blocksize question

[Eyal Lebedinsky <eyal@xxxxxxxxxxxxxx>]

We have an 8 disk RAID-5 on 3ware setup at the office. The whole
disk (/dev/sda) is xfs.

We notice that the performance is not that hot, and one thing
we are looking at is the block size. XFS says it is 4096:

=======================================
[root@ssa18 ~]# xfs_info /backup
meta-data=/backup                isize=256    agcount=268,
agsize=1048576 blks
         =                       sectsz=512
data     =                       bsize=4096   blocks=280149632,
imaxpct=25
         =                       sunit=0      swidth=0 blks, unwritten=1
naming   =version 2              bsize=4096
log      =internal               bsize=4096   blocks=32768, version=1
         =                       sectsz=512   sunit=0 blks
realtime =none                   extsz=65536  blocks=0, rtextents=0
=======================================

At the same time we see:

=======================================
[root@ssa18 ~]# blockdev --getbsz /dev/sda
512
=======================================

Is this how it is supposed to be?

--
Eyal Lebedinsky (eyal@xxxxxxxxxxxxxx) <http://samba.org/eyal/>