Hitachi Compute Blade 500 Series Function Manual page 33

Load Balancing functions contains Fault Tolerance on condition that Load
Balancing is set to a team consisting of LAN devices with the same speed.
When composing a team of Fault Tolerance or Switch Fault Tolerance, select
two LAN devices.
For Load Balancing, up to two LAN devices can form a team in this system
equipment.
It may take a bit longer until the setting is completed.
When selecting three or more LAN devices to team up, Switch Fault Tolerance
is not displayed.
Intel PROSet is used to improve reliability of communication by creating
redundancy to LAN devices. In some environments (network structure or
application), however, it may take from a dozen seconds to a couple of
minutes to restore communication at switching links.
Since incoming data are processed by a single LAN device, the bandwidth
does not change when receiving data. ALB is a function used to improve the
actual throughput with the load balancing function. In some operation
environments such as CPU loading or contents of communication, however, it
may not improve performance due to overhead on the load balance
processing.
LAN devices used in this server blade support four functions only: Adapter
Fault Tolerance, Adaptive Load Balancing, and Switch Fault Tolerance.
Therefore, do not select other functions except those three.
LAN Advanced Functions 2-15
Hitachi Compute Blade 500 Series LAN Advanced Function Manual (for Intel)