AP7921 shutdown & throwing errors.

[quincy.hartgers_apc]

Dear reader,

Our APC is throwing the following errors:

11/30/2011	11:10:00	Switched Rack PDU: Communications lost.
11/30/2011	11:09:58	Switched Rack PDU: Communications established.
11/30/2011	11:09:58	Switched Rack PDU: Communications lost.
11/30/2011	11:09:56	Switched Rack PDU: Communications established.
11/30/2011	11:09:46	System: Network service started. System IP is xxx.xxx.xxx.24 from manually configured settings.
11/30/2011	11:09:46	System: Warmstart.
11/30/2011	11:09:30	System: Restarting. Stack overrun - Task 10.Stack overrun.
11/30/2011	10:40:32	Switched Rack PDU: Communications established.
11/30/2011	10:40:32	Switched Rack PDU: Communications lost.

Please ignore the datetimestamps; these are incorrect. Seems this either was reset or never set at all by my predecessor. Anyway; the PDU suddenly stopped functioning a couple of days ago causing all outlets to die (and subsequently, the attached servers). So I went searching in the event log of the PDU and, apart from the above, found nothing to go on. All I could find was this (seemingly unrelated to events):

11/30/2011      17:21:26      2.0      2.4      2.0
11/30/2011      17:11:26      2.1      3.0      0.0
11/30/2011      16:59:33                      
11/30/2011      16:49:33      0.0      0.0      0.0
11/30/2011      16:39:33      0.0      0.0      0.0
...
11/30/2011      11:49:33      0.0      0.0      0.0
11/30/2011      11:39:33      0.0      0.0      0.0
11/30/2011      11:29:33      0.0      0.0      0.0
11/30/2011      11:19:33      0.0      2.1      0.0
11/30/2011      11:05:05      2.0      2.2      2.0
11/30/2011      10:55:05      2.1      2.2      2.0
11/30/2011      10:45:05      2.1      2.1      0.0
11/30/2011      10:35:05      2.0      2.2      2.0 

Regardless, I did a bit of searching and concluded that there's three ways to go for me:

1) 30-second power cycle on the PDU;

2) Try to update the firmware;

3) Replace the PDUs (obsolete model).

Is this correct? Am I overlooking anything?

In regards to option (2); where can I grab the most recent firmware for this specific model?

Thanks a lot --

Model Number:     AP7921
Serial Number:     ZA0716000626
Hardware Revision:     B2
Manufacture Date:     04/21/2007
MAC Address:     00 C0 B7 30 17 AF
Management Uptime:     0 Days 0 Hours 7 Minutes

# APC Module
Name:     rpdu
Version:     v3.3.3
Date:     01/05/2007
Time:     14:56:33

# APC OS
Name:     aos
Version:     v3.3.4
Date:     01/05/2007
Time:     14:23:44

[B-DoubleE_apc · Accepted solution]

Hi Quincy,

The symptoms described sound like the starting of a failure of one or both of the internal power supplies. A switched PDU has multiple internal power supplies so if the network card reboots (as evident by the warmstart in the event log) the outlets will remain on. If there is an issue with the power supplies that can lead to issues like the one you explained. 

This PDU is over 12 years old (and the expected life of a PDU is 8-10 years), so while trying to upgrade firmware and powercycle the unit are valid steps, I think a replacement is going to be your best option.