368 iSeries and AS/400e System Builder
9.5 External tape rules for iSeries and AS/400e systems
9.5.1 High workload placement rules for magnetic media IOP
SPD disk unit, tape, and some LAN IOPs are considered high workload IOPs. Therefore, they
require special consideration when configuring an iSeries or AS/400e system. In addition,
their workload capability IOPs can be streaming or non-streaming. The following table lists
the high workload SPD magnetic media IOPs. It identifies the bus capacity as streaming or
non-streaming. These guidelines are for all system buses including the first system bus
(bus 1). Exceeding these guidelines causes performance degradation.
9.5.2 3590 and disk IOP restriction
From OS/400 V4R1 onward, the 3590 can be placed on any bus as an alternate installation
device. For maximum performance, controllers that drive high-speed tapes must not be
installed in bus extension units (#5060, #5040).
9.5.3 Alternate IPL or alternate installation device
Throughout this book and the IBM eServer i5 and iSeries System Handbook, GA19-5486, the
term
alternate IPL or ALT-IPL is used to describe both alternate IPL devices and alternate
installation devices. It is important to understand the differences. An alternate IPL device
must be attached to the first system bus (bus one), and an alternate installation device can be
attached to any bus except bus one.
Alternate installation device support allows you to perform installation and recovery
procedures using a combination of devices. Prior to V4R1, these types of activities can only
be performed using devices attached to the first system bus. The first system bus connects to
the service processor IOP. Typically, this is where the optical device or tape devices used for
installations are attached. From OS/400 V4R1 onward, you can use a combination of devices
that are attached on the first system bus and on additional buses. The alternate installation
device is not attached to the first system bus.
Subsystem High workload IOP Bus capacity
DASD #6112, #6500 Non-streaming
Tape #2621, #2624, #2644, #6112 Non-streaming
DASD #6501 Tape/Disk Device Controller, #6530, #6502, #6512, #6532, #6533 Streaming
Tape #6501 Tape/Disk Device Controller, #6513, #6534 Magnetic Media Controller Streaming
Tape IOP
with 3590
#6501 Tape/Disk Device Controller, #6534 Magnetic Media Controller Streaming
Optical #6534 Magnetic Media Controller Streaming
LAN #2810 LAN/WAN IOP Streaming
IOP combination limitations:
There is a maximum of five high workload IOPs per bus. This includes system bus 1.
There is a maximum of three non-streaming high workload IOPs per bus.
In #5044 System Unit Expansion Rack, no DASD controllers are allowed on the same bus with a 3590 tape
controller. More than one 3590 tape controller is allowed on the same bus.
