Advanced POWER Virtualization on IBM System p5 - Previous ...

Summary of HA alternatives for access to external networks
Table 4-2 summarizes the alternative approaches to achieve high-availability for
shared access to external networks that have been discussed in the previous
sections.
Table 4-2 Summary of HA alternatives for access to external networks
Server-implementation
Client-implementation
Layer-2 / bridged SEA Failover NIB
Layer-3 / routed Router failover IPMP, VIPA, and IPAT
Of these approaches, the new SEA Failover feature is the most appropriate in
typical IBM System p5 virtualization scenarios, so we will focus on SEA Failover
in the rest of this redbook. You should refer to additional publications if you
consider implementing one of the other alternatives.
4.1.4 System management with Virtual I/O Server
Redundancy allows for easier system management, such as software upgrades.
With two Virtual I/O Servers, the layer of physical resource dependency has been
removed.
System maintenance can now be performed on a Virtual I/O Server and any
external device it connects to, such as a network or SAN switch. With virtual
SCSI and shared Ethernet being hosted by a second Virtual I/O Server,
rebooting or disconnecting the Virtual I/O Server from its external devices is now
possible without causing client outages. With the client partition running MPIO
and using SEA Failover, no actions will need to be performed on the client
partition while the system maintenance is being performed or after it has
completed. This results in improved uptime and reduced system administration
efforts for the client partitions.
Upgrading and rebooting a Virtual I/O Server, network switch, or SAN switch is
simpler and more compartmentalized, since the client is no longer dependant on
the availability of all of the environment.
Chapter 4. Setting up virtual I/O: advanced 199