One time I had a power outage and one of the btrfs hds (not in a raid) couldn't be read anymore after reboot. Even with help from the (official) btrfs mailinglist It was impossible to repair the file system. After a lot of low level tinkering I was able to retrieve the files, but the file system itself was absolutely broken, no repair process was possible. I since switched to zfs, the emergency options are much more capable.

If it didn't give you problems, go for it. I've run it for years and never had issues either.

Not proxmox-specific, but I've been using btrfs on my servers and laptops for the past 6 years with zero issues. The only times it's bugged out is due to bad hardware, and having the filesystem shouting at me to make me aware of that was fantastic.

The only place I don't use zfs is for my nas data drives (since I want raidz2, and btrfs raid5 is hella shady) but the nas rootfs is btrfs.

I run it now because I wanted to try it. I haven't had any issues. A friend recommended it as a stable option.

Meh. I run proxmox and other boot drives on ext4, data drives on xfs. I don't have any need for additional features in btrfs. Shrinking would be nice, so maybe someday I'll use ext4 for data too.

I started with zfs instead of RAID, but I found I spent way too much time trying to manage RAM and tuning it, whereas I could just configure RAID 10 once and be done with it. The performance differences are insignificant, since most of the work it does happens in the background.

You can benchmark them if you care about performance. You can find plenty of discussion by googling "ext vs xfs vs btrfs" or whichever ones you're considering. They haven't changed that much in the past few years.

Btrfs only has issues with raid 5. Works well for raid 1 and 0. No reason to change if it works for you

Using it here. Love the flexibility and features.

Do you rely on snapshotting and journaling? If so backup your snapshots.