Specifications

on the AIX server for each physical LUN. If you create a PVID sector 0 of a LUN
and you delete all hdisks from the system with the rmdev command, you must
restart the system. If you want to restore all multiple paths for all LUNs, use the
cfgmgr command for each SCSI adapter.
Emulating UNIX-based host systems
For UNIX-based host systems, the ESS emulates multiple SCSI DDMs. The host
system accesses the virtual drives of the ESS as if they were generic SCSI DDMs.
The AIX operating system contains entries in its object distribution manager
database to identify the ESS. However, the AIX operating system accesses the ESS
through its generic SCSI DDMs.
The ESS appears as a standard physical volume or hdisk to AIX, Solaris, and
HP-UX systems.
When you use ultra- or wide-SCSI adapters in your host systems, a total of 16
SCSI IDs per interface is available on the ESS. The host system SCSI IDs are
known as initiators; the ESS SCSI IDs are the targets.
If only one host system connects to an ESS SCSI port, the ESS can assign up to
15 unique target IDs. If the maximum of four host systems are connected to an
ESS SCSI port, the ESS assigns up to 12 unique SCSI target IDs because each
host uses one SCSI ID.
You can configure an ESS to appear as 64 LUNs per SCSI target. The ESS
supports LUN sizes from 100 MB up to 100 MB x n where n equals 1 to 2455
(245.5 GB). You can increase LUN sizes in 100 MB increments.
Note: LUN usage is limited for some host systems. See Table 6 on page 11.
Table 15. Size of drives, configurations, and maximum size of LUNs
Size of
Drives Configuration
Maximum Size of
LUNs
9.1 GB 6 + P array Model E10, E20, F10, or F20 52.5
9.1 GB 7 + P array Expansion enclosure for Model E20 61.3
18.2 GB 6 + P array Model E10, E20, F10 or F20 105.2
18.2 GB 7 + P array Expansion enclosure for Model E20 122.7
36.4 GB 6 + P array Model E10, E20, F10, or F20 210.4
36.4 GB 7 + P array Expansion enclosure for Model E20 245.5
Attaching with fibre-channel adapters
This section describes the host system requirements and provides the procedures
to attach an ESS to the following host systems::
v RS/6000
v pSeries
v RS/6000 Series Parallel (SP) Complex
v pSeries SP Complex
Note: For an RS/6000 or pSeries host system, you can use either of the following
topologies:
60 ESS Host Systems Attachment Guide