Dual-Controller Configurations; Connecting Hosts: S3200 Direct Attach-One Server/One Hba/Dual Path; Connecting Hosts: S2200 Direct Attach-One Server/One Hba/Dual Path - Lenovo S3200 Setup Manual

See the "Replacing a controller or expansion module" topic within the CRU Installation and Replacement
Guide for additional information about installing IOMs.

Dual-controller configurations

A dual-controller configuration improves application availability because in the event of a controller failure,
the affected controller fails over to the partner controller with little interruption to data flow. A failed
controller can be replaced without the need to shut down the storage system.
In a dual-controller system, hosts use LUN-identifying information from both controllers to determine that up
to four paths are available to a given storage volume. Assuming MPIO software is installed, a host can use
any available data path to access a volume owned by either controller. The path providing the best
performance is through host ports on the volume's owning controller. Both controllers share one set of
1,024 LUNs (0- 1 ,023) for use in mapping volumes to hosts (see "ULP" in the Storage Manager Guide).
The illustrations below show dual-controller configurations for S3200/S2200 controller enclosures
equipped with either CNC ports or 12 Gb HD mini-SAS host ports.
One server/one HBA/dual path
S3200 CNC
S3200 SAS
Figure 20 Connecting hosts: S3200 direct attach—one server/one HBA/dual path
S2200 CNC
S2200 SAS
Figure 21 Connecting hosts: S2200 direct attach—one server/one HBA/dual path
Server
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Lenovo Storage S3200/S2200 Setup Guide
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