About a year ago I switched to ZFS for Proxmox so that I wouldn't be running technology preview.
Btrfs gave me no issues for years and I even replaced a dying disk with no issues. I use raid 1 for my Proxmox machines. Anyway I moved to ZFS and it has been a less that ideal experience. The separate kernel modules mean that I can't downgrade the kernel plus the performance on my hardware is abysmal. I get only like 50-100mb/s vs the several hundred I would get with btrfs.
Any reason I shouldn't go back to btrfs? There seems to be a community fear of btrfs eating data or having unexplainable errors. That is sad to hear as btrfs has had lots of time to mature in the last 8 years. I would never have considered it 5-6 years ago but now it seems like a solid choice.
Anyone else pondering or using btrfs? It seems like a solid choice.
You've been downvoted, but I've seen a fair share of ZFS implementations confirm your assessment.
E.g. "Don't use ZFS if you care about performance, especially on SSD" is a fairly common refrain in response to anyone asking about how to get the best performance out of their solution.
I used to run a mirror for a while with WD USB disks. Didn't notice any performance problems. Used Ubuntu LTS which has a built-in ZFS module, not DKMS, although I doubt there's performance problems stemming from DKMS.
I have been trying to get ZFS working well for months. Also I am not the only one having issues as I have seen lots of other posts about similar problems.
I don't doubt that you have problems with your setup. Given the large number of (simple) zfs setups that are working flawlessly there are a bound to be a large number of issues to be found on the Internet.
People that are discontent voice their opinion more often and loudly compared to the people that are satisfied.
That doesn't speak much of the architecture. Also it's really odd. Not denying what you're seeing is happening, just that it seems odd based on the setups I run with ZFS. My main server is in fact a shared machine that I use as a workstation and games along as a server. All works in parallel. I used to have a mirror, then a 4-disk RAIDz and now an 8-disk RAIDz2. I have multiple applications constantly using the pool. I don't notice any performance slowdowns on the desktop, or in-game when IO goes high. The only time I notice anything is when something like multiple Plex transcoders hit the CPU hard. Sequential performance is around 1.3GB/s which is limited by the data bus speeds (USB DAS boxes). Random performance is very good although I don't have any numbers out of my head. I'm using mostly WD Elements shucked disks and a couple of IronWolfs. No enterprise grade disks on this system.
I'm also not saying that you have to keep fucking around with it instead of going Btrfs. Simply adding another anecdote to the picture. If I had a serious problem like that and couldn't figure it out I'd be on LVMRAID+Ext4 which is what used prior to ZFS.
The list is endless. Maybe BTRFS is more tolerant of the problems you're facing, but that doesn't mean the problems are specific to ZFS. I recommend doing a bit of testing to see if everything looks fine on the HW side of things (memtest, smart tests, etc).