Hitachi Compute Blade 2000 User Manual page 1354

(3) Notes
Virtual NIC function Network Performance

The Virtual NIC function is actually implemented as a NIC emulated by LPAR
manager. The network performance is lower than physical NICs, and may vary
depending on conditions such as processor activity. When communicating with
external networks, as the number of virtual NICs sharing a physical NIC
increases, the virtual NIC network performance falls, and the overhead and its
variation from the physical NIC become larger.
Therefore, it is recommended that you use virtual NICs and physical NICs
properly according to the environment in which virtual NICs are used or the
requirements such as the bandwidth.
With many physical LAN controllers or high-speed 10 Gb LAN controller
installed, their bandwidth may not be fully used.
Addition and Deletion of Shared NICs/VF NICs to/from the activated LPAR

It is not possible to add or delete a shared NIC or VF NIC to/from the activated
LPAR. To change the configuration, all the LPARs have to deactivate once.
Configuration takes a few minutes.
Therefore, it is recommended that you set the configuration before you activate
LPARs.
NIC Communication during Physical NIC Failure

If a failure occurs in a physical NIC, the NICs sharing the failed physical LAN
controller may become unable to communicate with the external servers and
other LPARs.
If an automatically recoverable hardware failure occurs, communication may
be temporarily disabled for recovery. In such a case, communication is
disabled for approximately 60 seconds, which may cause some applications to
detect a communication error and terminate abnormally.
It is recommended to set the communication failure recovery wait time to a
sufficiently large value or make the system redundant.
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