diff options
Diffstat (limited to 'misc/mke2fs.8.in')
| -rw-r--r-- | misc/mke2fs.8.in | 59 |
1 files changed, 33 insertions, 26 deletions
diff --git a/misc/mke2fs.8.in b/misc/mke2fs.8.in index 1575b089..b02905ba 100644 --- a/misc/mke2fs.8.in +++ b/misc/mke2fs.8.in @@ -267,10 +267,12 @@ are developing test cases. .TP .BI \-G " number-of-groups" Specify the number of block groups that will be packed together to -create one large virtual block group on an ext4 filesystem. This -improves meta-data locality and performance on meta-data heavy -workloads. The number of groups must be a power of 2 and may only be -specified if the flex_bg filesystem feature is enabled. +create a larger virtual block group (or "flex_bg group") in an +ext4 filesystem. This improves meta-data locality and performance +on meta-data heavy workloads. The number of groups must be a power +of 2 and may only be specified if the +.B flex_bg +filesystem feature is enabled. .TP .BI \-i " bytes-per-inode" Specify the bytes/inode ratio. @@ -468,20 +470,27 @@ prefix the feature name with a caret ('^') character. The pseudo-filesystem feature "none" will clear all filesystem features. .RS 1.2i .TP -.B large_file -Filesystem can contain files that are greater than 2GB. (Modern kernels -set this feature automatically when a file > 2GB is created.) -.TP .B dir_index Use hashed b-trees to speed up lookups in large directories. .TP +.B extent +Instead of using the indirect block scheme for storing the location of +data blocks in an inode, use extents instead. This is a much more +efficient encoding which speeds up filesystem access, especially for +large files. +.TP .B filetype Store file type information in directory entries. .TP .B flex_bg -Allow bitmaps and inode tables for a block group to be placed anywhere -on the storage media (use with \-G option to group meta-data in order -to create a large virtual block group). +Allow the per-block group metadata (allocation bitmaps and inode tables) +to be placed anywhere on the storage media. In addition, +.B mke2fs +will place the per-block group metadata together starting at the first +block group of each "flex_bg group". The size of the flex_bg group +can be specified using the +.B \-G +option. .TP .B has_journal Create an ext3 journal (as if using the @@ -496,21 +505,9 @@ option). @JDEV@must be created with the same @JDEV@block size as the filesystems that will be using it. .TP -.B extent -Instead of using the indirect block scheme for storing the location of -data blocks in an inode, use extents instead. This is a much more -efficient encoding which speeds up filesystem access, especially for -large files. -.TP -.B uninit_bg -Create a filesystem without initializing all of the block groups. This -feature also enables checksums and highest-inode-used statistics in each -blockgroup. This feature can -speed up filesystem creation time noticeably (if lazy_itable_init is -enabled), and can also reduce -.BR e2fsck -time dramatically. It is only supported by the ext4 filesystem in -recent Linux kernels. +.B large_file +Filesystem can contain files that are greater than 2GB. (Modern kernels +set this feature automatically when a file > 2GB is created.) .TP .B resize_inode Reserve space so the block group descriptor table may grow in the future. @@ -527,6 +524,16 @@ extended option. .B sparse_super Create a filesystem with fewer superblock backup copies (saves space on large filesystems). +.TP +.B uninit_bg +Create a filesystem without initializing all of the block groups. This +feature also enables checksums and highest-inode-used statistics in each +blockgroup. This feature can +speed up filesystem creation time noticeably (if lazy_itable_init is +enabled), and can also reduce +.BR e2fsck +time dramatically. It is only supported by the ext4 filesystem in +recent Linux kernels. .RE .TP .B \-q |