1.Get the alignment parameters for your array (remember to replace sdb with the name of your device as seen by the kernel).
# cat /sys/block/sdb/queue/optimal_io_size 1048576 # cat /sys/block/sdb/queue/minimum_io_size 262144 # cat /sys/block/sdb/alignment_offset 0 # cat /sys/block/sdb/queue/physical_block_size 512
2.Add optimal_io_size to alignment_offset and divide the result by physical_block_size. In my case this was (1048576 + 0) / 512 = 2048. 3.This number is the sector at which the partition should start. Your new parted command should look like
mkpart primary 2048s 100%
The trailing 's' is important: it tells parted that you’re talking about sectors, not bytes or megabytes.
4.If all went well, the partition will have been created with no warnings. You can check the alignment thusly (replacing '1' with the partition number if necessary):
(parted) align-check optimal 1 1 aligned