Order of sd# allocation on isp fibre channel card

["Scott Burns" <Scott.Burns%SeQent.Com@localhost>]

I have a HP DL380/G6 with NetBSD/amd64 6.1.4.

1 x QLogic QLE2562 8Gb dual port fibre channel card (HP Version)
1 x HP M6412A 12 drive enclosure
12 x HP 450GB fibre channel drives

Strangely the sd# are allocated starting at the 5th (sd2) drive in the
enclosure. They then continue sequentially until the 12th (sd9) drive and
then wrap around and continue from drive 1 (sd10) - 4 (sd13).

The target #'s are sequential as shown in the dmesg snippet below.

Is there a logic behind how this is done? At first I thought maybe there was
a MAC address on each drive and it was in sequential order but the luck of
installing them perfectly in sequence doesn't make any sense.

1) Can I assume this will stay static? It has across many reboots so far.
- I am about to add another M6412A enclosure on the 2nd port with another 12
drives.

2) Does anyone know the logic behind how the sd# drives are allocated for
this controller?

3) I know I can map these directly to targets in the kernel config file but
I am wondering if the odd allocation of target numbers starting at the 5th
drive in the enclosure is a constant.

dmesg below......

scsibus2 at isp0: 512 targets, 8 luns per target
scsibus3 at isp1: 512 targets, 8 luns per target

sd2 at scsibus2 target 0 lun 0: <HPQ, BF450DA483, HP06> disk fixed
sd2: 419 GB, 153352 cyl, 8 head, 716 sec, 512 bytes/sect x 878906250 sectors
sd3 at scsibus2 target 1 lun 0: <HPQ, BF450DA483, HP06> disk fixed
sd3: 419 GB, 153352 cyl, 8 head, 716 sec, 512 bytes/sect x 878906250 sectors
sd4 at scsibus2 target 2 lun 0: <HPQ, BF450DA483, HP06> disk fixed
sd4: 419 GB, 153352 cyl, 8 head, 716 sec, 512 bytes/sect x 878906250 sectors
sd5 at scsibus2 target 3 lun 0: <HPQ, BF450DA483, HP06> disk fixed
sd5: 419 GB, 153352 cyl, 8 head, 716 sec, 512 bytes/sect x 878906250 sectors
sd6 at scsibus2 target 4 lun 0: <HPQ, BF450DA483, HP06> disk fixed
sd6: 419 GB, 153352 cyl, 8 head, 716 sec, 512 bytes/sect x 878906250 sectors
sd7 at scsibus2 target 5 lun 0: <HPQ, BF450DA483, HP06> disk fixed
sd7: 419 GB, 153352 cyl, 8 head, 716 sec, 512 bytes/sect x 878906250 sectors
sd8 at scsibus2 target 6 lun 0: <HPQ, BF450DA483, HP06> disk fixed
sd8: 419 GB, 153352 cyl, 8 head, 716 sec, 512 bytes/sect x 878906250 sectors
sd9 at scsibus2 target 7 lun 0: <HPQ, BF450DA483, HP06> disk fixed
sd9: 419 GB, 153352 cyl, 8 head, 716 sec, 512 bytes/sect x 878906250 sectors
sd10 at scsibus2 target 9 lun 0: <HPQ, BF450DA483, HP06> disk fixed
sd10: 419 GB, 153352 cyl, 8 head, 716 sec, 512 bytes/sect x 878906250
sectors
sd11 at scsibus2 target 10 lun 0: <HPQ, BF450DA483, HP06> disk fixed
sd11: 419 GB, 153352 cyl, 8 head, 716 sec, 512 bytes/sect x 878906250
sectors
sd12 at scsibus2 target 11 lun 0: <HPQ, BF450DA483, HP06> disk fixed
sd12: 419 GB, 153352 cyl, 8 head, 716 sec, 512 bytes/sect x 878906250
sectors
sd13 at scsibus2 target 12 lun 0: <HPQ, BF450DA483, HP06> disk fixed
sd13: 419 GB, 153352 cyl, 8 head, 716 sec, 512 bytes/sect x 878906250
sectors


Thank you
Scott...