Specifications

L LUN number0-7
PP ESS host port number1-32
NNN low-order three characters of the ESS unit serial number or unique
three character value entered using an ESS service panel menu option
4. SCSI-3 attached LUNs emulate the 9337 device type.
5. You can place AS/400 volumes in the ESS storage arrays according to the
selected host system attachment type.
For a SCSI-3 attachment, you must place the volumes in ESS RAID-5 storage
arrays that are common to a single ESS device adapter. You cannot spread the
volumes across arrays that are attached to multiple device adapters.
6. You cannot place AS/400 volumes in an ESS non-RAID storage array.
7. You cannot share an AS/400 volume with two SCSI-3 system attachments.
8. You can use different sizes for AS/400 volumes according to the AS/400 release
level and SCSI-3 attachment type. See Table 11 on page 48 for the supported
volume sizes.
The largest available ESS storage array capacity determines the maximum
volume size you can create.
9. The attachment type and the available ESS storage array capacity determines
the number of volumes that you can create.
You can create1-8volumes for a SCSI-3 attachment.
Recommended configurations for the AS/400
IBM recommends the following configurations:
v Install the feature code 6501 adapter card in the AS/400 system unit or in the I/O
towers.
v Do not use more than two 6501 adapter cards for each AS/400 tower.
9337 subsystem emulation
When attached to an AS/400 host system, the ESS emulates a 9337 subsystem.
The ESS, emulating a 9337, has one unique controller that has as many as eight
disk units (LUNs) attached.
A single feature code 6501, which contains two ports and is attached to an ESS,
supports two emulated 9337s. Feature code 6501 supports 16 LUNs, 8 per port,
and requires two ports with at least one adapter on the ESS. IBM recommends that
you spread the ESS ports across clusters and adapters.
For a real 9337, parity data occupies one-fourth the capacity of each odd numbered
physical drive installed. The total capacity for the parity data is equivalent to one full
physical drive. Four out of eight physical drives have less available capacity to the
AS/400 host system. On the ESS, you can perform the parity function so that all
eight LUNs show a total available capacity for the AS/400.
A real 9337 reports each LUN serial number to the AS/400 host system as a
two-digit physical slot number. The real 9337 also reports the last five digits of the
serial number of the 9337 physical subsystem. The real 9337 appears on the
AS/400 host system as one controller with as many as eight LUNs.
The ESS reports each LUN to the AS/400 host system in the following sequence:
1. A zero (not shown on the AS/400 display)
2. The LUN number
46 ESS Host Systems Attachment Guide
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