On Fri, Jul 23, 2021 at 05:30:13PM +0200, Mikhail Morfikov wrote: > In the man ext4(5) we can read the following: > > Warning: The bigalloc feature is still under development, > and may not be fully supported with your kernel or may > have various bugs. Please see the web page > http://ext4.wiki.kernel.org/index.php/Bigalloc for details. > May clash with delayed allocation (see nodelalloc mount > option). > > According to the link above, the info is dated back to 2013, > which is a little bit ancient. > > What's the current status of the feature? Is it safe to use > bigalloc on several TiB hard disks where only big files will be > stored? Yes; the places where bigalloc is perhaps not as well tested is support FALLOC_FL_COLLAPSE_RANGE, FALLOC_FL_INSERT_RANGE, and FALLOC_FL_PUNCH_HOLE. Bigalloc is also not very efficient for large directories (where we allocate a full cluster for each directory block). Older kernels did not handle ENOSPC errors when delayed allocation was enabled, but that has since been fixed, and bigalloc is passing file system regression tests, so it should safe to use as you've described. Cheers, - Ted
