IBM DS8882F, Введение и руководство по планированию

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Configuration rules for storage features
Use the following general configuration rules and ordering information to help you
order storage features.
High Performance Flash Enclosures Gen2
Follow these configuration rules when you order storage features for storage
systems with High Performance Flash Enclosures Gen2.
Flash drive sets
The High Performance Flash Enclosure Gen2 pair requires a minimum of
one 16 flash-drive set.
Storage enclosure fillers
For the High Performance Flash Enclosures Gen2, one filler feature
provides a set of 16 fillers. If only one flash-drive set is ordered, then two
storage enclosure fillers are needed to fill the remaining 32 slots in the
High Performance Flash Enclosures Gen2 pair. If two drive sets are ordered
(32 drives), one filler set is require to fill the remaining 16 slots. Each drive
slot in a High Performance Flash Enclosures Gen2 must have either a flash
drive or a filler.
Physical and effective capacity
Use the following information to calculate the physical and effective capacity of a
storage system.
To calculate the total physical capacity of a storage system, multiply each drive-set
feature by its total physical capacity and sum the values. For High Performance
Flash Enclosures Gen2, there are 16 identical flash drives per drive set, up to three
drive sets per enclosure pair.
The logical configuration of your storage affects the effective capacity of the drive
set.
Specifically, effective capacities vary depending on the following configurations:
RAID type and spares
Drives in the DS8882F must be configured as RAID 5, RAID 6, or RAID 10
arrays before they can be used, and then spare drives are assigned. RAID
10 can offer better performance for selected applications, in particular, high
random, write content applications in the open systems environment.
RAID 6 increases data protection by adding an extra layer of parity over
the RAID 5 implementation.
Data format
Arrays are logically configured and formatted as fixed block (FB) or count
key data (CKD) ranks. Data that is accessed by open systems hosts or
Linux on IBM Z that support Fibre Channel protocol must be logically
configured as FB. Data that is accessed by IBM Z hosts with z/OS or
z/VM must be configured as CKD. Each RAID rank is divided into
equal-sized segments that are known as extents.
The storage administrator has the choice to create extent pools of different
extent sizes. The supported extent sizes for FB volumes are 1 GB or 16 MB
and for CKD volumes it is one 3390 Mod1, which is 1113 cylinders or 21
cylinders. An extent pool cannot have a mix of different extent sizes.
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DS8882F Introduction and Planning Guide