HP VMA-series Memory Arrays - Manual (Page 86)

86 AM456-9007B Rev 02 HP VMA SAN Gateway Installation and User Guide
vian HP VMA SAN Gateway 2). To a host server, each of these paths appears as a
separate device (for example, /dev/sdb , /dev/sdc , and so on.)
You can configure MPIO on the host servers to aggregate these four devices into a
single device, so that the HA paths appear as a single device. The MPIO driver
balances the load across the paths (devices). If any of the paths should fail, the
remaining paths are used. The path failover is transparent to the user, apart from
possible performance degradation due to fewer paths being used.
Note: Figure 4.5 uses a Linux client and Device Mapper as an example. See
Optimizing Connectivity to Storage Arrays for Windows on page 82 for
information on installing the MPIO driver for Windows.
Non-Disruptive Software Upgrades
In a non-HA configuration, when you upgrade the software on a HP VMA SAN
Gateway, it requires the HP VMA SAN Gateway to be unavailable for a period of
time while the new software is loaded and the HP VMA SAN Gateway is rebooted.
During this time, the data on the HP VMA Array is not available to vSHARE
clients.
Figure 4.5 Mapping Multiple HA Paths to a Single Device Image will need to be redone
HP VMA memory array Memory
Gateway 2
Port B Port A
x4 PCIe
HBA-A1 HBA-A2
x4 PCIe
/dev/mapper/mpath1:
/dev/sdb
/dev/sdc
/dev/sdd
/dev/sde
vSHARE Client
/dev/sdb
/dev/sdc /dev/sdd
/dev/sde
HBA-A1 HBA-A2
Memory
Gateway 1