Btrfs in Linux 6.2 brings performance improvements, better RAID 5/6 reliability • Hacker News Board

Re: Btrfs in Linux 6.2 brings performance improvements, better RAID 5/6 reliability

#21

Post by denkmoon » Mon, Dec 12, 2022, 10:50 PM UTC

candiddevmike wrote: post #8

Maybe I'm just cynical but I think the ship has sailed for BTRFS RAID 5/6. It's now part of the global mindshare that BTRFS RAID 5/6 == data loss, no one wants to be the guinea pig that proves it works. Better to direct resources towards bcachefs or ZFS IMO.

Do Meta not develop btrfs for their internal use? I don't think community sentiment is a big factor for them.

Re: Btrfs in Linux 6.2 brings performance improvements, better RAID 5/6 reliability

#22

Post by warmwaffles » Mon, Dec 12, 2022, 10:52 PM UTC

loeg wrote: post #18

warmwaffles wrote: post #15

Earlier quoted context omitted.

The flexibility of software RAID is nice that you can mix and match hard drive manufacturers and generally have zero issues. For hardware RAID, I've always been told to stick to one drive family from one manufacturer and not to mix and match.

mdadm is software raid; it's just at the block device layer, rather than part of the filesystem.

Oh that's interesting. I've never used mdadm before. At least not knowingly.

Re: Btrfs in Linux 6.2 brings performance improvements, better RAID 5/6 reliability

#23

Post by sliken » Mon, Dec 12, 2022, 10:55 PM UTC

warmwaffles wrote: post #13

kcb wrote: post #7

Earlier quoted context omitted.

Btrfs let me down one time and for a file system one time is too many.

I've been let down by ZFS once before when I wanted to add more drives to an existing pool.

Did you lose data?

Re: Btrfs in Linux 6.2 brings performance improvements, better RAID 5/6 reliability

#24

Post by klysm » Mon, Dec 12, 2022, 10:57 PM UTC

dale_glass wrote: post #19

But is the RAID handling remotely sane yet? See https://arstechnica.com/gadgets/2021/09/examining-btrfs-linu... It has gems such as: * It won't boot on a degraded array by default, requiring manual action to mount it * It won't complain if one of the disks is stale * It won't resilver automatically if a disk is re-added to the array I think the first is the killer. RAID is a High Availability measure. Your system is…

> * It won't boot on a degraded array by default, requiring manual action to mount it

That by itself is a complete deal breaker.

Re: Btrfs in Linux 6.2 brings performance improvements, better RAID 5/6 reliability

#25

Post by [deleted] » Mon, Dec 12, 2022, 10:58 PM UTC

candiddevmike wrote: post #8

Maybe I'm just cynical but I think the ship has sailed for BTRFS RAID 5/6. It's now part of the global mindshare that BTRFS RAID 5/6 == data loss, no one wants to be the guinea pig that proves it works. Better to direct resources towards bcachefs or ZFS IMO.

[deleted]

Re: Btrfs in Linux 6.2 brings performance improvements, better RAID 5/6 reliability

#26

Post by warmwaffles » Mon, Dec 12, 2022, 10:59 PM UTC

sliken wrote: post #23

warmwaffles wrote: post #13

Earlier quoted context omitted.

I've been let down by ZFS once before when I wanted to add more drives to an existing pool.

Did you lose data?

No, and I haven't lost data with BTRFS in RAID6 either.

Re: Btrfs in Linux 6.2 brings performance improvements, better RAID 5/6 reliability

#27

Post by dekhn » Mon, Dec 12, 2022, 10:59 PM UTC

dale_glass wrote: post #19

But is the RAID handling remotely sane yet? See https://arstechnica.com/gadgets/2021/09/examining-btrfs-linu... It has gems such as: * It won't boot on a degraded array by default, requiring manual action to mount it * It won't complain if one of the disks is stale * It won't resilver automatically if a disk is re-added to the array I think the first is the killer. RAID is a High Availability measure. Your system is…

Many folks I know who manage storage don't make the boot volume RAID (redundant)- instead, it's some rapidly duplicatable thing like an NMVE flash containing the root filesystem, and there's a replacement handy. Then you can bring up and bring the full power of userspace to bear on the RAID repair.

Re: Btrfs in Linux 6.2 brings performance improvements, better RAID 5/6 reliability

#28

Post by ansible » Mon, Dec 12, 2022, 11:01 PM UTC

candiddevmike wrote: post #8

Maybe I'm just cynical but I think the ship has sailed for BTRFS RAID 5/6. It's now part of the global mindshare that BTRFS RAID 5/6 == data loss, no one wants to be the guinea pig that proves it works. Better to direct resources towards bcachefs or ZFS IMO.

We had tried RAID-1 on btrfs, and the experience was not that great either. Our current systems, when they use btrfs, are on top of md (mdadm) RAID-1 arrays.

Re: Btrfs in Linux 6.2 brings performance improvements, better RAID 5/6 reliability

#29

Post by oarsinsync » Mon, Dec 12, 2022, 11:01 PM UTC

herpderperator wrote: post #12

I've been managing a raid6 ext4 array with mdadm for 10 years. Started with 4 x 4TB disks and kept adding, up to 11 disks now. It works reliably and as designed. Had a few disk failures and replaced them without issues. That's one of the nice things about mdadm vs ZFS: you can add and remove disks from the array as you see fit, rather than being forced to upgrade all disks if you want to increase the size of your arr…

I did that for a long time. I reached 15 disks. Then something went wrong, and I lost everything. I now run multiple 6 disk raidz2s, in part because I wanted to remove the option that led me down the bad path.

I hope your journey ends better than mine did.

Re: Btrfs in Linux 6.2 brings performance improvements, better RAID 5/6 reliability

#30

Post by Scaevolus » Mon, Dec 12, 2022, 11:03 PM UTC

denkmoon wrote: post #21

candiddevmike wrote: post #8

Maybe I'm just cynical but I think the ship has sailed for BTRFS RAID 5/6. It's now part of the global mindshare that BTRFS RAID 5/6 == data loss, no one wants to be the guinea pig that proves it works. Better to direct resources towards bcachefs or ZFS IMO.

Do Meta not develop btrfs for their internal use? I don't think community sentiment is a big factor for them.

Meta and related companies have much better systems available for durability than RAID5. I would be moderately surprised if they commonly use any standard RAID level.