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Ubuntu 16.04 LTS To Have Official Support For ZFS File System (dustinkirkland.com)
LichtSpektren writes: Ubuntu developer Dustin Kirkland has posted on his blog that Canonical plans to officially support the ZFS file system for the next Ubuntu LTS release, 16.04 "Xenial Xerus." The file system, which originates in Solaris UNIX, is renowned for its feature set (Kirkland touts "snapshots, copy-on-write cloning, continuous integrity checking against data corruption, automatic repair, efficient data compression") and its stability. "You'll find zfs.ko automatically built and installed on your Ubuntu systems. No more DKMS-built modules!" N.B. ext4 will still be the default file system due to the unresolved licensing conflict between Linux's GPLv2 and ZFS's CDDL.
As a die hard BTRFS user that chases kernel releases like a addict chases crack, I can't help but say that there are still some annoying issues out there.
While none have given me data loss, you'll get the occasional deadlock from a set of kthreads that do compression or a severe slowdown with next to no disk I/O and big WAITIO (usually get 16.xx Load in such cases on a quad core machine). For the slowdown case you'll get a speed drop from 150MB/s to 900~KB/s on spinning rust for a couple of minutes. Happens only after heavy use in the range of 2+TB written with forced compression.
ENOSPC? Not on my end. Trying to copy a file and running out of space results in WAITIO through the roof while BTRFS tries to find free space. I've had a job that stalled and thrashed the hard drive for 9 hours while it tried to recover space. At no point did it simply kill the transfer due to out of space, btrfs usage showed around 1GB of space left with plenty for metadata. It's at 1GB free for data extents and that's what kills the whole deal. You can't use that last 1GB, you'll just deadlock until some space is recovered by deleting files manually. Happens every time, just make sure to transfer something that is larger than the available free space and watch it suffer.
All this with Linux kernel 4.4.2. Looking at the various mailing lists with regular posts from people with obscure problems I've never encountered before, can't really say it's on par with ZFS stability. And ZFS On Linux is still missing a few things last I checked from the true ZFS implementation, but it's usable. Can't comment on ZOL long term stability, but I would feel comfortable enough using it instead of BTRFS for say a production server.