Dell POWERVAULT MD3620I - Manual (Page 107)

Configuration: About Your Host 107
I/O Data Path Protection
You can have multiple host-to-array connections for a host. Ensure that you
select all the connections to the array when configuring host access to the
storage array.
NOTE: See the Deployment Guide for more information on cabling configurations.
NOTE: For more information on configuring hosts see "Configuration: About Your
Host" on page 99.
If a component such as a RAID controller module or a cable fails, or an error
occurs on the data path to the preferred RAID controller module, the virtual
disk ownership is moved to the alternate non preferred RAID controller
module for processing. This failure or error is called failover.
Drivers for multi-path frameworks such as Microsoft Multi-Path IO (MPIO)
and Linux Device Mapper (DM) are installed on host systems that access the
storage array and provide I/O path failover.
For more information on Linux DM, see "Configuration: Device Mapper
Multipath for Linux" on page 195. For more information on MPIO, see
microsoft.com.
NOTE: You must have the multi-path driver installed on the hosts at all times, even
in a configuration where there is only one path to the storage system, such as a
single port cluster configuration.
During a failover, the virtual disk transfer is logged as a critical event, and an
alert notification is sent automatically if you have configured alert
destinations for the storage array.
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