IBM System storage DS6000 Series, Руководство по присоединению

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Attaching to a FICON channel on a S/390 or zSeries host
This topic describes attaching to a FICON channel on a S/390 or zSeries host.
You can use either longwave or shortwave adapters with the IBM S/390 or zSeries
host systems. The adapter for the IBM S/390 has one channel port. The adapter for
the zSeries has two or four channel ports.
You can attach the FICON channels directly to a storage unit or you can attach the
FICON channels to a fibre-channel switch. When you attach the FICON channels
directly to a storage unit, the maximum number of FICON attachments is 16.
Sixteen is the maximum number of host adapters you can configure in a storage
unit. When you use a storage unit host adapter to attach to FICON channels either
directly or through a switch, the adapter is dedicated to FICON attachment. It
cannot be simultaneously attached to fibre-channel protocol hosts.
When you attach a storage unit to FICON channels through one or more switches,
the maximum number of FICON attachments is 128 per storage unit adapter. The
directors provide very high availability with redundant components and no single
points of failure or repair.
You can use the IBM 2042 Model 001 (CNT 64-port director) or IBM 2042 Model
128 (CNT 128-port director). You can use either director to attach fibre-channel
protocol hosts and devices in addition to the FICON hosts and devices. For these
configurations, the fibre-channel protocol hosts should communicate only with the
fibre-channel protocol devices. The FICON hosts should communicate only with the
FICON devices. Set up zones in the directors to guarantee that none of the
fibre-channel protocol hosts or devices can affect the FICON traffic.
When you attach FICON products to switches or directors, you cannot use
cascaded switches on S/390 host systems and on zSeries 800 and 900 model
systems without licensed internal code (LIC) patches. You cannot configure a fabric
of multiple interconnected directors and have a FICON channel that is attached to
one director communicate to a FICON control unit that is attached to another
director. The FICON architecture prohibits this capability. The reason for the
restriction is because the base S/390 and zSeries I/O architecture uses a single
byte for addressing the I/O devices. This one-byte I/O address is not compatible
with the fibre-channel, 3-byte port address. The FICON solution to this problem on
these host systems is to disallow switch cascading.
However, you can use cascaded switches on zSeries 800 and 900 model host
systems with LIC patches installed and on all other zSeries models. To support
cascaded switches, the fabric must be what is generally called a high integrity
fabric. A high integrity fabric ensures data integrity by detecting any miscabling
within a FICON cascaded switch fabric that could lead to I/O data being delivered to
the wrong destination. A high integrity fabric is one that both supports and is
configured to use fabric-binding and insistent domain IDs. Fabric-binding is the
ability of the fabric to prevent another switch from being added operationally to the
fabric without the new switch being properly planned for in the fabric and for the
switch to be configured with the high integrity attributes. An insistent domain ID is a
function of the fabric that does not allow the switch address to be automatically
changed when a duplicate switch address is added to the fabric. Instead, fabrics
that use insistent domain IDs require an operator’s overt action to change a switch
address. The customization of fabric-binding and the setting of an insistent domain
ID are normally done only at switch installation time or reinstallation time.
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DS6000 Host Systems Attachment Guide