https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=204929
Bug ID: 204929 Summary: fs_optim and fs_minfree default value is 10% in man fs(5),while newfs(8),tunefs(8) is 8% Product: Documentation Version: Latest Hardware: amd64 OS: Any Status: New Severity: Affects Some People Priority: --- Component: Documentation Assignee: freebsd-doc@FreeBSD.org Reporter: am...@amutu.com this from fs(5): The fs_minfree element gives the minimum acceptable percentage of file system blocks that may be free. If the freelist drops below this level only the super-user may continue to allocate blocks. The fs_minfree ele‐ ment may be set to 0 if no reserve of free blocks is deemed necessary, however severe performance degradations will be observed if the file sys‐ tem is run at greater than 90% full; thus the default value of fs_minfree is 10%. The element fs_optim specifies whether the file system should try to min‐ imize the time spent allocating blocks, or if it should attempt to mini‐ mize the space fragmentation on the disk. If the value of fs_minfree (see above) is less than 10%, then the file system defaults to optimizing for space to avoid running out of full sized blocks. If the value of minfree is greater than or equal to 10%, fragmentation is unlikely to be problematical, and the file system defaults to optimizing for time. this from newfs(8): -m free-space The percentage of space reserved from normal users; the minimum free space threshold. The default value used is defined by MINFREE from <ufs/ffs/fs.h>, currently 8%. See tunefs(8) for more details on how to set this option. -o optimization (space or time). The file system can either be instructed to try to minimize the time spent allocating blocks, or to try to mini‐ mize the space fragmentation on the disk. If the value of min‐ free (see above) is less than 8%, the default is to optimize for space; if the value of minfree is greater than or equal to 8%, the default is to optimize for time. See tunefs(8) for more details on how to set this option. this from tunefs: -m minfree Specify the percentage of space held back from normal users; the minimum free space threshold. The default value used is 8%. Note that lowering the threshold can adversely affect perfor‐ mance: · Settings of 5% and less force space optimization to always be used which will greatly increase the overhead for file writes. · The file system's ability to avoid fragmentation will be reduced when the total free space, including the reserve, drops below 15%. As free space approaches zero, throughput can degrade by up to a factor of three over the performance obtained at a 10% threshold. If the value is raised above the current usage level, users will be unable to allocate files until enough files have been deleted to get under the higher threshold. -- You are receiving this mail because: You are the assignee for the bug. _______________________________________________ freebsd-doc@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-doc To unsubscribe, send any mail to "freebsd-doc-unsubscr...@freebsd.org"