Linux on POWER Odds and Ends: Service Utility Roundup

There are a number of small utilities for Linux on POWER that can come in useful for servicing are configuring your system. Here are a few utilities from the powerpc-utils-papr package that you may find useful.

The set_poweron_time utility can be used to specify a time in the future when the system or partition should be powered on, if it happens to be off at that time. For example, if a partition should be automatically started 12 hours and 10 minutes from now, run the following command: set_poweron_time -d h12m10. If the partition is off when that time expires, it will restart.

The bootlist command is used to modify the order of boot devices from the command line. Boot lists on POWER are stored as Open Firmware device names, but bootlist allows you to specify logical device names (like “sda” or “eth0”) if you choose; the ofpathname utility is used by bootlist to convert between OF device names and logical device names (between “/vdevice/v-scsi@30000002/disk@8100000000000000” and “sda”, for example).

usysident is a tool for manipulating identification LEDs. These LEDs are used to help locate FRUs (field replaceable units), to ensure that the correct part is being replaced. LEDs are specified by their location code or logical device name, and can be in one of two states: either “normal” (off) or “identify” (blinking amber LED). Run usysident without any parameters to view the available LEDs; to flash the LED on eth0: usysident -d eth0 -s identify.

A related utility is usysattn; it’s used to turn off the system attention indicator, or to view the current state of that LED. The LED usually looks like an amber exclamation point located on the operator’s panel, as in the image below from a p520.

POWER5 op panelOn a partitioned system, though, the system attention indicator will be illuminated if any of the partitions have activated it. This is because the system attention indicator determines whether any of the partitions require attention. Refer to the Service Focal Point on the HMC or IVM to determine who is asking for attention.

serv_config is a very useful utility for modifying serviceability parameters. I talked a little about it in an earlier post, so refer to that entry for more details.

The uesensor command can be used to view the values of various thermal, voltage, and fan speed sensors on the system. Unfortunately, these sensors are only exposed on POWER4 systems and some blades; more recent systems will instead send an EPOW (environmental or power warning) event if any of the sensors are in danger of shifting out of the normal operating range. EPOW events are exposed in servicelog.

All of these commands have man pages; take a look there if you need more details.


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