In simple words, logical block size is the unit used by the ‘kernel’ for read/write operations.. Physical block sizes are the ones which ‘disk controllers’ use for read/write operations.
Is there any way to display logical/ physical block sizes in your system?
Yep, there are:
1) Fetch this information from the ‘sysfs’:
‘sda’ is the example device
[terminal]
[root@humbles-lap ]# cat /sys/block/sda/queue/logical_block_size
512
[root@humbles-lap ]# cat /sys/block/sda/queue/physical_block_size
512
[root@humbles-lap ]#
[/terminal]
2) Use ‘blockdev’ command to display the same information.
[terminal]
[root@humbles-lap ]# rpm -qf `which blockdev`
util-linux-XXXX
[root@humbles-lap ]#
–getss get logical block (sector) size
–getpbsz get physical block (sector) size
[root@humbles-lap ]# blockdev –getss /dev/sda
512
[root@humbles-lap ]# blockdev –getpbsz /dev/sda
512
[root@humbles-lap ]#
[/terminal]