vxconfigd consumes a lot of memory when the DMP tunable: dmp_probe_idle_lun is set on.
"pmap" command on vxconfigd process shows continuous growing heap.
This issue is fixed in 5.1SP1RP2P1
As workaround it's possible to change dmp_probe_idle_lun tunable, setting to off with:
# vxdmpadm settune dmp_probe_idle_lun=off
5.1SP1 SFHA on Solaris 10.