About dynamic multi-pathing
In a SAN fabric, it is advantageous (for redundancy reasons) for multiple pathways to exist from a host computer to a device on a disk array. The purpose of dynamic multi-pathing software is the following:
Manage these pathways so that only one is in use at a time
Switch to another pathway if the one in use fails
Snapshot Manager supports EMC PowerPath dynamic multi-pathing software on Solaris and Windows. Due to limitations that prevent the dynamic importing of devices, PowerPath is not supported on Linux.
For certain arrays, Snapshot Manager works in a multipath configuration with or without PowerPath installed, because all visible device paths provide equal access to the array device. EMC Symmetrix and HP-EVA arrays behave in this manner. For other arrays, if multiple device paths exist to an array device, Snapshot Manager can use only one of those paths. In this case, PowerPath must be used to ensure that Snapshot Manager always uses the active device path. EMC CLARiiON behaves in this manner. If PowerPath is not in use and the disk array is EMC CLARiiON, the Fibre Channel switch must be configured so that only one path is zoned to the NetBackup client.
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