted 0x0000000000000000000000000000000000000000000000000000000000000000 found…
13xforever
  • 181
2
votes
1 answer

multi-device btrfs with single data mode and disk failure

I had a btrfs partition on a 6 disk array without raid (metadata in raid10, but data in single), and one of the disks just died. So I lost some of my data, ok, I knew that. But two question : Is it possible to know (using metadata I suppose) what…
pums974
  • 31
1
vote
0 answers

Btrfs minimum free space for raid 5 convert

I have a btrfs array of 7 drives that I just finished building. It's currently in "single" mode and I'd like to convert it to raid5 (I understand the risks and the write hole issue). Per the documentation, The way balance operates, it usually…
NStephenH
  • 11
1
vote
1 answer

BTRFS raid with odd number of devices

I used to have RAID10 btrfs setup with 4 disks. Now I added sdf a new disk (its doing the balancing): Total devices 5 FS bytes used 5.73TiB devid 1 size 3.64TiB used 2.78TiB path /dev/sdd devid 2 size 3.64TiB used 2.78TiB path /dev/sdc devid …
langle
  • 11
1
vote
1 answer

Can I mount a BTRFS snapshot of a live filesystem?

I wonder if it is possible to mount one or more snapshots of the same BTRFS filesystem for analytical purposes.
DejanLekic
  • 304
0
votes
0 answers

btrfs mount error "can't read superblock"

I have a synology nas drive in raid6 that had a drive failed. I replaced the drive and had two other drives kicked off the raid after a power failure crashing the storage pool. I was able to move all the drives over to another system and rebuild the…
L. Pinkston
  • 1
0
votes
1 answer

everything deleted out of btrfs volume, but disk usage is still 95%

I have a btrfs volume that formally had a bunch of read-only subvolumes stored on it. I deleted them all. There's no files and no subvolumes, but still no free space. I tried syncing, still no free space. I tried btrfs balance. That does not…
Lawrence D'Anna
  • 287
0
votes
1 answer

To sync before shapshot or not to sync?

There is a Postgres database on BTRFS. I need to make a backup of the database while it is running. Should I do btrfs filesystem sync before the snapshot or btrfs subvolume snapshot does it for me automatically?
Jonas
  • 347
  • 2
  • 10
0
votes
1 answer

BTRFS RAID 0 and Linux reinstallation

In case I add two drives (non-system drives) in RAID 0 using btrfs, what would happen if I need to re-install the operating system, would this RAID 0 be gone and data lost?
Rui Lima
  • 101
-1
votes
1 answer

btrfs formatted partion not mounting from fstab

I have this new mageia 4 setup with some btrfs partitions. My root "/" is on btrfs, working fine. from fstab: UUID=b2b0263e-a04a-4bd7-86d7-d2ec19a90b84 / btrfs relatime 0 0 then I have a different btrfs formatted partition for steam data on…
lievendp
  • 91