On 04-Jan-99 Zdenek Salvet spoke unto us all:
# > alice# ccdconfig -g
# > ccd0            125     0       /dev/sd0b /dev/sd1b
#                   ^^^^^
#  Multiple of your filesystem's block size may be better - e.g. 64 or 128 .

actually...

# > sd0 at scsibus0 targ 0 lun 0: <IBM, DDRS-34560W, S97B> SCSI2 0/direct fixed
# > sd0: 4357MB, 8387 cyl, 5 head, 212 sec, 512 bytes/sect x 8925000 sectors
# > sd1 at scsibus0 targ 1 lun 0: <IBM, DDRS-34560W, S97B> SCSI2 0/direct fixed
# > sd1: 4357MB, 8387 cyl, 5 head, 212 sec, 512 bytes/sect x 8925000 sectors

I did an expirament one day with my sparc, and 3 of the exact same disk.  I
wrote a perl script to reconfigure the ccd with every possible number between 1
and like 800, and find the fastest combination..  it eventually picked 158.  

sd2 at scsibus0 targ 2 lun 0: <IBM, CFA170S       !S, 167A> SCSI2 0/direct fixed
sd2: 163MB, 2111 cyl, 2 head, 79 sec, 512 bytes/sect x 335270 sectors

Hrmmm.. notice, 2 heads, 79 sectors..  2 * 79 == 158

It may definately pay to fiddle around with different values.. but my findings
were that with those particular disks, 158 was by far the fastest.

---
Tim Rightnour  -  root@garbled.net
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