Hitachi CB 520H A1 User Manual page 78

2 HBA-core dedicated mode can be enabled, but only one LPAR can be used for one
.
port.
Setting procedure
You can use HvmSh to set HBA-core dedicated mode to FC ports that are
configured as Shared FC.
Notes
Even if HBA-core dedicated mode is enabled, because it is inevitable that
resources shared by other LPARs (for example, FC ports) exist in the system,
the other LPARs might interfere with performance. To reduce the system's
vulnerability to this interference, take the following points into account when
you build the system:
• Make sure that the RAID group of the LU being used is not shared by
other LPARs or systems.
• Set the maximum bandwidth for the FC port. As a result, LPARs that
share the FC ports become less likely to be affected by the concentration
of communication.
• For a system running in LPARs that share the same FC port, it is
recommended that the system requests less large-volumed I/O
processing and more small-volumed I/O processing for the storage.
Restrictions
The following shows major restrictions that are placed if HBA-core dedicated
mode is enabled:
• Setting the HBA-core dedicated mode
You must deactivate the LPARs to which an FC port is assigned in advance
when you change HBA-core dedicated mode to the FC port from a value
of "enabled" to that of "disabled", and vice versa.
• Maximum number of FCs that can be shared
The maximum value of the vfcID that can be assigned is limited to the
number of HBA cores in the FC adapter. Although a vfcID greater than the
number of HBA cores can be assigned to the LPAR, activation of the LPAR
is suppressed.
• Maximum performance
An LPAR cannot use HBA cores that are not allocated to the LPAR (even
when they are idle). Therefore, the maximum IOPS that can be obtained
with one core determines the overall maximum IOPS.
For example, if HBA-core dedicated mode is enabled for an FC adapter
that has 2 cores per port, the maximum IOPS is half the maximum IOPS
obtained when HBA-core dedicated mode is disabled.
• Core assignment
1-64
Hitachi Compute Blade 500 Series Logical partitioning manager User's Guide
Item Number of coresport
LPAR manager Functions
1
Assignable vfcID