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

learn more… | top users | synonyms

1
vote
0answers
18 views

IO Error when trying to create a Btrfs snapshot

In Fedora 23, my / partition is formatted as Btrfs: /dev/nvme0n1p4 / btrfs rw,seclabel,relatime,ssd,space_cache,subvolid=257,subvol=/root 0 0 Full output: $ sudo cat /proc/mounts sysfs /sys sysfs ...
1
vote
1answer
53 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 [/dev/...
0
votes
0answers
26 views

Does changing your OS (fedora>OpenSuse) or FS (ext4>btrfs) “break” rsync?

I am using a rather simple script to do incremental backups of my laptop to my external HDD's, where the core line is probably the following: rsync -arbuv --delete --progress -exclude-from=/backup-...
2
votes
0answers
35 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 volume,...
1
vote
1answer
1k views

How do you mount a specific btrfs subvolume?

Suppose I start with a non-btrfs system and then add a secondary drive that I format as btrfs. How would I mount /var/log on a subvolume of the new drive instead of on the original drive? Is this even ...
4
votes
2answers
552 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?
20
votes
3answers
6k 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 ...
4
votes
2answers
377 views

How to check (simulate), how much space will be freed after I remove a btrfs subvolume?

The question is not trivial. BTRFS is COW file system and one object stored on hard disk can be referenced by many files. I use BTRFS snapshots as a part of a backup solution on my production server....
6
votes
1answer
4k 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 ...
1
vote
0answers
37 views

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 ...
0
votes
1answer
32 views

Verify file permissions

I did a fresh installation of OpenSUSE and copied all my files from the old home directory. The user and group names hadn't changed, and all the files seem to have proper permissions. However, I ran ...
0
votes
1answer
56 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 ...
7
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 hitch....
0
votes
1answer
51 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 ...
4
votes
2answers
27 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?
3
votes
1answer
60 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 ...
0
votes
0answers
39 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 ...
4
votes
0answers
168 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 ...
0
votes
2answers
1k views

Unknown btrfs error, partition won't mount

a day or so ago my btrfs partition just stopped working, which means i can't mount it anymore which is why my Fedora Linux doesn't boot anymore. I don't really have much information, but Gparted ...
6
votes
1answer
65 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 ( http://unix.stackexchange.com/a/...
2
votes
0answers
30 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 ...
2
votes
2answers
62 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
votes
2answers
2k 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 ...
4
votes
2answers
123 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) ...
2
votes
0answers
58 views

btrfs device add: different mount options than for seed?

I have a btrfs seed device, created with mixed data+metadata (mkfs.btrfs --mixed), and also --metadata single. This device is read-only. When doing btrfs device add /dev/sdc1 /mnt, is it possible to ...
5
votes
1answer
1k views

How to replace a device in BTRFS RAID-1 filesystem?

I have a BTRFS RAID-1 filesystem with 2 legs. One disk needs to be replaced because of re-occuring read errors. Thus, the plan is: add a 3rd leg -> result should be: 3 way mirror remove the faulty ...
0
votes
1answer
32 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: http://stackoverflow.com/questions/22775011/what-is-the-maximum-...
1
vote
2answers
129 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 ...
3
votes
1answer
359 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 disks....
2
votes
1answer
88 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 ...
0
votes
0answers
31 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 ...
1
vote
0answers
41 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 ...
0
votes
1answer
344 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 driverbyte=...
1
vote
1answer
35 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 ...
2
votes
0answers
38 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 ...
0
votes
1answer
465 views

Mount BTRFS on Android (usb OTG)

I am using btrFS as a filesystem for my external harddrive. I'd like to use it under Android. Is there any painless way to do so?
2
votes
1answer
80 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 ...
3
votes
1answer
159 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 ...
0
votes
0answers
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. Currently,...
1
vote
2answers
46 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 ...
4
votes
1answer
55 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 [...
0
votes
0answers
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 ...
0
votes
1answer
33 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 ...
4
votes
1answer
237 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)?
1
vote
0answers
18 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
13 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
45 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 ...
0
votes
1answer
382 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
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 /...
2
votes
4answers
3k 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 ...