In an HACWS configuration the tty assignments for each frame must be identical on both the primary and backup control workstations. The new frame supervisor cards (Type 22 and 20) used for HACWS configurations have flash memory on the cards. This flash memory is used to write a unique ID so the frame can be identified. With previous cards the order in which the frames were cabled determined the frame numbers in the configuration. There was no method to check that the frame was actually still the same frame number.
If a frame number on the card does not match the frame number in the SDR, the hardware monitor will not bring the frame online. An error log entry is written to the AIX error log and BSD syslog indicating this. Note that in most cases of incorrect cabling, two frames will not be brought online. An error log entry will be written for each frame. You have to correct the cabling to repair the situation.
When the hardmon daemon initializes it verifies that the frame supervisor cables match the information in the SDR. To check that the cables are correct from an inactive control workstation (there must be an active control workstation in order to compare the SDR information):
Any cable problems will be written to the AIX error log.
When an SP system is reconfigured and frames are moved around and reassigned, new frame IDs need to be written to existing frames. Note that the system must be completely reinstalled so node numbers and system images are correct. This action should rarely, if ever, be taken.
The following example lists the steps to change the frame numbers in the flash memory of the card. In this example frame number 4 is now frame number 6 and frame number 6 is now frame number 4. A complete reinstall of the SP system is also being done. Note that it would be far easier to make the cables match and not swap frames around. Swapping frames should be done only in extreme cases.
Ensure that the SDR information about the frame and tty number match how the frame is cabled. Use the SDRGetObjects Frame command to see which frame number matches with which tty number. Assuming that the SDR information is correct, proceed to the next step.
If the tty number in the SDR is incorrect, use the spframe command to make frame number 6 use the correct tty special device name. For example, if you want to make frame 6 use /dev/tty6 (assuming no other frame is using /dev/tty6), enter spframe 6 1 /dev/tty6.
Enter hcmds -G setid 4,6:0 to set the frame ID to the values in the SDR frame class for frames 4 and 6.