Chris Murphy posted on Sun, 11 Sep 2016 21:03:04 -0600 as excerpted: > The man page says: > "The recommended size for the mixed mode is for filesystems less than > 1GiB." But in this case recommended !=default which requires some mental > gymnastics to rectify. If mixed-bg becomes obsolete upon enospc being no > more likely with isolated block groups, then OK fine, but in the > meantime...
On the bright side, the double-whammy of being under such tight filesystem size constraints, coupled with finding out you have less than half the space of the filesystem actually available due to default-mixed- mode AND default dup-metadata (thus dup everything), gets eliminated, and barring problems with unbalanced chunk-sizes, you actually get to use most of capacity of the filesystem for actual files, instead of less than half of it. =:^) But I remain unconvinced that benefit outweighs the serious administrative headaches trying to run without mixed-mode on such small btrfs is likely to generate. And what's worse, it's the same folks that are likely to have problems coping with either issue, but fixing the under-half-available-for-use (at the cost of filesystem resiliency) is a one-time thing, while the administrative issue of unbalanced chunks is likely to come back to bite them again and again. But still, having people find they can fit only ~110 MiB in a 256 MiB btrfs, while with ext*, they can fit say 240 MiB in the same size filesystem, could be a bit more to try to explain to the technically under-literate, than the devs decided they were willing to deal with. Just saying it'd divided in chunks and another chunk won't fit is arguably easier than trying to explain why the filesystem will fit less than half of what the size of it suggests it should fit, IOW. And I think that argument /was/ made, to some extent. But the whole thing only came up because they found testing with small filesystems inconvenient due to the mixed-bg default, so rather than fix that by fixing the tests, they broke the previously sane defaults, instead. -- Duncan - List replies preferred. No HTML msgs. "Every nonfree program has a lord, a master -- and if you use the program, he is your master." Richard Stallman -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
