On 07/23/2013 04:03 PM, Carlos Maiolino wrote:
$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.
The limits 64K and 1G are correct and enforced by the pool constructor
in the target.
Blocksize is _not_ a multiple of 64K; it has to be power of 2.
Thus 64K,128K,256K,512K and 1G are valid block sizes for the pool with
the current pool constructor limits enforced.
-- lvmguy
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
--
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