3 ms·

Oh. He's using Linux 4.0? That's an old kernel if you're running btrfs. I hope that he re-tests with 4.2 [0] or 4.3. I also hope that he posts his benchmark set

Oh. He's using Linux 4.0? That's an old kernel if you're running btrfs. I hope that he re-tests with 4.2 [0] or 4.3. I also hope that he posts his benchmark settings so I can run it on my systems at home. :) I'm very curious about the ENOSPC errors. Also, the linux-btrfs mailing list thread about the rant is somewhat worth reading, if you're into this sort of thing: http://thread.gmane.org/gmane.comp.file-systems.btrfs/48248 http://thread.gmane.org/gmane.comp.file-systems.btrfs/48248 [0] There's a mv/rm deadlock that I can trigger from time to time that was only fixed in 4.2 and later. (His description of the test stall doesn't indicate that this deadlock is the cause of his problem, mind.) Happily, this deadlock only blocks operations on the file being operated on, rather than the whole FS. Also, a reboot clears up the issue. (An umount, then mount might also clear up the issue, but btrfs is my rootfs, so I can't test that. :P)

semi-extrinsic 11y ago
The author adresses this issue very eloquently: if your file system requires a Linux kernel newer than 4.0 to get decent performance, it is very hard to argue that it is "mature" and "production-ready".
- simoncion 11y ago
  > The author adresses this issue very eloquently... That would be one of the reasons why I never made the claim that btrfs is ready for general use in all situations. :) I mean, in my footnote I mention that I'm running into a deadlock triggered by perfectly ordinary filesystem operations.
pgaddict 11y ago
Yes, I'll publish the data soon. I've planned to do that before the talk at pgconf.eu (end of October in Vienna) where I'll talk about the results. But given the current interest, I'll probably do that sooner, given the interest. I've used kernel 4.0 because that's what was latest in May when I started with the benchmark - it takes ~3-4 days to test a single configuration and you can't simply change the kernel halfway through. Also, as pointed out by semi-extrinsic, if you have to use bleeding-edge kernel, it probably is not mature enough for general use. FWIW, I haven't really expected the rant to get discussed on linux-btrfs, but I'm nicely surprised by how polite and factual the posts are. They got most of the facts right and the inaccuracies are mostly minor and probably a consequence of the rant not providing all the data.
- simoncion 11y ago
  > ...it takes ~3-4 days to test a single configuration and you can't simply change the kernel halfway through. No worries! I've done very-long-running testing before. Moreover, your blog post made it very clear that you're not some n00b with an axe to grind. :) I wonder if it'll take substantially longer than 3->4 days for my systems to complete a test. Guess I'll find out within a few months! :D :D :D > ...I'm nicely surprised by how polite and factual the posts are. Yeah, the btrfs devs strike me as a really nice bunch of folks. Anyway, thanks for the info and the comment! :D

semi-extrinsic 11y ago

The author adresses this issue very eloquently: if your file system requires a Linux kernel newer than 4.0 to get decent performance, it is very hard to argue that it is "mature" and "production-ready".

simoncion 11y ago
> The author adresses this issue very eloquently... That would be one of the reasons why I never made the claim that btrfs is ready for general use in all situations. :) I mean, in my footnote I mention that I'm running into a deadlock triggered by perfectly ordinary filesystem operations.

pgaddict 11y ago

Yes, I'll publish the data soon. I've planned to do that before the talk at pgconf.eu (end of October in Vienna) where I'll talk about the results. But given the current interest, I'll probably do that sooner, given the interest. I've used kernel 4.0 because that's what was latest in May when I started with the benchmark - it takes ~3-4 days to test a single configuration and you can't simply change the kernel halfway through. Also, as pointed out by semi-extrinsic, if you have to use bleeding-edge kernel, it probably is not mature enough for general use. FWIW, I haven't really expected the rant to get discussed on linux-btrfs, but I'm nicely surprised by how polite and factual the posts are. They got most of the facts right and the inaccuracies are mostly minor and probably a consequence of the rant not providing all the data.

simoncion 11y ago
> ...it takes ~3-4 days to test a single configuration and you can't simply change the kernel halfway through. No worries! I've done very-long-running testing before. Moreover, your blog post made it very clear that you're not some n00b with an axe to grind. :) I wonder if it'll take substantially longer than 3->4 days for my systems to complete a test. Guess I'll find out within a few months! :D :D :D > ...I'm nicely surprised by how polite and factual the posts are. Yeah, the btrfs devs strike me as a really nice bunch of folks. Anyway, thanks for the info and the comment! :D