From 86800f5d75abd05e12de0b2e1ebd48f049cf256a Mon Sep 17 00:00:00 2001 From: Karel Zak Date: Thu, 2 Mar 2017 13:44:26 +0100 Subject: sfdisk: add note about alignment to man page Addresses: https://github.com/karelzak/util-linux/issues/417 Signed-off-by: Karel Zak --- disk-utils/sfdisk.8 | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) (limited to 'disk-utils/sfdisk.8') diff --git a/disk-utils/sfdisk.8 b/disk-utils/sfdisk.8 index e8ecf4838..b72bb3217 100644 --- a/disk-utils/sfdisk.8 +++ b/disk-utils/sfdisk.8 @@ -35,9 +35,20 @@ never been important for Linux, and this addressing concept does not make any sense for new devices. .sp .B sfdisk -(since version 2.26) aligns the start and end of partitions to -block-device I/O limits when relative sizes are specified, or when the -default values are used. +(since version 2.26) +.B aligns the start and end of partitions +to block-device I/O limits when relative sizes are specified, when the default +values are used or when multiplicative suffixes (e.g MiB) are used for sizes. +It is possible that partition size will be optimized (reduced or enlarged) due +to alignment if the start offset is specified exactly in sectors and partition +size relative or by multiplicative suffixes. + +The recommended way is not to specify start offsets at all and specify +partition size in MiB, GiB (or so). In this case sfdisk align all partitions +to block-device I/O limits (or when I/O limits are too small then to megabyte +boundary to keep disk layout portable). If this default behaviour is unwanted +then specify offsets and sizes in sectors. In this case sfdisk entirely +follows specified numbers without any optimization. .sp .B sfdisk does not create the standard system partitions for SGI and SUN disk labels like -- cgit v1.2.3-55-g7522