7914DS3KPlanning_090710.fm Draft Document for Review March 28, 2011 12:24 pm
32 IBM System Storage DS3500: Introduction and Implementation Guide
Zoning with MPIO
MPIO is a multipath driver which provides for a host to be able to recognize multiple paths to
the attached storage device. This is done by utilizing multiple HBA ports or devices within the
host server connected to SAN fabric switches, which are also connected to the multiple ports
on the storage devices. For the storage products referred to as DS3000, DS4000, or DS5000,
these devices have two controllers within the subsystem that manage and control the disk
drives. These controllers behave in an active/passive fashion. Ownership and control of a
particular LUN is done by one controller. The other controller is in a passive mode until a
failure occurs, at which time the LUN ownership is transferred to that controller. Each
controller may have more than one fabric port for connectivity to the SAN fabric. This helps to
provide faster recovery for path failures that can be resolved through the use of an alternate
connection to the same controller verses requiring the full failover process be ran.
The DS3500 models only support drivers that by design follow the rules for this type of path
management. See Figure 3-1 for an example of how the configuration should be
implemented.
Figure 3-1 Host HBA to storage subsystem controller multipath sample configuration
With MPIO, it is better to create a zone for each HBA port to be able to see both controllers to
help decrease failover operations for network related failures. In the above example to do this
you would create zones for the three host servers (two zones each) with one being from HBA
port 1 to both controller A port 1 and controller B port 1 of the DS3500 storage server, and the
Important: Disk and tape must be on separate HBAs, following the best practice for
zoning; then the disk and tape access will also be in separate zones. With certain UNIXÂŽ
systems, this arrangement is supported by the DS3500 Storage System, but might have
hardware limitations; therefore,
do not share HBAs between disk storage and tape.
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