diff options
Diffstat (limited to 'disk-utils/mkswap.8')
| -rw-r--r-- | disk-utils/mkswap.8 | 17 |
1 files changed, 9 insertions, 8 deletions
diff --git a/disk-utils/mkswap.8 b/disk-utils/mkswap.8 index 27f922171..bdc631491 100644 --- a/disk-utils/mkswap.8 +++ b/disk-utils/mkswap.8 @@ -130,17 +130,18 @@ e.g.\& using a command like to create 8GiB swapfile. -Note that a swap file must not contain any holes. Using +The swap file implementation in the kernel expects to be able to write to the file directly, +without the assistance of the filesystem. This is a problem on files with holes +(e.g. created by .BR cp (1) -to create the file is not acceptable. Neither is use of -.BR fallocate (1) -on file systems that support preallocated files, such as -.BR XFS " or " ext4 , -or on copy-on-write filesystems like +or another commands), or on files on copy-on-write filesystems like .BR btrfs . -It is recommended to use +In some cases preallocated files (e.g. fallocate(1) on XFS) maybe interpreted +by kernel as files with holes too. The most portable solution is to use .BR dd (1) -and /dev/zero in these cases. Please read notes from +and /dev/zero in these cases. +.sp +Please read notes from .BR swapon (8) before adding a swap file to copy-on-write filesystems. |