Selfhosted

You shouldn't have abysmal performance with ZFS. Something must be up.

One day I had a power outage and I wasn't able to mount the btrfs system disk anymore. I could mount it in another Linux but I wasn't able to boot from it anymore. I was very pissed, lost a whole day of work

Don't use btrfs if you need RAID 5 or 6.

The RAID56 feature provides striping and parity over several devices, same as the traditional RAID5/6. There are some implementation and design deficiencies that make it unreliable for some corner cases and the feature should not be used in production, only for evaluation or testing. The power failure safety for metadata with RAID56 is not 100%.

https://btrfs.readthedocs.io/en/latest/btrfs-man5.html#raid56-status-and-recommended-practices

I've been using single-disk btrfs for my rootfs on every system for almost a decade. Great for snapshots while still being an in-tree driver. I also like being able to use subvolumes to treat / and /home (maybe others) similar to separate filesystems without actually being different partitions.

I had used it for my NAS array too, with btrfs raid1 (on top of luks), but migrated that over to ZFS a couple years ago because I wanted to get more usable storage space for the same money. btrfs raid5 is widely reported to be flawed and seemed to be in purgatory of never being fixed, so I moved to raidz1 instead.

One thing I miss is heterogenous arrays: with btrfs I can gradually upgrade my storage one disk at a time (without rewriting the filesystem) and it uses all of my space. For example, two 12TB drives, two 8TB drives, and one 4TB drive adds up to 44TB and raid1 cuts that in half to 22TB effective space. ZFS doesn't do that. Before I could migrate to ZFS I had to commit to buying a bunch of new drives (5x12TB not counting the backup array) so that every drive is the same size and I felt confident it would be enough space to last me a long time since growing it after the fact is a burden.

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.

A bit of topic; am I the only one that pronounces it "butterface"?

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.

No reason not to. Old reputations die hard, but it's been many many years since I've had an issue.

I like also that btrfs is a lot more flexible than ZFS which is pretty strict about the size and number of disks, whereas you can upgrade a btrfs array ad hoc.

I'll add to avoid RAID5/6 as that is still not considered safe, but you mentioned RAID1 which has no issues.

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

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.

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

Using it here. Love the flexibility and features.

Used it in development environment, well I didn't need the snapshot feature and it didn't have a straightforward swap setup, it lead to performance issues because of frequent writes to swap.

Not a big issue but annoyed me a bit.

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

The question is how do you get a bad performance with ZFS?

I just tried to read a large file and it gave me uncached 280 MB/s from two mirrored HDDs.

The fourth run (obviously cached) gave me over 3.8 GB/s.

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