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I know, questions like this have been asked before, but I'd like to get some up to date experiences.. From what I've read in various discussions, BTRFS seems like it's relatively stable, but once in a lifetime, with some kind of an upgrade it breaks (don't know how old this info is...). I'm sure, many of you are using BTRFS right now and I'd like to switch to it too, I'd just like to know if YOU consider it stable, had any problems with it, and, well, would you trust it to handle your.... let's say semester project?

TrailRider
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IcyIcyIce
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    What you want is real time(or current) experiences, not opinions. Opinion questions are off topic here. That choice of words may get the question closed as off topic..... I took the liberty of editing it to avoid that. I had to guess at the last typo, I assumed that you wanted to say semester project, if I'm wrong feel free to fix. Interesting question BTW. I had wondered the same thing myself.... – TrailRider Jun 15 '15 at 23:57
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    Thank you for correcting my grammar ;) I hope someone actually using BTRFS will share his experiences soon :) – IcyIcyIce Jun 16 '15 at 00:01
  • I use it for my home partitions. But I also keep my stuff under version control, pushed to a server, with another copy on another system. In the ~3 years I have been using btrfs, I have only had one failure with it, and I'm not entirely convinced it was btrfs at fault (disk starting to fail and sudden power loss - not a good combo). – muru Jun 17 '15 at 21:23

4 Answers4

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I use btrfs for years now and there are situations in which I can not recommend using it. When losing power or shutting down unctrollably, the risk of irreparable damage is high. When the hard disk is operated in nearly full state, sporadic malfunctions may happen and the displayed free space and the usable space may differ strongly. When juggling with big amounts of snapshots, there are rare situations in which data gets inaccessible. Some mechanisms as the deduplication, filesystem repair and scrubbing are systematcally broken.

All that does not appear too good after so many years of development, and I do not have the impression that the situation will improve. btrfs can be used for special purposes, but under no circumstances I would entrust critical data to it.

Klaus-J. Wolf
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  • Could you elaborate on why and how you believe that "mechanisms as the deduplication, filesystem repair and scrubbing are systematcally broken"? Deduplication isn't even an official part of the toolset yet (but the functionality is there). A scrub will also try to repair damage (if there's some redundancy like RAID-6). So what led you to believe that any of this is broken? – basic6 Feb 17 '16 at 14:08
  • The CTO of my company insisted on using BTRFS on a CentOS 6 system in his office that has no uninterruptable power supply (UPS).

    Aside from the questionable situation of running on a 2.6 kernel, running on a system that periodically gets power glitched seems ill advised.

    We've lost data enough times that I am lobbying to pull that system from his office and rebuild it with ext4 (or maybe XFS).

    None of our other, mostly CentOS, production systems have had anywhere near the failure rate of this one.

     – lcbrevard Mar 08 '16 at 17:35
  • @lcbrevard - Running btrfs on such an old kernel in 2016 sounds like a very bad idea, as btrfs itself would surely be an old version too (unlikely that latest btrfs is backported to CentOS/RHEL 6). – RichVel Apr 17 '16 at 07:42
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On the BTRFS Wiki you can find companies that are using it in production or testing it in production so out of the development/testing/staging stages.

So you can use it for your semester project as long as you don't forget to make back-ups!

(But you are making back-ups already, aren't you?)

Community
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Fabby
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  • As you're a reputation 6 user: If this answer helped you, don't forget to click the grey ☑ at the left of this text, which means Yes, this answer is valid! ;-) – Fabby Jun 16 '15 at 00:03
  • Well... I'm worried about the face, which I've read somewhere and I really hope it's old and fixed, which says that after kernel update sometimes the "structure" of btrfs changes a bit (hope it was only during the first stages of development), so my question would be: This is not happening anymore, is it? – IcyIcyIce Jun 16 '15 at 00:23
  • That would be another question. Your original question has been answered. Please don't forget to tick the little grey ☑ at the left of this text, turning it to a beautiful green. :-) – Fabby Jun 16 '15 at 08:29
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    Oh yeah I forgot the tick. Thank you for answering – IcyIcyIce Jun 16 '15 at 09:36
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I'm using it on a pretty small SSD. In general it works quite well and I'll keep it, but wouldn't recommend it to an inexperienced user. However, maybe due to the limited space, I have the impression that it slows my system down a bit (compared to ext4). But the main downside is the need for balancing, which must be done regularly if you don't want to end up with a broken system (that you can recover, but still...). While the balancing is running, the computer is noticeably slower. Greatest advantage (in particular when e.g. writing a thesis as I currently do) are the snapshot capabilities. I use snapper for hourly backups, such that I can recover from recent mistakes of my own. Of course that doesn't replace external backups.

To summarize, if you like trying out new stuff and aren't afraid of small difficulties, you should try it. Do backups, of course, although l haven't experienced any data loss in the last few months since I started using it.

Edit: This is the blog post l followed to recover my system after I had forgotten to balance it often enough.

Edit 2: Snapper is a tool from SuSE to manage BTRFS snapshots. The version from the Ubuntu repository has no GUI, but the command line interface is sufficient.

Edit 3: answering the comment to another answer: I started using BTRFS while 15.04 was beta, hence there has been a lot of kernel updates. I haven't noticed any problems with them.

Edit 4: as pointed out in the comments, the general speed issue probably occurred when the disk got too full. Balancing was always slow, though.

luckyrumo
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    You said, that maybe due to the limited space it's running slower. That can be quite true, because btrfs needs a lot of space because it's a COW system, the "theory" says, you shouldn't push it more then to 80-90% usage. And as for being a "newbie" :D , I have used ZFS on solaris for quite a while, I just couldn't get myself to trust BTRFS instantly, wanted to hear some opinions/experiences and all the forums seemed a bit outdated to me... Anyways, thank you for your reply :) – IcyIcyIce Jun 16 '15 at 01:57
  • Thank you for pointing out the 90% issue. I was already wondering if the slowdown had started after I had added some holiday photos, but now I will certainly move them elsewhere :-) – luckyrumo Jun 16 '15 at 06:47
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    just make some research to understand how is it working, in my opinion 90% isn't still that bad, until you start making big operations with the disk. But with ZFS and BTRFS there's the golden rule - more space = more speed. (or at least less space less speed after some point...) – IcyIcyIce Jun 16 '15 at 06:52
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    If you need version control of your thesis, you should use a version control system (git, for example). Then you can, for example, tar the whole repository and email, or share via the net. Btrfs locks you in here. – not-a-user Nov 26 '15 at 08:04
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I used it on my personal laptop and desktop at work on SSD for the last few years. So far I hadn't experienced any problems or data loss, but then again this is not a server type of workload.

Disk format is stable enough for me during the period I used it, I hadn't had a kernel upgrade causing any data losses or difficulties.

Things I like about BTRFS:

  • I have had my skin saved because apt automatically creates a btrfs snapshot before major system upgrades
  • I was able to convert an ext4 filesystem to btrfs in place. In production servers, I would have taken a full system backup first, but in local systems I don't have enough space to make full backups. Not making a full backup before major operations is not a good idea, but fortunately all goes well for me, no hitch. Just don't forget to delete the ext snapshot once you're confident of the conversion or your CoW space will keep growing.
  • the btrfs command line interface is IMO, one of the best and most intuitive filesystem command line interface. All the advanced features of btrfs seems accessible and the btrfs wiki fills in the details.
Lie Ryan
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