Proper swidth and sunit for RAID 5 (does it matter)?

[Justin Piszcz <jpiszcz@xxxxxxxxxxxxxxx>]

Dave,

What is the proper sunit and swidth for a 64, 256, and 1024 kilobyte chunk 
size with a 10-disk raid 5?
Also, in the majority of benchmarks it does not seem to matter whether the 
FS is stripe-aligned or not (with SW raid)- does it mainly/only affect HW 
raid?
Current settings (10 disks):

# xfs_info /dev/md3
meta-data=/dev/md3               isize=256    agcount=4, agsize=82417536 
blks
         =                       sectsz=4096  attr=2
data     =                       bsize=4096   blocks=329670144, imaxpct=25
         =                       sunit=0      swidth=0 blks, unwritten=1
naming   =version 2              bsize=4096
log      =internal               bsize=4096   blocks=32768, version=2
         =                       sectsz=4096  sunit=1 blks, lazy-count=1
realtime =none                   extsz=9437184 blocks=0, rtextents=0

Justin.