Dell PowerVault MD3220 Owner's Manual page 237

Make sure that the network can access the host by using the ping
b
command in the following syntax:
ping <host-name-or-IP-address-of-the-host>.
If the network can access the host, continue to step c. If the network
cannot access the host, skip to step d.
Remove the host with the unresponsive status from the MDSM, and
c
add that host again.
If the host returns to optimal status, you have completed this
procedure.
Make sure that the power to the host is turned on and that the host is
d
operational.
If applicable, make sure that the host bus adapters have been installed
e
in the host.
Examine all external cables and switches or hubs to make sure that
f
you cannot see any damage and that they are tightly connected.
If you have recently replaced or added the controller, restart the host
g
context agent software so that the new controller is found.
If a problem exists, make the appropriate modifications to the host.
4 If you have an out-of-band storage array, use the following procedure. Click
Refresh after each step to make sure of the results:
Make sure that the network can access the controllers by using the
a
ping command. Use the following syntax:
ping <controller-IP-address>.
If the network can access the controllers, continue to step b. If the
network cannot access the controllers, skip to step c.
Remove the storage array with the unresponsive status from MDSM,
b
and add that storage array again.
If the storage array returns to optimal status, you have completed this
procedure.
Troubleshooting: Your Storage Array Software
237