HP Surestore Disk Array 12h and FC60 User Manual
Page 210
210 Verifying Disk Array Connection
VSA is an enhancement that increases the number of LUNs that can be addressed on a fibre
channel disk array to 16382 (2
14
). This compares with the 8 LUN limit imposed by PDA. The
HP SureStore E Disk Array FC60 requires that 32 LUNs (0 - 31) be addressable.
To implement VSA, the fibre channel driver creates four virtual SCSI busses, each capable
of supporting up to eight LUNs. Each virtual SCSI bus supports the following LUNs:
The LUNs for each virtual SCSI bus are numbered 0 - 7, but reflect the LUN numbers
assigned to each bus. For example, LUN 0 on virtual SCSI bus 2 is really LUN 16 on the disk
array.
The virtual SCSI bus is identified by the next-to-last segment of the hardware path. For
example, in the following ioscan entry, the value identifying virtual SCSI bus 1 is shown in
bold.
shows all four virtual SCSI bus entries for a disk array.
disk 4 8/8.8.0.0.0.
1
.0 sdisk CLAIMED DEVICE HP A5277A
/dev/dsk/c9t1d0 /dev/rdsk/c9t1d0
Why Are There ioscan Entries for LUNs I Didn’t Bind?
By default, an ioscan entry is made for LUN 0 of each virtual SCSI bus. This does not imply
that there is an actual LUN 0 bound on the disk array. To determine if there is a LUN on the
bus, use the
diskinfo
command.
For example, the sample entry above is for LUN 0 on virtual SCSI bus 1, or LUN 8. To
determine if there is a LUN on virtual SCSI bus 1, perform a
diskinfo
command on the
raw device file for that entry as follows:
diskinfo /dev/rdsk/c9t1d0
Virtual SCSI
Bus
Supported LUNs
0
0 - 7
1
8 - 15
2
16 - 23
3
24 - 31