IBM DS8700, Introduction And Planning Manual

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v Two device adapter (DA) pairs are required for a business class configuration.
For business class configuration with feature 4211 (16 GB processor memory),
only one DA pair is supported.
Note: Storage features, such as disk enclosures, are installed from the bottom to
the top of each base or expansion model. Filling a model is not required for
you to begin adding storage features to the next model in the storage unit.
Configuration rules for Standby CoD disks
Use the following configuration rules and ordering information to help you order
and activate Standby Capacity On Demand (Standby CoD) disk drive sets.
The following requirements apply:
v
The storage unit in which the Standby CoD disk drives reside must use the IBM
call home feature.
v Each 941 or 94E storage unit can have a maximum of four Standby CoD disk
drive set features that are installed at any one time.
v
Each 951 or 95E storage unit can have a maximum of six Standby CoD disk
drive set features that are installed at any one time.
v You must have twice as many regular disk drive set features installed in the 941
and 94E storage units as there are Standby CoD disk drive set features. For
example, if you order two Standby CoD disk drive set features (48 drives) for a
941 or 94E storage unit, you must have at least four regular disk drive features
(96 drives) on the storage unit.
v You must have three times as many regular disk drive set features installed in
the 951 and 95E storage units as there are Standby CoD disk drive set features.
For example, if you order two Standby CoD disk drive set features (48 drives)
for a 951 or 95E storage unit, you must have at least six regular disk drive
features (144 drives) on the storage unit.
v
If you have one type of Standby CoD disk drive set feature installed, you cannot
order regular disk drive set features of the same type without first activating
(purchasing) the Standby CoD disk drives.
Standby CoD capacity must be activated within one year of purchase. When you
activate Standby CoD capacity, you must order a feature conversion to convert the
Standby CoD disk drive set feature to the corresponding regular disk drive set
feature. You must activate all drives in the Standby CoD disk set at once. Once you
activate Standby CoD disk drive set features, the activation is permanent (once
activated, disk capacity cannot be reduced).
Standby CoD disk drive sets are subject to the same intermix options and
limitations as regular disk drive sets.
Additional storage feature information
To help you determine the type and number of disk drives to add to your storage
unit, this section includes additional information.
The following additional information is provided:
v Calculating physical and effective capacity of disk drives
Calculating physical and effective capacity
Use the following information to calculate the physical and effective capacity of a
storage unit.
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Introduction and Planning Guide