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.

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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 ...
0 votes
0 answers
66 views

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 ...
0 votes
0 answers
25 views

Is it safe to mount same btrfs subvolume multiple times at same time?

I know that it is safe to mount multiple volumes from the same btrfs volume at the same time. But what about the same subvolume? The subvolume would be mounted from the same Linux kernel instance. ...
0 votes
1 answer
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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 ...
38 votes
5 answers
16k views

Does btrfs have an efficient way to compare snapshots?

While diffing mounted snapshots would work, it sounds like it could be horribly slow in many cases. Is there btrfs specific functionality for diffing snapshots? (I was unable to find any in the docs)
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"Can't read superblock" when trying to boot . Failed to mount /dev/mapper/xxxxxxx on real root

I finished setting up my new Arch system about a month ago. Since I had two nvme drives to use for the system I did some research on how I could use both of them to utilize the full capacity of both ...
14 votes
4 answers
17k views

Which filesystems offer snapshot functionality for users to recover data?

I'm working on a project that will teach linux to youth. Knowing they will have a tendency to delete or corrupt items in their home directories we are looking for a good snapshot option. We will not ...
0 votes
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Formula or rule of thumb to estimate filesystem planning with BtrFS snapshots (SLES or similar)

SLES features BtrFS for the root filesystem, combined with automatic ("numbered") snapshots performed before and after updates. If your system fails, you can boot from an older snapshot (...
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BTRFS after multiple power outages bad checksum

After multiple power outages, btrfs have bad checksums, is it possible to recover it? Outages were on Dell R740xd with PERC H730P Adapter looks like the cache was unwritten. now trying to recover in ...
1 vote
1 answer
1k views

Cannot "apt upgrade" due initramfs error - "update-initramfs: failed for /boot/initrd.img-5.15.0-86-generic with 1."

I have a Ubuntu 22.04 VM with CloudInit on a Proxmox Host which worked well, but recently I got often the issue after some time (some days, even after reinstalling) that I can't upgrade packages due ...
1 vote
1 answer
699 views

Enable BTRFS in kernel (running Rocky Linux 9.2)

I am trying to read an encrypted filesystem pulled from a Fedora 38 installation on Rocky Linux 9.2. When I plug the SSD in, it shows the following error: I suppose that this means (1) the default ...
2 votes
1 answer
977 views

how to migrate docker to use a different storage driver?

I have a server running docker with btrfs storage driver. How can I migrate it to use a different storage driver? I would like to use overlay2. I've tried to migrate using the instructions here: stop ...
1 vote
1 answer
446 views

Show quota limit of user's home directory

What I am trying to do is to get quota limit of current system user's home directory, which is btrfs quota-enabled, using the following command: /usr/sbin/btrfs qgroup show-reF ~/ The above command ...
1 vote
1 answer
269 views

Does "btrfs filesystem defrag -c" (compress option) force compression?

BTRFS with compression enabled uses a heuristic not to compress files that are not well compressible. Does compressing existing files with "btrfs filesystem defrag -c" also use the heuristic,...
0 votes
1 answer
345 views

Is it possible to relocate the mount point of a btrfs subvolume within the same root?

I have created a btrfs subvolume in the path of /docker/nc/data. As shown below: $ sudo btrfs subvolume list / ID 256 gen 13908 top level 5 path docker ID 257 gen 13877 top level 256 path docker/nc/...
2 votes
1 answer
292 views

Can I replace a disk in btrfs raid1 without a reboot?

I am trying to understand how btrfs raid1 mode behaves when you take out one disk and put it back (odroid hc4 is an example device) Here is what I have before the test: Label: none uuid: f85fb0ab-...
0 votes
1 answer
68 views

BTRFS partition auto mounts ro

i have my /home/ on a btrfs partition and it appears like after loggingf in to Plasma with my default userm, it becomes mounted ro (rw after boot before login). I booted a USB live system asnd ran ...
0 votes
1 answer
83 views

btrbk not taking hourly snapshots

I have installed btrbk and I would like hourly snapshots to be taken. However, only daily snapshots are done. I wonder what goes wrong. Pleas help me out. Environment: OS: Ubuntu 23.04 64bit / Linux 6....
3 votes
3 answers
1k views

How to shrink btrfs image file used by LXD storage?

I have btrfs image file set as backend for LXD (2.18) but I would like to shrink it's size. What I did: mounted image to loop device losetup /dev/loop1 /home/btrfs.img mounted device to /mnt dir ...
6 votes
4 answers
7k views

Linux KVM Client filesystem (BTRFS?)

in our company we have a lot of kvm clients on multiple server, most of the clients are running ubuntu 16.04 as well as their host systems. The filesystem of choice became EXT4, for clients and hosts....
1 vote
1 answer
260 views

Samba shadow_copy2 and snapshots don't appear in windows

I'm setting up Ubuntu server with Samba. The file system is BTRFS and I can't seem to get Windows to see the previous versions from the snapshots. My smb.conf has this for the share: [Backup] path ...
5 votes
1 answer
764 views

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 ...
0 votes
0 answers
64 views

BTRFS filled to 100% and does not mount anymore

I have a 50 TB BTRFS filesystem on a hardware RAID array in an HPC cluster I manage. Users have filled up this partition to 100% and complained about I/O errors while reading old files. The filesystem ...
0 votes
0 answers
26 views

Bootprocess stops after detaching raid member

I run following Setup in my Testlabor before migrating into production: Dm-crypt/luks Raid1 / btrfs EFI dracut / fedora Server GRUB2 Systemd I simulated a drive failure (the one without boot partition)...
1 vote
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341 views

How to run script after partitioning step in a automated debian install (preseed.cfg)?

I am trying to configure an automated Debian 12 installation using the BTRFS filesytem, which should support timeshift for snapshots. So far, I have a complete preseed.cfg, integrated into the Debian ...
1 vote
1 answer
415 views

AWS EC2 EBS: btrfs partition and FS automatically resized by just increasing the EBS volume size?

I had to expand the size of an EC2 EBS root volume that uses btrfs (Fedora 38 Server), so I did the following: Stopped the EC2 instance Expanded the EBS volume via the EC2 console Started the EC2 ...
3 votes
1 answer
136 views

Pooled storage with varying redundancy per file system

I have some files that I want stored mirrored. I have some files that I only need single copies (i.e. scratch data, easily regenerated data, etc). And I have some files that are so critical, I want it ...
0 votes
1 answer
198 views

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 ...
11 votes
5 answers
16k views

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 ...
1 vote
0 answers
322 views

RAID + LUKS + LVM + BCACHE + BTRFS

I want build new structure for my data store (NAS - Ubuntu). Data storage will be 4TB at first. Then up to 8TB. My old structure is simple: RAID 1 -> LUKS -> FS I need some wishes to new ...
3 votes
3 answers
4k views

How to increase speed of RAID 5 with mdadm + luks + lvm

I think I am kinda lost with my current server setup. It is an HP Proliant dl160 gen 6, and I put 4 spinning disks with a setup that has mdmadm + luks + lvm and on top of it btrfs (maybe I went too ...
1 vote
1 answer
1k views

Growing a RAID-10 on Synology NAS?

I was hoping to add two additional disks to my Synology NAS. Currently it is configured as a four disk RAID-10, no SHR, BTRFS, single volume system. Unfortunately extending a RAID-10 is not possible ...
0 votes
1 answer
685 views

How to combine an SSD with two HDDs in a RAID1-ish hybrid setup?

Coming from Linux SSD as HDD cache, I'd like to set up an SSD (or rather a partition thereon) as cache for basically a RAID1 of two HDDs. But since the data might remain cached on the SSD for while, I ...
4 votes
3 answers
11k views

Linux-on-Linux KVM: Which filesystem should I use for guest and host?

I'm in the process on playing around with KVM and setting up a linux on a linux-server, so I can reboot the (guest)server encrypt the rootFS of the guest without having to do initramfs-tricks to get ...
0 votes
1 answer
392 views

Setting up resilient single drive NVMe storage for LUKS encryption

I would like to set up resilient encrypted storage with single NVMe drive for my laptop and its (encrypted) backup (with SATA housing and SSD drive). This is what I have at the moment: SSD -> GPT ...
9 votes
2 answers
1k views

Can Btrfs use SSD for metadata and leave bulk data on HDD?

is it possible for Btrfs to use SSD for metadata only & leave bulk data on less costly storage such as HDD? I refered to this page Using_Btrfs_with_Multiple_Devices and can not find a solution. ...
1 vote
0 answers
415 views

BTRFS error (device sda1): couldn't find block (456420491264) (level 1) in tree (7) with key (5764 84 3725675564) during balance

I have a 2 TB btrfs drive that is pretty full. While running btrfs balance start -musage=90 I got this error: BTRFS error (device sda1): couldn't find block (456420491264) (level 1) in tree (7) with ...
0 votes
0 answers
646 views

Why is mounted nas showing 0 inodes on users partition?

I am using a NetGear ReadyNAS machine as a NAS for our server. The server is a linux CentOS 6.6. The server is run using Rocks cluster, with all our users' home directories located on the NAS. My ...
0 votes
1 answer
949 views

What capabilities do you lose when turning off COW on a qcow2 file?

I run a small internal cloud utilizing 3 redundant, live migration capable Ubuntu/Qemu/KVM hosts with ~30 mixed OS VMs. The Pool volumes are BTRFS and before any of you give me crap about it: this is ...
2 votes
1 answer
1k views

btrfs - ERROR: Could not destroy subvolume/snapshot: Operation not permitted

We use btrfs extensively for its wonderful snapshotting capabilities. But recently, and on only one system, while purging old snapshots, I began to receive the following error: btrfs subvolume delete ...
0 votes
0 answers
164 views

Shrink one of the disks in a multi device BTRFS filesystem

My root partition is running out of space and I have no other SATA slots. I have a BTRFS raid0 and I would like to shrink one of the partitions I used for the BTRFS-raid0 and add it to the root ...
6 votes
3 answers
10k views

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 ...
1 vote
1 answer
3k views

Btrfs check repair give device busy. How to see what it keeps busy?

I am in a chicken-egg situation for my secondary harddrive (non boot): My BTRFS mount has gone readonly because no space left. btrfs filesystem resize only works on mounted volumes. I needed to ...
3 votes
1 answer
3k views

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 ...
0 votes
0 answers
938 views

Restore disk with btrfs

I need an assistance with restoring HDD where was BTRFS after I tried to install Windows on SSD within the same PC. So, my PC has 3 disks: SSD with Fedora under BTRFS - /dev/sda{x} SSD without any FS ...
0 votes
0 answers
985 views

How do I mount a BTRFS filesystem where both devices have the CHANGING_FSID flag and one devices has journal errors?

I have a RAID-1 BTRFS setup with two 8 TB hard drives. Due to unclean reboots, I cannot mount them anymore, even with recovery flags: rockpro64:~:# mount -t btrfs -o rootflags=recovery,nospace_cache /...
2 votes
1 answer
2k views

Mount command hanging after attaching EBS volumes on AWS

I'm creating four volumes from four EBS snapshots on AWS. The four volumes make up one BTRFS multi-device drive. The drives have no partition tables, i.e I've ran mkfs.btrfs /dev/xvdf /dev/xvdg etc. ...
0 votes
1 answer
119 views

Do BTRFS self-healing mechanisms apply when a folder of the host with BTRFS enabled storage is remotely mounted by a different host?

the file system BTRFS comes with some useful features regarding data consistency/error detection and correction (let's call them self healing mechanisms). Given the following situation, will these ...
1 vote
0 answers
145 views

What can make btrfs device replace fail silently?

In a performance-critical system, we run Btrfs RAID0. We have three devices relevant to this question: /dev/sda2, an SSD that is too small and slow, and limits the size and overall performance of the ...
43 votes
5 answers
72k views

Ext4 vs. XFS vs. Btrfs vs. ZFS for NAS [closed]

My use case: I have Ubuntu Server 18.04 installed on an M.2 SSD. I have a 4TB HDD I want to add as storage. Since it's mostly for large media files and backups, it won't be written to very often. ...

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