IBM TotalStorage DS6000 Series: Performance Monitoring and Tuning

Chapter 5. Host attachment 145

򐂰 Either fabric or point-to-point topologies

򐂰 A maximum of eight host ports

򐂰 A maximum of 2048 logical paths on each host port

򐂰 Access to all 32 control-unit images (8192 CKD devices) over each FICON port

5.1.3 Example of host attachments

An example of the different host attachment types is shown in Figure 5-1. This example has a

mix of open systems servers and z/OS servers.

Figure 5-1 DS6000 attachment types: FCP and FICON

5.2 Multipathing

For whichever host attachment method you use, we recommend that whenever possible, you

use two or more paths from each FCP or FICON host to the DS6000, and balance the host

connections across both controller cards. For the DS6000, it is important that host systems

have attachment to both controller cards. See 2.3, “DS6000 major hardware components” on

page 19 for details on preferred pathing and why connectivity to both controller cards is

important for the DS6000.

By attaching a host with redundant paths to the DS6000, you can increase

availability by

avoiding single points of failure. Additionally, over and above preferred pathing considerations,

I/O

performance can be improved by configuring multiple physical paths to groups of heavily

Controller

card 0

SAN fabric

Controller

card 1

Power PC

chipset

Power PC

chipset

Persistent memory

Volatile

memory

Persistent memory

Volatile

memory

host adapter

chipset

host adapter

chipset

device adapter

chipset

device adapter

chipset

z-Series

(FICON)

Linux

AIX

Windows

DS6000 Model 511