We are seeing the same error message when attempting to connect with Oncommand (Version 2.0) to a Filer running Ontap 8.02P3:
"The maximum number of Administrative HTTP connections specified by httpd.admin.max_connections has been exceeded"
We increased the httpd.admin.max_connections to 1023 from 512 on advice from Netapp support and we now get an "Uknown" error when connecting from Oncommand.
When running an httpstat -s you can see the open HTTP connections on the Filer increasing over time until they reach < 900 and then the open counter resets and begins to increment again:
TOASTER1> date
Mon Feb 13 08:39:42 GMT 2012
TOASTER1> httpstat -s
Connection
Open Peak Waits
814 1037 0
TOASTER1> date
Mon Feb 13 08:47:21 GMT 2012
TOASTER1> httpstat -s
Connection
Open Peak Waits
928 1037 0
when the Open connections reach the peak and reset we also see an "NFS Down" error in DFM, although NFS is actually running on the Filer.
An "httpstat -a" shows the Errors (44450) and BadRequests (4234) counters incrementing also.
When the Filer is removed from DFM the "httpstat -a" open counter stops incrementing. We have also tried a failover and giveback of the head and the Filer could communicate with Oncommand and DFM for a short time but then the "NFS down errors" re-appeared and the httpstat open connections began incrementing again.
I've sent Netapp some packet captures from the Filer with the issue and a healthy Filer filtered on the DFM IP address as that is what appears to be flooding the Filer with invalid HTTP requests.
Netapp are analysing the packet captures and have open a Bug for this as it only seems to of started since we upgraded to 8.02P3.