B-tree file system, next-generation Linux file system

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How to rsync the / folder properly?

I have a btrfs snapshot of / and I want to rsync it with my current / folder. As form of "rollback" if you want. My question is what folder should I avoid for instance I should use -x option to ...
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15 views

How many volumes should I add in my btrfs?

How much overhead does a single physical partition add to a btrfs volume? ps aux | grep btrfs | wc -l results in 102. I have 4TBx4 in my NAS and 16GB RAM and Core i3 processor. The NAS also hosts a ...
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13 views

How to delete a file in all snapshots on a btrfs system?

I've set up a sophisticated backup scheme with hourly, daily, weekly, monthly backups that take up (thanks to the glory of the btrfs cow-filesystem) almost no extra space on the device. But ...
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22 views
+100

Ubuntu btrfs snapshot cannot mv into /home

I want to be able to take a snapshot and restore it in real time. This works in Fedora and does a live "rollback" : btrfs subvolume snapshot /home /home/snapshot mv /home/snapshot /home But in ...
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1answer
99 views

Why shouldn't I use btrfs for /home?

I'm fairly new to both GNU/Linux and btrfs, but I've decided I want to make my next computer (a desktop with one HDD) use Linux with btrfs as the filesystem. However, I've seen some advice online that ...
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17 views

Files in $HOME losing executable bit

On my laptop running Arch, I have a bunch of git repositories cloned under ~/git. My problem is that from time to time (maybe once in a month or so), all the executable files inside the clones will ...
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10 views

btrfs check: “Couldn't open file system”

When I run btrfs check /dev/sda1, it returns "Couldn't open file system," whether /dev/sda1 is mounted or not. Why? (cf. this)
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1answer
54 views

Finding files with BTRFS Uncorrectable Errors

I have a question concerning unrecoverable errors on a BTRFS file system. Specifically, I've run a BTRFS Scrub recently after experiencing a problem with one of my RAM sticks and it seems to have ...
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26 views

BTRFS filesystem, compression and copy on write

I'm planning about moving from etx4 to BTRFS filesystem on my pc and backup server. I'm very interested in the BTRFS snapshot feature (I have understood it uses the copy on write feature) and the ...
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19 views

Path `/boot/grub' is not readable by GRUB on boot. Installation is impossible. Aborting

Whenever I try updating grub, I get this error: # grub-install /dev/sda Path `/boot/grub' is not readable by GRUB on boot. Installation is impossible. Aborting. and # grub-mkconfig -o ...
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2answers
48 views

What is Btrfs's disk space caching?

I noticed in my syslog that BTRFS reports enabling "disk space caching". What is Btrfs's "disk space caching"?
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12 views

BTRFS & F2FS userspace utilites cross compilation

Is there any weblink/document which describes the steps to cross-compile btrfs & F2fs user space utilities ? Any steps ? special tuning suggestion for arm based board.(AM335x) ?
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9 views

What are btrfs snapshot and subvolume restrictions speaking in terms of read/write access instead of access and data sharing?

The btrfs subvolume manpage tries to explain which type of access is granted to btrfs subvolumes and snapshots. Unfortunately it exclusively uses terms like "access", "use just like a directory" and ...
0
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1answer
71 views

Mirror / backup laptop btrfs drive to sometimes connected external USB disk

I have a laptop with an internal drive using btrfs. There are several subvolumes and snapshots on here. I want a copy of this drive to be made periodically to an external USB disk of approximately the ...
0
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1answer
24 views

how to delete btrfs snapshot?

sudo btrfs subvolume show / outputs / Name: @ uuid: 1f0da442-cdf3-144c-a4ce-f6c06248cfde Parent uuid: - Creation time: 2014-08-16 19:06:51 Object ...
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55 views

Online Drive Replacement: BTRFS with RAID 6

on a testing machine I installed four HDDs and they are configured as RAID6. For a test I removed one of the drives (/dev/sdk) while the volume was mounted and data was written to it. This worked ...
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10 views

btrfs device total usage differs from the sum of each usage

My system lays on a btrfs with 3 disks. btrfs fi show outputs: Label: none uuid: 75a8f1e7-7d79-4a05-8f88-fe02d119bf9f Total devices 3 FS bytes used 14.84GiB devid 1 size 7.74GiB used ...
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1answer
33 views

How come system snapshots are so small in size?

So let’s say a have a file called bob with the size of 10GB in /home. I make a snapshot of /home and delete the original bob file. However I can still access the bob file because I have a snapshot it. ...
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97 views

Mirror / backup laptop btrfs drive to sometimes connected external USB disk

I have a laptop with an internal drive using btrfs. There are several subvolumes and snapshots on here. I want a copy of this drive to be made periodically to an external USB disk of approximately the ...
-1
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1answer
78 views

BTRFS or LVM heterogeneous RAID

I'm entertaining creating a largish (3.5TB+) backup server for my family. I already own enough hardware, and I don't want to buy any more right now. The config I envision look like this: Two 1TB ...
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18 views

How to figure out which partition number an entry in the list has in the Fedora 20 installation routine?

I started the Fedora 20 installation image which I dded onto an USB stick. During the installation I started wondering whether it really is impossible to determine the parition number or UUID of ...
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44 views

It is possible to minimize size of a btrfs sparse file with btrfs filesystem resize and truncate?

Motivation: Assume I have created an oversize sparse file with truncate -s 4T test.img, mounted it over a loop device and put inside 1M files with 100 GB size together. One can assume that btrfs put ...
2
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1answer
266 views

Btrfs raid level for large NAS (8+ 5tb disks)

I'm planning to build a new NAS to store a large amount of media (20tb+). I would like to use btrfs for both the NAS and the backup (might be a separate system, not sure yet) I want to use raid1 or ...
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48 views

BTRFS multiple devices mix raid1 and raid0

Hi Consider the following use case: I have two disks same size (let's say 3TB each). Then create a btrfs filesystem using both devices. Now I want to have two subvolumes "idata" and "ndata". Where ...
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2k views

ext4 vs btrfs performance on SSD array

I am observing something that I cannot explain. I am trying to come up with a good filesystem configuration using HP P420i controller and SSDs. Out of curiosity I have tried BTRFS (still unstable so I ...
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2answers
72 views

Is there something analogue to LVM logical volumes in BTRFS?

I like the way BTRFS does snapshots and subvolumes but it does not feel right to use LVM just because I want my logical volume to be of certain size. Is there something analogue to LVM logical ...
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1answer
65 views

How do I deal with BTRFS raid1 when usb disk device mappings changes?

I created a btrfs raid1 one by using "mkfs.btrfs /dev/sdc1 /dev/sdg1". It worked fine but next time I restarted my pc it seemed like the sdg device became sdf therefor btrfs refused to mount this ...
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1answer
29 views

btrfs won't run from cron

I'm trying to set up a cron job to create a btrfs subvolume snapshot of my root partition. The command works perfectly if I run it from the command line, but nothing happens at the scheduled cron ...
0
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1answer
248 views

How to snapshot a btrfs root file system (snapshot of /)?

I have Fedora 20 and when I installed it I choose to go with btrfs as file system, by many reasons but mainly to have snapshots available. But I can't seem to create a snapshot of /. I can snapshot ...
0
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1answer
283 views

How to monitor BTRFS filesystem raid for errors?

I saw some documentation on a daemon that can execute a program/script for various BTRFS events, but I cannot find it anymore. How can I have a script/program be executed on a drive failure for a ...
2
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1answer
281 views

partitioning and subvol strategy with btrfs

I'm new to btrfs and I'd like some advice on partitioning and subvolume strategy. The system is a light-duty web server, and assume it only has a single disk. With ext filesystems, I've always ...
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22 views

Are re-combined BTRFS incrementals identical to the original?

I have several systems running btrfs, and I'd like to use the btrfs subvolume send/receive features as a backup solution. I want to send daily incrementals to remote as efficiently as possible. That ...
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116 views

Is it possible to convert a btrfs RAID5 to a RAID6 with the same disks without losing data?

How would I convert an existing RAID5 (single parity) btrfs setup to a dual parity RAID6 configuration given enough free available disk space, using the same disks, without swapping out data ? ...
1
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1answer
92 views

RAID 0 or btrfs on two SSDs?

I have two 500 GB SSD's, and I would like to combine the two in some way to have 1 250 GB NTFS partition, and 1 750 GB btrfs or ext4 partition. As far as I see, I have two options: the Intel Rapid ...
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2answers
254 views

Is RAID1 or similar needed for btrfs/ZFS to protect against bit rot?

I'm running a file server using Linux software raid, set up as raid6. As filesystem I've chosen btrfs. However, I'm not using btrfs own raid6 implementation as it's not very stable yet. So basically, ...
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1answer
851 views

How to recover this btrfs error?

I have a btrfs file system that cannot be mounted anymore. I resetted the computer and after boot a Java process crashed, showing a core dump with much btrfs stuff on the stack. After that happened, ...
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1answer
44 views

Is there a way to show RAID details in a similar way to MDADM?

I find mdadm --detail <device> very useful when I need to know what is going on with the device (/proc/mdadm too). Example: /dev/md0: Version : 1.2 Creation Time : Mon Mar 4 ...
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100 views

btrfs does not show drive as missing

I am trying out btrfs and I noticed some funny behaviour: I have two drives in a raid 1 configuration. sudo btrfs fi show Label: none uuid: 52b9c6f6-ce5c-4727-861e-e2fd012e475f Total devices 2 ...
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1answer
822 views

Reasoning behind hosting virtual disk images on BTRFS Filesystem

I have been reading about BTRFS and ZFS for a while and while I do appreciate the benefits of CoW when hosting important files I am currently puzzled by the following dilemma: Given that both ZFS and ...
0
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1answer
683 views

Full BTRFS partition unusable

I have an extremely critical set of circumstances. I installed snapper on my Fedora 20 box. It created around 20 snapshots. My btrfs partition is now full of snapper subvolumes. My partition became ...
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1answer
228 views

Is Btrfs vulnerable to RAID write hole effect?

If not, does it mean that Btrfs in RAID mode is fully resistant to power failure?
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2k views

Can a failed Btrfs drive in RAID-1 be replaced live?

I am trying to decide on a filesystem and would like to know if it is possible to replace a failed drive in btrfs RAID without downtime. Suppose I create a new btrfs filesystem using the command ...
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1answer
39 views

Hierarchical snapshots strange behaviour

I have divided my drive into two btrfs paritions: one is mounted as / (dev/sda1), second one as /home (/dev/sda2). I made my initial snapshot of /home: mkdir -p /home/snapshots/mnt mount -o ...
2
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1answer
538 views

How do I find out the compressed / uncompressed file sizes on btrfs?

I am using btrfs on one of my hard drives. I would like to know the actual file size and the compressed file size on btrfs. I am interested in seeing the compression ratios per file . For example ntfs ...
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0answers
80 views

Btrfs snapshot space and time overhead

Using btrfs-snapshot-rotation, I've setup a system to rotate snapshots so that it always has snapshots of: Each of the the last 24 hours Each of the last 30 days Each of the last 12 months. This ...
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73 views

For raid1, does btrfs check which partitions are on the same device?

I have btrfs on two partitions using btrfs's raid1 mode: /dev/sda3 /dev/sdb3 Now I plan to run btrfs device add /dev/sda2 /dev/sdb2, so I'll have four partitions: /dev/sda2 /dev/sda3 /dev/sdb2 ...
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1answer
1k views

btrfs: HUGE metadata allocated

I have a 256GB SSD disk on which I converted my ext4 root FS to btrfs. I erased the ext4 backup subvolume, enabled compression and defragmented recursively to enable it on all files. btrfs fi df / ...
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1answer
220 views

Does mounting a btrfs subvolume work recursively?

With the following subvolumes on a btrfs filesystem on /dev/sda3: root root/home and the following mount: /dev/sda3 on / Is the /home folder on the root subvolume, or on the root/home subvolume? ...
3
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1answer
283 views

Is it currently stable to use, and boot to, a btrfs RAID 0 on SSDs?

As of the current (3.10+) Linux kernels, is it supported to make a btrfs RAID 0 out of SSDs the root mount and boot to it? This comprises several issues: Does the RAID 0 with SSDs support ...
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1answer
364 views

Can I merge two btrfs without data loss

I have a btrfs device mounted, it is composed of 2 partitions and it is in single mode (the partitions does not have the same size so I can't use raid 0 ). I have another disk formatted in ext4, I ...