Sometimes, a host (LPAR) will stop sending its performance data to the xmtopas and xmtopasagg processes on the collecting LPAR (the one running /usr/bin/topasrec -C).
To fix this, login to the LPAR in question and do the following:
# ps -fe | grep topas
root 278702 168026 0 Apr 10 - 1:17 xmtopas -p3
You are looking for the 'xmtopas -p3' process.
# kill {PID}
This should respawn itself within a minute when the xmtopas collecting LPAR next polls.
# ps -fe | grep topas
root 1503396 168026 0 09:24:32 - 0:00 xmtopas -p3
Regards, Steve.