Specifications

www.ibm.com/support/techdocs 17

Summary of Best Practices for Storage Area Networks

• Ensure that you have an equal number of extent pools and volumes, equally

spread on the Disk Adapters and the two servers of the DS8000 storage

subsystem.

• Ensure that managed disk groups contain managed disks with similar

characteristics and approximately the same capacity. Consider the following

factors:

 The number of DDMs in the array site (for example 6 + P + S or 7 + P)

and the physical disk type (for example, 10K/15K rpm).

 The underlying RAID type that the DS8000 storage subsystem is using

to implement the managed disk.

• Same disks capacity provides efficient use of the SVC striping.

• Do not mix managed disks of greatly differing performance in the same

managed disk group. The overall group performance will be limited by the

slowest managed disk in the group. Some disk controllers may be able to

sustain much higher I/O bandwidths than others, do not mix managed disks

from low-end subsystems with managed disks from high-end subsystems.

Best practice guidelines dictate that a storage port should be segregated such that

only one of the following is connected to a given port:

• Single SVC cluster

• Hosts

• Mirroring connection to another DS8300

HA oversubscription

Each of the two IO port pairs per storage system host adapter (0/1 and 2/3) should

be split between the redundant fabrics to minimize the impact to storage traffic as a

result of a fabric-wide issue or failure of an individual host adapter in the storage

system.