Fedora ZFS

Further to my recent post, the good news is that the ZFS team have released a version of ZFS which will work on the latest Fedora:

The version supports kernels up to 4.10 (which is handy, as that’s the next kernel release I can upgrade my Fedora 25 to, so there’s some future-proofing going on there at last). And I can confirm that, indeed, ZFS installs correctly now.

I’m still a bit dubious about ZFS on a fast-moving distro such as Fedora, though, because just a single kernel update could potentially render your data inaccessible until the good folk at the ZFS development team decide to release new kernel drivers to match. But the situation is at least better than it was.

With a move to the UK pending, I am disinclined to suddenly start wiping terabytes of hard disk and dabbling with a new file system… but give it a few weeks and who knows?!

Must… Lock… Wallet… Away…

I didn’t know this site existed until today, but it’s fair to say that since I found it (courtesy of a link on the Peppermint Linux website), I am having difficulties keeping my wallet closed.

ToH will not approve of the extravagance of Linux embroidery on my t-shirts, however, so it might (unfortunately) be easier to hold fire than I had first thought… but who knows how long I shall be able to hold out?!

Sadly, they don’t do a Fedora one. Or a Manjaro one.

Mercifully, they don’t do an Oracle Enterprise one either (I guess the t-shirt would have to be tomato red if they did).

The SUSE chameleon one is really nice… but I don’t run that these days, so wearing it would just make me a fraud. Same goes for the Debian swirl-only…

So I figure I may have to settle for a simple Tux logo.

Unless I change my main desktop distro again. Hmmm…

Fed Up, Zed Up?

Spot the problem shown in these two screen grabs:

You will immediately notice from the second screenshot that version of whatever it is which happens to have been screenshotted only supports up to 4.8 kernels, whereas the first screenshot shows that a Fedora 25 installation is using kernel version 4.9. Clearly that Fedora installation won’t be able to run whatever is being referred to in the second screenshot.

So what is it that I’ve taken that second screen shot of? This:

Ooops. It happens to be a screenshot of the current stable release number of the world’s greatest file system for Linux.

Put together, and in plain English, the combination of the two version numbers means: I can’t install ZFS on Fedora.

Or rather, I could have done so when Fedora 25 was freshly installed, straight off the DVD (because it ships with a 4.8 kernel, so the version of ZFS would have worked just fine on that). ZFS on 4.8-kernel-using-Fedora 25 works fine, therefore.

But if I had, say, copied 4.8TB of data onto a freshly created zpool and then updated Fedora, I would now not be able to access my 4.8TB of data at all (because the relevant ZFS kernel modules won’t be able to load into the newly-installed 4.9 kernel). Which sort of makes the ZFS file system a bit less than useful, no?!

Of course, once they release version 0.7 version of ZFS (which is currently at release candidate 2 state), then we’re back in business -because ZFS 0.7 supports 4.9 kernels. Unless Fedora go and update themselves to using kernel 4.10, of course… in which case it’s presumably back to being inaccessible once more. And so, in cat-and-mouse fashion, ad infinitum…

But here’s the thing: Fedora is, by design, bleeding edge, cutting edge… you name your edge, Fedora is supposed to be on it! So it is likely to be getting new kernel releases every alternate Thursday afternoon, probably. What chance the ZFS developers will match that release cadence, do you think… given that their last stable release is now 4 months old?

About zilch I’d say. Which gives rise to a certain ‘impedance mismatch’, no? Try running ZFS on Fedora, it seems to me, and you’ll be consigning yourself to quite regularly not being able to access your data at all for weeks or months on end, several times a year. (Point releases of the 4.x kernel have been coming every two or three months since 4.0 was unleashed in April 2015, after all).

It strikes me that ZFS and Fedora are, in consequence, not likely to be good bed-fellows, which is a shame.

Perhaps it is time to investigate the data preservative characteristics of Btrfs at last?!

Incidentally, try installing ZFS on a 4.9-kernel-using-Fedora 25 whilst the version of ZFS is the latest-and-greatest on offer and the error you’ll get is this:

The keywords to look for are ‘Bad return status’ and ‘spl-dkms scriptlet failed’. Both mean that the spl-dkms package didn’t get installed, and the net effect of that is the ZFS kernel modules don’t get loaded. In turn, this means trying to issue any ZFS-related commands will fail:

Of course, you will think that you should then do as the error message tells you: run ‘/sbin/modprobe zfs’ manually. It’s only when you try to do so you see the more fundamental problem:

And there’s no coming back from that. 🙁

No practical ZFS for a distro? That’s a bit of a deal-breaker for me these days.