On Thu, Feb 21, 2013 at 06:47:28PM +0100, Swâmi Petaramesh wrote: > Le 21/02/2013 18:25, Hugo Mills a écrit : > > Correct. But btrfs isn't at that stage yet. It's getting visibly > > closer, but it's not quite there. Hence the very strong recommendation > > to keep up with the latest code. Hugo. > > The matter is that BTRFS had many early adopters just because it is - > and has been for long now - in the mainline Linux kernel, so supposed > stable and good choice for the future.
I'm afraid that's not actually a valid conclusion. Just because something makes it into the mainline kernel, it doesn't mean that it's considered stable -- just that any instabilities aren't going to affect the rest of the kernel. > To be honest (and not wanting to troll, promised) this is the only > single reason for which I use BTRFS on 5 of my 6 machines at home - just > because I thought that "Just upgrade the distro every 6 months and it > will become better and better over time, no hassle, make my life easy". That approach means you're still somewhere between 1 and 3 kernel versions out of date, on something which is still undergoing significant changes on most kernel releases. > OTOH my 6th machine runs native ZFS on Linux, and I have to tell that it > shows orders of magnitude better performance and never gave me a single > problem in several (3 ?) years. Only upgrading the distro is always a > big frightening and problematic. And initial installation was a bit tricky. ZFS has had something like an extra 5 years of development on it, so it's not surprising that it's more stable. > Probably a lot of BTRS early adopters choosed it for the same reason why > I did : Included in the standard kernel, easy to install, and *expected* > to improve quickly But you don't get the improvements if you don't get the kernels... > - yes, I already made the move back and forth twice, > between ext4 and BTRFS, on 2 machines... About one year ago I choosed to > jump "for good" and stay, but performance degrades so quickly and so > much that every couple of days I wonder if I won't rollback to ex4 again > (and again), or shift to ZFS once for all and just forget about it... Performance was greatly improved in 3.7. You may also find performance problems with a very full filesystem, or with workloads which write heavily to one file (databases, and bitcoin's DB in particular). The latter issue can largely be dealt with by judicious use of nocow attributes. Plus go for 3.7 or later anyway. > Everytime I show my Linux machines to friends and say : “Hey, I got the > most advanced filesystem on earth !” I soon get the answer “Oh boy, > that's the slowest machine boot and FS I've ever seen since I was > reading floppy disks on my 386SX in 1991 ! Can you really live with this ?” > > So, for "not quite there" and the return codes "+20" that have been a > minor pain in the arse for a couple years but the line is still in the > code... There's been about one question (not even complaint) about that return code every... maybe 3-6 months? It's not high on the list of priorities of things to fix, compared to some of the other problems that have shown up, or even the repeated questions (like mis-interpretation of the output of df, btrfs fi df and btrfs fi show). > I can understand developer's PoV, been there, done that, but > still, BTRFS might in the end lose a numer of its early adopters if it > keeps being "not quite there" too long. > > Shitfing to ZFS is just a PPA and 2 apt-get install commands away... It > will definitely be easier than start playing with mainline PPA Ubuntu > kernels... Well, given that btrfs is still getting at least one significant fix to a major bug or set of fixes in every release, it would still seem sensible to keep up with the latest developments. If that's not what you expected, then I'm sorry if we've failed to get the point across. We do try to manage expectations on the btrfs website, and we're quite up-front about the need for keeping up with releases there. If that's more than you want to do, that's OK -- I wouldn't expect it to be something that everyone would want to do. Many people do keep up with the kernels through the Ubuntu PPA (or other, similar repositories for other distributions), and don't have problems. If it doesn't work out for you, then parting company without rancour or prejudice may be the best thing. Temporarily, I hope, of course. Hugo. -- === Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk === PGP key: 515C238D from wwwkeys.eu.pgp.net or http://www.carfax.org.uk --- I get nervous when I see words like 'mayhaps' in a novel, --- because I fear that just round the corner is lurking 'forsooth'
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