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ZFS versus RAID: Eight Ironwolf disks, two filesystems, one winner:
This has been a long while in the making—it's test results time. To truly understand the fundamentals of computer storage, it's important to explore the impact of various conventional RAID (Redundant Array of Inexpensive Disks) topologies on performance. It's also important to understand what ZFS is and how it works. But at some point, people (particularly computer enthusiasts on the Internet) want numbers.
First, a quick note: This testing, naturally, builds on those fundamentals. We're going to draw heavily on lessons learned as we explore ZFS topologies here. If you aren't yet entirely solid on the difference between pools and vdevs or what ashift and recordsize mean, we strongly recommend you revisit those explainers before diving into testing and results.
And although everybody loves to see raw numbers, we urge an additional focus on how these figures relate to one another. All of our charts relate the performance of ZFS pool topologies at sizes from two to eight disks to the performance of a single disk. If you change the model of disk, your raw numbers will change accordingly—but for the most part, their relation to a single disk's performance will not.
[It is a long — and detailed — read with quite a few examples and their performance outcomes. Read the 2nd link above to get started and then continue with this story's linked article.--martyb]
Previously:
(2018-09-11) What is ZFS? Why are People Crazy About it?
(2017-07-16) ZFS Is the Best Filesystem (For Now)
(2017-06-24) Playing with ZFS (on Linux) Encryption
(2016-02-18) ZFS is Coming to Ubuntu LTS 16.04
(2016-01-13) The 'Hidden' Cost of Using ZFS for Your Home NAS
(Score: 2) by sjames on Thursday May 21 2020, @07:20PM (4 children)
I would also like to see a comparison with btrfs.
(Score: 2) by hendrikboom on Thursday May 21 2020, @08:12PM (3 children)
I'd like to know whether btrfs is reliable yet. A friend lost his entire btrfs file system a few years ago. Now he uses ext4 on software RAID-1. (that's the keep two copies RAID, right?)
-- hendrik
(Score: 2) by sjames on Thursday May 21 2020, @09:35PM (2 children)
I've been using it on my desktop and a few servers for a couple years now without incident. I know a few NAS devices use btrfs internally.
One caveat, I would avoid raid5/6 mode. It seems that most people who lost data on btrfs were using raid5 mode. I'm not satisfied that those issues have been really been worked out.
Btrfs configured as raid1 did help me out a lot a while back when I had an odd issue with a drive cable corruption a few writes. Thanks to the duplicate data and checksums, btrfs scrub fixed it up without drama (once I replaced the cable, of course).
(Score: 1) by DECbot on Thursday May 21 2020, @10:55PM (1 child)
I heard this too a few years ago on LAS. Btrfs was solid when configured as a mirror but dangerous when setup for RAID 5/6. No clue if those bugs have been worked out or not. This was back when it was time to build a new file server for the basement, and so my options were another RAID5/6 softraid on 16.04, ZFS Z1/Z2 on BSD, or buggy btrfs RAID5/6 on 16.04. I haven't looked into it since as the BSD box is still chugging along.
cats~$ sudo chown -R us /home/base
(Score: 0) by Anonymous Coward on Saturday May 23 2020, @05:53AM
https://btrfs.wiki.kernel.org/index.php/RAID56 [kernel.org]
Basically, they did a major rewrite of the code for RAID 5/6. The result isn't as good as it could be, but it is much less susceptible to problems as the old version. In some ways it is better and some ways it is worse than the ZFS version. Mostly worse, though, as a major problem is that it isn't stable yet..