Scott Davenport @ Sun: (Mainly) Fault Management

Earlier this week, an account architect for a large European bank asked me about the SNMP traps that are generated on the SPARC CMT systems, specifically the T5220 and T5240 systems. On these systems, both the ILOM stack on the SP and the Solaris FMA stack on the host hardware are capable of generating SNMP traps for fault conditions. Our customer wanted to know if it was sufficient to monitor the traps from solely Solaris FMA. The short answer is both Solaris FMA and ILOM traps must be monitored to ensure full coverage. The rest of this entry is to detail the reasons why.

For the purposes of this discussion, I'll refer to an SNMP trap from Solaris FMA as an "FMA SNMP trap" and one from ILOM as an "ILOM SNMP trap".

The key to understanding why both ILOM and Solaris must be monitored is the flow of fault information in the system. This picture (admittedly simplified) should help:

For faults generated in their respective precinct, ILOM diagnosed faults will produce an ILOM SNMP trap. And Solaris FMA faults will produce an FMA SNMP trap (via the snmp-trapgen plugin). And there's a level of fault sharing between ILOM and Solaris - but notice the flow of fault information is from Solaris to ILOM.

In Solaris, an FMD plugin called the Event Transport Module (ETM) subscribes to selected fault events and (you guessed it) transports them to ILOM. ILOM then updates its state and view of the components in the system. And for faults received from Solaris, ILOM will also generate an SNMP trap. However, ETM does not transport all fault events. Some fault events are not meaningful to ILOM as they represent components beyond ILOM's visibility. Precisely which faults are forwarded by ETM is driven by a configuration file, etm.conf, tailored for each platform or platform family.

This gives us a few flows for SNMP trap generation.

• FMA diagnosed fault that is transported to ILOM: snmp-trapgen in Solaris generates an FMA SNMP trap. And ILOM generates an ILOM SNMP trap when the fault is received in the service processor.
• FMA diagnosed fault that is not transported to ILOM: snmp-trapgen in Solaris generates an FMA SNMP trap.
• ILOM diagnosed fault: ILOM generates an ILOM SNMP trap
• ILOM chassis event: ILOM generates an ILOM SNMP trap

Summing this up, taking into account the faults that ETM will forward to ILOM, we can expect the following SNMP trap generation for the various subsystems:

Subsystem	FMA SNMP Trap	ILOM SNMP Trap
Processor/Cache	yes	yes
Memory	yes	yes
PCI/PCIE	yes	yes
Coherency Links1	yes	yes
ZFS	yes	no
Disks	yes	no
SCSI	yes	no
Power/Cooling	no	yes
Environmental/Sensors	no	yes
ASR Disables	no	yes
Component Insertion/Removal	no	yes
1 T5440 and derivatives only

As I'm not an expert on ILOM, the table above may not be an exhaustive list of all of the ILOM events that can trigger an ILOM SNMP trap. But I believe it's sufficient to illustrate the point that if you're monitoring your SPARC CMT systems via SNMP, you must monitor both ILOM SNMP and FMA SNMP traps.

:wq