How do we troubleshoot when discovery fails to discover devices?

There are several aspects needs to be taken care of in the discovery process. Discovery only searches devices connected in the network. So, first of all, please make sure the devices are responsive in the network environment.

Then, discovery sends IPMI/SNMP command packets to the devices based on the protocol. Please check the authentication correctness in the discovery task and the devices do respond normally to the specified protocol.

If the discovery range is really large (ex. over 1000 IP addresses), please make sure the server running QSM meets the recommended hardware specification. Furthermore, if QSM is installed on Linux, the default ARP table size is fixed and needs to be increased.

In Linux, there are a soft and a hard limit for ARP table. The soft limit is better to be the same as the size of discovery range; the hard limit is recommended to be a little larger than it.

* Set Linux soft limit of ARP table:

# sudo sysctl –w net.ipv4.neigh.default.gc_thresh2=<soft limit size>

* Show Linux soft limit of ARP table:

# cat /proc/sys/net/ipv4/neigh/default/gc_thresh2

* Set Linux hard limit of ARP table:

# sudo sysctl –w net.ipv4.ngieh.default.gc_thresh3=<hard limit size>

* Show Linux hard limit of ARP table:

# cat /proc/sys/net/ipv4/neigh/default/gc_thresh3