Interface Card Critical Resource Analysis(CRA) Whitepaper for HP-UX 11i v3

Introduction to Critical Resource Analysis
Starting with HP-UX 11i v3, given a set of I/O components, the CRA module performs usage analysis
and reports any potential impacts for specific subsystems, such as Mass Storage, LAN, or Infiniband.
The CRA module returns the highest critical usage reported. The CRA module also collates detailed
analysis logs from all the subsystem CRA modules and returns the combined logs for the user under
the /var/adm directory on the system.
Example:
Consider a CRA framework comprising an infrastructure CRA, a networking subsystem CRA module,
and a mass storage subsystem CRA module. Assume that a 4-port LAN card is being taken offline
(suspended or deleted). The I/O resources to be analyzed for usage are the 4 LAN interface ports on
the card. For CRA purposes, an I/O resource is represented by its hardware path. The infrastructure
CRA module invokes both the networking and mass storage subsystem CRA modules with the
hardware paths for the 4 LAN ports on the IO card. The subsystem CRA modules verify if any LAN
ports are in use within the networking or mass storage subsystems. Each subsystem CRA module
returns its analysis report to the infrastructure CRA module. The infrastructure CRA module then returns
a combined report to its caller.
The CRA is invoked in the following scenarios:
 Card Delete (using
olrad –d)
 Card Suspend (using
olrad –r)
 Card Usage Report (using
olrad –C)
 LAN Card Usage Report (using
nwmgr –cra –c)
 LUN Delete (using
scsimgr command)
 Disable a
lunpath (using scsimgr command)
 Driver unload (using
kcmodule command)
 Removal of legacy device special files (using
rmsf –L command)
 Deletion of VLAN/APA interface (using
nwmgr –delete command)
 Reset of the
lan interface (using nwmgr –reset command )
 Chassis Delete (using
olrad –D –s) during Dynamic nPartition operations
CRA return values
Cumulative CRA is a resource analysis method that checks the overall impact of a destructive
operation on any or all components in the subsystem. The CRA returns the following values at the end
of the analysis:
CRA_SUCCESS - Indicates that no critical usage is detected for the set of components that were
analyzed.
CRA_WARNING – Indicates a warning issued to the user because of a redundant resource being
deleted or taken offline which does not cause any loss of service. A CRA_WARNING could be
returned owing to the potential performance impact of a hardware redundancy that is being removed.
For example, a warning is issued when one of the network links from a networking aggregate is
going down.
CRA_DATA_CRITICAL
- Indicates loss of resources that are classified as not critical to the running
system. However, applications might be affected. If a CRA_DATA_CRITICAL flag is returned, the
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