$data_block_size can't be any arbitrary number, i.e. its value should be between 64K and 1G. Also, it should be a multiple of 64K. Add this information to the dm-thin documentation in order to let users know which values they must use. Signed-off-by: Carlos Maiolino <cmaiolino@xxxxxxxxxx> --- Documentation/device-mapper/thin-provisioning.txt | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/Documentation/device-mapper/thin-provisioning.txt b/Documentation/device-mapper/thin-provisioning.txt index 30b8b83..ff1629b 100644 --- a/Documentation/device-mapper/thin-provisioning.txt +++ b/Documentation/device-mapper/thin-provisioning.txt @@ -104,8 +104,8 @@ primarily interested in thin provisioning may want to use a value such as 1024 (512KB). People doing lots of snapshotting may want a smaller value such as 128 (64KB). If you are not zeroing newly-allocated data, a larger $data_block_size in the region of 256000 (128MB) is suggested. -$data_block_size must be the same for the lifetime of the -metadata device. +$data_block_size must be between 128 (64KB) and 2097152 (1GB) and be a multiple +of 128 (64KB), and the same for the lifetime of the metadata device. $low_water_mark is expressed in blocks of size $data_block_size. If free space on the data device drops below this level then a dm event -- 1.8.1.4 -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
