Users Guide

Figure 11. PERC H840 card ports—Eight enclosures with single path configuration
To set up a single path enclosure on the PERC H840 card:
1. To connect a single enclosure, cable the ports so that the enclosure is connected to both the ports on the controller card.
2. To connect multiple enclosures, single cables connect the first enclosure to the second enclosure, then the single cable
connects the second enclosure to the third enclosure.
NOTE:
You must use a PD240 profile to support 4 enclosures per port. For more information, see Profile Management on
page 22.
Redundant path support for PERC H840
The PERC H840 adapter can detect and use redundant paths to disks contained in enclosures. This provides the ability to
connect two SAS cables between a controller and an enclosure for path redundancy. The controller can tolerate the failure of a
cable or enclosure management module (EMM) by utilizing the remaining path. When redundant paths exist, the controller
automatically balances I/O loads through both paths to each disk. Load balancing increases throughput to virtual disks in
storage enclosures and is automatically turned on when redundant paths are detected. To set up your hardware to support
redundant paths, see Setting up redundant path support on the PERC H840 adapter.
NOTE: This is applicable for the PERC H840 only.
NOTE: This support for redundant paths refers to path redundancy only and not to controller redundancy.
Features 21