4 ms·

> Linux has also been developing its own ZFS-like filesystem, btrfs. Since it's been developed in the open (unlike early ZFS), people tried earlier ("IS EXPERIM

> Linux has also been developing its own ZFS-like filesystem, btrfs. Since it's been developed in the open (unlike early ZFS), people tried earlier ("IS EXPERIMENTAL") versions that had serious issues, which gave it something of a bad reputation. It's much better nowadays, and has been integrated in the Linux kernel tree (fs/btrfs), where it is maintained and improved along with the kernel code. Since ZFS is an add-on developed out-of-tree, it will always be harder to get the same level of attention. https://btrfs.wiki.kernel.org/index.php/Status https://btrfs.wiki.kernel.org/index.php/Status So long as there exists code in BTRFS marked "Unstable" (RAID56), I refuse to treat BTRFS as production ready. If it's not ready, fix it or remove it. I consistently run into issues even when using BTRFS in the "mostly OK" RAID1 mode. I don't buy the implication that "it will always be harder to get the same level of attention" will lead to BTRFS being better maintained either. ZFS has most of the same features plus a few extra and unlike BTRFS, they're actually stable and don't break. I'm no ZFS fanboy (my hopes are pinned solidly on bcachefs) but BTRFS just doesn't seem ready for any real use from my experience with it so far and it confuses me. Are BTRFS proponents living in a different reality to me where it doesn't constantly break? EDIT: I realize on writing this that it I might sound more critical of the actual article than I really am. I think his points are mostly fair but I feel this particular line paints BTRFS to have a brighter, more production-ready future than I believe is likely given my experiences with it. BTRFS proponents also rarely point out the issues I have with it so I worry they're not aware of them.

the8472 9y ago
> ZFS has most of the same features plus a few extra The ZFS feature set is not a strict superset of what btrfs offers. The ability to online-restripe between almost any layout combination is quite useful for example. So is on-demand deduplication, which is also far less resource-intensive than ZFS dedup.
- Veratyr 9y ago
  > The ability to online-restripe between almost any layout combination is quite useful for example This is true but since the only stable replication options on BTRFS are RAID1 and single, this online restripe is of very limited usefulness. I'd _really_ like BTRFS to fix its issues so I could use this reshaping (it's the main feature I'm missing from current filesystems) but it's been years and replication is still unstable.
brendangregg 9y ago
We're using both btrfs and zfsonlinux right now, in production, and fortunately we're not consistently running into issues (I'd be hearing about it if we were!). I should note that we do have a higher risk tolerance than many other companies, due to the way the cloud is architected to be fault tolerant. Chaos monkey can just kill instances anytime, and it's designed to handle that. Anyway, getting into specific differences is something that we should blog about at some point (the Titus team).
- Veratyr 9y ago
  Do you use replication at all? I have a feeling the reason why nobody else sees my problems is that most folks will be using a system like Ceph for distributed replication rather than BTRFS for local replication.
- aidenn0 9y ago
  Have you not seen issues with kernel upgrades? I had kernel upgrades cause btrfs to fail to mount as recently as 2016 (at which point I switched to zfs).
antongribok 9y ago
> my hopes are pinned solidly on bcachefs Bcachefs is developed by a single person (however brilliant he may be) on a part time basis (I see only 4 commits since May this year). Unless I'm missing something (please correct me) bcachefs will not be replacing BTRFS, or any other filesystem, anytime soon.
- Veratyr 9y ago
  These are good points and mostly why I said "hopes" rather than something stronger like "bets" or "production machines".
- josephg 9y ago
  > Bcachefs is developed by a single person (however brilliant he may be) on a part time basis (I see only 4 commits since May this year). I'm not sure how true this is of filesystems, but a lot of the best software I know is (or at least, was) developed by a single person. For example, Redis, Sqlite, Lmdb, most malloc implementations, varnishcache, h2o, (nginx?), chipmunk-2d, most of dragonflybsd (including HAMMER). Many projects get more contributors after the code is working well enough to see popular production use. But programmers working alone can accomplish some pretty impressive stuff.
  - user5994461 9y ago
    lmdb/openldap is developed by a commercial company. The other products you mentioned BEGAN with a single person. They had more resources later.
rurban 9y ago
I work with both ZFS and btrfs. btrfs is my fs for almost everything, but the solaris boxes use ZFS. That said, btrfs is far easier to work with. ZFS is a dog when file space gets low, cleanup is troublesome. Never had any btrfs problems, besides ext4 would be faster.

the8472 9y ago

> ZFS has most of the same features plus a few extra The ZFS feature set is not a strict superset of what btrfs offers. The ability to online-restripe between almost any layout combination is quite useful for example. So is on-demand deduplication, which is also far less resource-intensive than ZFS dedup.

Veratyr 9y ago
> The ability to online-restripe between almost any layout combination is quite useful for example This is true but since the only stable replication options on BTRFS are RAID1 and single, this online restripe is of very limited usefulness. I'd _really_ like BTRFS to fix its issues so I could use this reshaping (it's the main feature I'm missing from current filesystems) but it's been years and replication is still unstable.

brendangregg 9y ago

We're using both btrfs and zfsonlinux right now, in production, and fortunately we're not consistently running into issues (I'd be hearing about it if we were!). I should note that we do have a higher risk tolerance than many other companies, due to the way the cloud is architected to be fault tolerant. Chaos monkey can just kill instances anytime, and it's designed to handle that. Anyway, getting into specific differences is something that we should blog about at some point (the Titus team).

Veratyr 9y ago
Do you use replication at all? I have a feeling the reason why nobody else sees my problems is that most folks will be using a system like Ceph for distributed replication rather than BTRFS for local replication.
aidenn0 9y ago
Have you not seen issues with kernel upgrades? I had kernel upgrades cause btrfs to fail to mount as recently as 2016 (at which point I switched to zfs).

antongribok 9y ago

> my hopes are pinned solidly on bcachefs Bcachefs is developed by a single person (however brilliant he may be) on a part time basis (I see only 4 commits since May this year). Unless I'm missing something (please correct me) bcachefs will not be replacing BTRFS, or any other filesystem, anytime soon.

Veratyr 9y ago
These are good points and mostly why I said "hopes" rather than something stronger like "bets" or "production machines".
josephg 9y ago
> Bcachefs is developed by a single person (however brilliant he may be) on a part time basis (I see only 4 commits since May this year). I'm not sure how true this is of filesystems, but a lot of the best software I know is (or at least, was) developed by a single person. For example, Redis, Sqlite, Lmdb, most malloc implementations, varnishcache, h2o, (nginx?), chipmunk-2d, most of dragonflybsd (including HAMMER). Many projects get more contributors after the code is working well enough to see popular production use. But programmers working alone can accomplish some pretty impressive stuff.
- user5994461 9y ago
  lmdb/openldap is developed by a commercial company. The other products you mentioned BEGAN with a single person. They had more resources later.

rurban 9y ago

I work with both ZFS and btrfs. btrfs is my fs for almost everything, but the solaris boxes use ZFS. That said, btrfs is far easier to work with. ZFS is a dog when file space gets low, cleanup is troublesome. Never had any btrfs problems, besides ext4 would be faster.