8 ms·

Does btrfs met your requirements?

nosequel 7y ago
btrfs is not at all reliable, so if you care about your files staying working files, it probably doesn't meet your requirements. It is like the MongoDB 0.1 of filesystems.
- jessant 7y ago
  Seems pretty reliable these days. Are you commenting based upon personal experience? If so, when was it that you used btrfs?
  - reacharavindh 7y ago
    When it comes to file systems “pretty reliable” these days does not sound very good. Reliability had to have been a fundamental requirement for design of a file system. If not, it sounds like putting lipstick on a pig. Redhat throwing towel on their support for development does not instill confidence either. Nothing personally against Btrfs. Just an end user making a file system choice saying what I care about.
    - jessant 7y ago
      re Redhat deprecating btrfs: > People are making a bigger deal of this than it is. Since I left Red Hat in 2012 there hasn't been another engineer to pick up the work, and it is _a lot_ of work. https://news.ycombinator.com/item?id=14909843 https://news.ycombinator.com/item?id=14909843
  - yjftsjthsd-h 7y ago
    I have a laptop running opensuse, with root on btrfs. Twice I have had to reinstall because it managed to corrupt the file system.
Youden 7y ago
I've tried btrfs without much luck. btrfs still has a write hole for RAID5/6 (the kind I primarily use) [0] and has since at least 2012. For a filesystem to have a bug leading to dataloss unpatched for over 8 years is just plain unacceptable. I've also had issues even without RAID, particularly after power outages. Not minor issues but "your filesystem is gone now, sorry" issues. [0]: https://btrfs.wiki.kernel.org/index.php/RAID56 https://btrfs.wiki.kernel.org/index.php/RAID56
- the8472 7y ago
  It's not a bug, but an unimplemented feature. They never made any promise that raid5 is production-ready. Pretty much all software-raid systems suffer from it unless they explicitly patch over it via journaling. Hardware raid gets away with it if it has battery backups, if they don't they suffer from exactly the same problem.
  - mindslight 7y ago
    ... hence the desire to use ZFS, which skips trying to present a single coherent block device and performs parity at the file (chunk) level.
- brianpgordon 7y ago
  My home NAS runs btrfs in RAID 5. The key is to use software RAID / LVM to present a single block device to btrfs. That way you never use btrfs's screwed-up RAID 5/6 implementation.
  - Youden 7y ago
    If you use LVM/mdadm for RAID, it's not possible for btrfs to correct checksum mismatches (i.e. protect against bitrot).
    - brianpgordon 7y ago
      That's a good point, though Synology (my brand of NAS) claims that they've developed analogous corruption checks operating at the LVM level, so you get the benefits of btrfs (including checksum checks and RAID scrubbing) without having to actually use its RAID implementation. https://www.synology.com/en-global/knowledgebase/DSM/help/DSM/StorageManager/storage_pool_data_scrubbing https://www.synology.com/en-global/knowledgebase/DSM/help/DS...

btrfs is not at all reliable, so if you care about your files staying working files, it probably doesn't meet your requirements. It is like the MongoDB 0.1 of filesystems.

jessant 7y ago
Seems pretty reliable these days. Are you commenting based upon personal experience? If so, when was it that you used btrfs?
- reacharavindh 7y ago
  When it comes to file systems “pretty reliable” these days does not sound very good. Reliability had to have been a fundamental requirement for design of a file system. If not, it sounds like putting lipstick on a pig. Redhat throwing towel on their support for development does not instill confidence either. Nothing personally against Btrfs. Just an end user making a file system choice saying what I care about.
  - jessant 7y ago
    re Redhat deprecating btrfs: > People are making a bigger deal of this than it is. Since I left Red Hat in 2012 there hasn't been another engineer to pick up the work, and it is _a lot_ of work. https://news.ycombinator.com/item?id=14909843 https://news.ycombinator.com/item?id=14909843
- yjftsjthsd-h 7y ago
  I have a laptop running opensuse, with root on btrfs. Twice I have had to reinstall because it managed to corrupt the file system.

Youden 7y ago

I've tried btrfs without much luck. btrfs still has a write hole for RAID5/6 (the kind I primarily use) [0] and has since at least 2012. For a filesystem to have a bug leading to dataloss unpatched for over 8 years is just plain unacceptable. I've also had issues even without RAID, particularly after power outages. Not minor issues but "your filesystem is gone now, sorry" issues. [0]: https://btrfs.wiki.kernel.org/index.php/RAID56 https://btrfs.wiki.kernel.org/index.php/RAID56

the8472 7y ago
It's not a bug, but an unimplemented feature. They never made any promise that raid5 is production-ready. Pretty much all software-raid systems suffer from it unless they explicitly patch over it via journaling. Hardware raid gets away with it if it has battery backups, if they don't they suffer from exactly the same problem.
- mindslight 7y ago
  ... hence the desire to use ZFS, which skips trying to present a single coherent block device and performs parity at the file (chunk) level.
brianpgordon 7y ago
My home NAS runs btrfs in RAID 5. The key is to use software RAID / LVM to present a single block device to btrfs. That way you never use btrfs's screwed-up RAID 5/6 implementation.
- Youden 7y ago
  If you use LVM/mdadm for RAID, it's not possible for btrfs to correct checksum mismatches (i.e. protect against bitrot).
  - brianpgordon 7y ago
    That's a good point, though Synology (my brand of NAS) claims that they've developed analogous corruption checks operating at the LVM level, so you get the benefits of btrfs (including checksum checks and RAID scrubbing) without having to actually use its RAID implementation. https://www.synology.com/en-global/knowledgebase/DSM/help/DSM/StorageManager/storage_pool_data_scrubbing https://www.synology.com/en-global/knowledgebase/DSM/help/DS...