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

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2
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39 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 ...
4
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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
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0answers
12 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 ...
0
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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
47 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 ( ...
2
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0answers
22 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
41 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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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
91 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
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0answers
54 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 ...
1
vote
1answer
951 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 ...
5
votes
1answer
894 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
27 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: ...
1
vote
2answers
123 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
306 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 ...
2
votes
1answer
57 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
25 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
22 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
268 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 ...
1
vote
1answer
24 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
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0answers
25 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
405 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
56 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
102 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
12 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
41 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
24 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
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0answers
17 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
28 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
212 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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0answers
15 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
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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
38 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
104 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
58 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 ...
0
votes
1answer
98 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
62 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
113 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
79 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
97 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 | ...
10
votes
1answer
120 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 ...
2
votes
1answer
152 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
votes
0answers
125 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
46 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 ...
1
vote
0answers
42 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
131 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 ...
5
votes
2answers
4k 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
5k 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. ...