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Comment by insaneirish | Hacker News Reader

I'm going to be blunt for a moment. If you are not using ZFS, you deserve what you get.

As the author realizes, hardware RAID, or naive software RAID, is becoming more and more useless given the size of volumes and the bit densities (and thus error rates) of those drives.

The only solution to this is a proper file system and volume manager that can proactively discover bit rot and give you time to do something about it. At the moment, the only real solution is ZFS.

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ZFS is great, possibly the closest to perfection available at any price today.

But theres a word beginning with "O" and ending with "racle", they are so focused on the short term buck they are massacring their potential revenues with their short sighted approach of keeping Solaris out of everyone's hands.

... which is why you should be using FreeBSD.

For several reasons (now including coughunitycough), I wish I had built my in-basement cluster with freebsd rather than ubuntu. Likely I will move the boxes over one-by-one.

The Linux answer to ZFS is btrfs, and it's almost ready to go.

Call me when btrfs has parity.

What's it waiting on, and who other than Val is working on it?

Answering my own question: http://git.kernel.org/?p=linux/kernel/git/mason/btrfs-progs....

... and Valerie Auror's less active on that than I'd thought. Hrm.

That's only true for open source implementations (if you can call ZFS that, the only really decent implementation is still locked up inside Oracle). Netapp's WAFL (which ZFS copied) is the original implementation of a RAID system that is resilient to bit rot and the other array vendors (EMC, HDS etc) all have similar systems.

What features are open source ZFS implementations (ZFS v28) lacking to that on Solaris aside from encryption? I run a 6-drive raidz2 array on my FreeBSD workstation, and I put it through its paces, and it's pretty awesome. Rock solid stable, in my experience.

I hear TRIM support for ZFS is now in the HEAD branch and in the works for FreeBSD 10.

ZFS is beautiful and wonderful, but my perhaps outdated understanding is that the Linux port isn't as stable or mature as it is elsewhere. Is that not true? Or is it that the advantages of ZFS are so great that people should switch to illumos or some BSD?

> the Linux port isn't as stable or mature as it is elsewhere.

Which one: the FUSE one, or the native ZFS on Linux under CDDL?

I haven't used the FUSE one extensively but the native one kept leaking memory until the system was exhausted. (Specifically it did this whenever I messed with a large number of files, I'm sure it works fine for media storage as StavrosK says.)

I haven't used the Linux version in a while, but as it's not a first class citizen of the kernel, I don't think it will ever be the same as a BSD implementation. In my opinion, if you're doing anything with storage, you'd be crazy not to use ZFS, even if that means learning a new OS/kernel.

I'm using zfsonlinux on Ubuntu, and so far (months) it has been solid. Granted, it's just for media storage, but it's fine.

How does ZFS discover bit rot if you don't read the bits? I have mine scrubbing once a week, is that unnecessary?

ZFS auto-heals on read so the files you touch regularly are fine. You do need to scrub regularly to prevent bit-rot across all your files. I go with once-a-week as well.

so how is that better than raid? it sounds identical to what is described in the article - the problem was not scrubbing (afaict).

ZFS is at the file level, not the disk level. So recovering from errors (i.e. rebuilds) is MUCH faster.

Only when the array is mostly empty. For several years hardware RAID controllers have been rebuilding only used space, too. Really, ZFS isn't that much of the miracle some want it to be.

How do they know what space is used or unused?

Apparently they keep a block list somewhere.

but that's not what we were talking about! no-one was saying "zfs sucks as much as raid but at least it rebuilds faster afterwards". the implication was that zfs avoided the problem in the article (when, it seems, both zfs and raid need to be scrubbed, and both avoid the problem when that is done).

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