Btrfs For Linux 6.6 Brings Fixes, Partially Recovers From Scrub Performance Regression

[Rovano]

When that issue happens, I can't do anything because Steam took down the gui session with it, so everything just becomes frozen. So no keyboard shortcuts help.

Regarding fsck, I wouldn't call myself a Linux noob, but I'm no expert either, so while I really want to do it after those 2 hard reboots caused by Steam, I already gave up multiple times because I can't find a clear step by step tutorial on how to properly do it. (I just know you need to reboot into safe mode or something). I really miss that on Windows you could just go to disk properties and check for filesystem errors without even rebooting.

The system disk Windows cannot be repaired this way.

[user1]

The system disk Windows cannot be repaired this way.

If there are errors found, then of course you'll have to reboot in order to fix them. But starting with Windows 8 it's possible to just check for filesystem errors on system disk while Windows is already running.

[piorunz]

Very happy with Btrfs, been for 6-7 years. My original filesystem on homeserver has seen migration at least 3-4 times, from small to medium to big drives, changing from single to raid 1 then to raid10, replacing broken drives, correcting RAM bit flips, always rock solid.
Now I am replacing 2 SSD drives in my main computer. Doing so by adding extra HDD, degrading to single, then removing 2 old drives, next week I will add two new drives, upgrade to raid 1, balance and remove spare HDD. All while not even turning off my computer for a minute. And I am replacing these SSD drives because they are unreliable, and going offline sometimes. Never lost a byte thanks to raid1 Btrfs, it always correcting both mirrors, even if one was offline.
Can your filesystem do that? 🥰

[Azpegath]

Note that many of the errors shown/discovered via btrfs check does not lead to actual data errors on the data stored, that btrfs scrub shows no errors tells that all your files are ok. Ext4, XFS and many other filesystems are full of these type of errors but their structure makes them non detectable so that is why it often looks like btrfs have errors (from btrfs check) vs the others.

I think that they can lead to loss of available space later on since I would guess that many of them are simply wrong ref counts on no longer used COW data (aka old versions of files are still kept hidden on disk since the reference count is wrong). Least stressful fix is to add new drives and do a file copy from the old to the new, riskier fix is to boot via livecd and do check+repair on the unmounted device.

Thank you, that is somewhat reassuring... One issue is adding new disks, I don't have more disks and don't plan to get one right now. I was hoping the mirroring would lessen my risk of dataloss.

One solution would be to use one of the disks in the mirror and reinitialize that, and copy the data from the other mirror. And then mirror it again.

That would give me more than enough space to do the same with the 3rd disk, since that is smaller.

[F.Ultra]

Thank you, that is somewhat reassuring... One issue is adding new disks, I don't have more disks and don't plan to get one right now. I was hoping the mirroring would lessen my risk of dataloss.

One solution would be to use one of the disks in the mirror and reinitialize that, and copy the data from the other mirror. And then mirror it again.

That would give me more than enough space to do the same with the 3rd disk, since that is smaller.

Yes the mirroring means that you have less risk of dataloss and I would also make the claim that you are in no risk of dataloss either. For adding new drives I can highly recommend PCIe adaptors for nvme, they are usually very cheap and you can easily add 2 or more nvmes to any system with a free PCIe slot and then once done can move the drives from the card to the motherboard for the higher speed.

You ofc can remove one of the drives from the mirror, reinitialize it, copy the stuff there and then add the first drive to the mirror but what I don't like about that is that it does rearrange stuff on the existing drives and that is always an added risk (not to mention that while it happens you don't have a mirror if anything goes wrong).

Also one thing to make sure of is that the meta data is also mirrored, lots of people who set up btrfs in raid 1c2 usually have the meta data left as single so it is always best to make sure that the MetaData row is also set to Raid1 and not single like below:

root@fileserver-sth1:~# btrfs filesystem df /opt
Data, RAID10: total=41.10TiB, used=41.09TiB
System, RAID10: total=18.00MiB, used=5.14MiB
Metadata, RAID10: total=52.31GiB, used=51.33GiB
GlobalReserve, single: total=512.00MiB, used=0.00B
root@fileserver-sth1:~#

[EmanuC]

I think it's been abandoned for now. The branches are stale:

https://github.com/josefbacik/linux/branches

Block group tree was a big part of the original idea, and thats' been merged in linux for a while now (I'm a happy user of it). I don't think there was much buy in from other devs for the rest of extent v2. And there's plenty of work that will minimize contention without the partitioning that extentv2 would introduce so I think that's were all the effort has been spent. Maybe when that effort has been exhausted they'll look at this idea again.

It seems like no: https://github.com/josefbacik/btrfs-...s/global-roots

The extent tree v2 is a big change and we try to extract useful features in advance

https://www.reddit.com/r/linux/comments/13v4q3j/comment/jmes7m1/?utm_source=share&utm_medium=web2x&context=3

[Rovano]

If there are errors found, then of course you'll have to reboot in order to fix them. But starting with Windows 8 it's possible to just check for filesystem errors on system disk while Windows is already running.

Yes, it is possible to do this. But in practice it is useless. NTFS almost always contains errors after such a reset, which are good to fix.