3 ms·

Which raid level were you using over those multiple disks? I've been using btrfs and never even experienced a hiccup despite continuous sector failures, continu

by RX14 9y ago

Which raid level were you using over those multiple disks? I've been using btrfs and never even experienced a hiccup despite continuous sector failures, continuous drive failures and even disk controllers disconnecting on the fly. And I've been running the whole thing on a single, fairly weak, server with second-hand disks attached over the cheapest USB3 sata adapters I've found. By all accounts I've been putting btrfs in a situation that is well outside the norm and I have 0 complaints. I also use it on my desktop (no raid) with similar experience (minus the shitty hardware). I am continuously amazed at the amount of people who have issues with btrfs. It's been absolutely rock solid over the time I've used it and I have 0 complaints (apart from the ext4 -> btrfs converter producing a corrupted btrfs filesystem, but the actual kernel btrfs code itself has been flawless).

btmaybe 9y ago
I too have lost an entire btrfs volume (single disk) because of a bad sector. It seems btrfs is very sensitive to bad sectors in metadata, compared to ext4. Since then, I've formatted my btrfs partition to do RAID1 on metadata and haven't had problems since. $ sudo btrfs fi df / Data, single System, DUP Metadata, DUP
- Dylan16807 9y ago
  Isn't that the default?
  - sp332 9y ago
    "A single device filesystem will default [metadata] to DUP, unless a SSD is detected. Then it will default to single." https://btrfs.wiki.kernel.org/index.php/Manpage/mkfs.btrfs#OPTIONS https://btrfs.wiki.kernel.org/index.php/Manpage/mkfs.btrfs#O...
  - btmaybe 9y ago
    It's a relatively new feature (Jan-2016) and it's disabled by default for SSD devices (increased wear). Personally I prefer increased wear over unmountable volumes.
- jacknews 9y ago
  Perhaps this is the secret - and should be made the default. I don't use raid, precisely because I'm worried that failures will take down the entire set, and all of it will be unrecoverable. I'm not at all suggesting that BTRFS is "buggy" unreliable, just, as you say, with certain kinds of disk errors (possibly rare, but it got me), the entire volume becomes unreadable, whereas I've always been able to recover files from extX or xfs volumes. Perhaps it's just my bad luck though.
  - RX14 9y ago
    The default for single devices is to have DUP metadata, and for raid1 devices the default is raid1 metadata. These are the defaults, somehow they got bypassed. I think you're right that you need to think a little more and know a little more about btrfs to use it properly, but I hope that will change in the future.
- pnutjam 9y ago
  From the article: 'And against the demand of some partners, we are still refusing to support “Automatic Defragmentation”, “In-band Deduplication” and higher RAID levels, because the quality of these options is not where it ought to be.' I've only used btrfs on single disk systems.
atomi 9y ago
I have the same experience. btrfs has been great to me. I've disconnected disks on the fly as well on raid 1 and the mount is happily serving files off the remaining disks.

by RX14 9y ago

btmaybe 9y ago

I too have lost an entire btrfs volume (single disk) because of a bad sector. It seems btrfs is very sensitive to bad sectors in metadata, compared to ext4. Since then, I've formatted my btrfs partition to do RAID1 on metadata and haven't had problems since. $ sudo btrfs fi df / Data, single System, DUP Metadata, DUP

Dylan16807 9y ago
Isn't that the default?
- sp332 9y ago
  "A single device filesystem will default [metadata] to DUP, unless a SSD is detected. Then it will default to single." https://btrfs.wiki.kernel.org/index.php/Manpage/mkfs.btrfs#OPTIONS https://btrfs.wiki.kernel.org/index.php/Manpage/mkfs.btrfs#O...
- btmaybe 9y ago
  It's a relatively new feature (Jan-2016) and it's disabled by default for SSD devices (increased wear). Personally I prefer increased wear over unmountable volumes.
jacknews 9y ago
Perhaps this is the secret - and should be made the default. I don't use raid, precisely because I'm worried that failures will take down the entire set, and all of it will be unrecoverable. I'm not at all suggesting that BTRFS is "buggy" unreliable, just, as you say, with certain kinds of disk errors (possibly rare, but it got me), the entire volume becomes unreadable, whereas I've always been able to recover files from extX or xfs volumes. Perhaps it's just my bad luck though.
- RX14 9y ago
  The default for single devices is to have DUP metadata, and for raid1 devices the default is raid1 metadata. These are the defaults, somehow they got bypassed. I think you're right that you need to think a little more and know a little more about btrfs to use it properly, but I hope that will change in the future.
pnutjam 9y ago
From the article: 'And against the demand of some partners, we are still refusing to support “Automatic Defragmentation”, “In-band Deduplication” and higher RAID levels, because the quality of these options is not where it ought to be.' I've only used btrfs on single disk systems.

atomi 9y ago

I have the same experience. btrfs has been great to me. I've disconnected disks on the fly as well on raid 1 and the mount is happily serving files off the remaining disks.