The metric 'swap utilisation (%)' on the node where Grid Control resides, shows permanently a very hig value. Red Hat Linux, 64-bits, 32GB RAM, 4GB swap. Adding 4GB to the swap-file solved the problem.
After installing Oracle Application Server 10.2.0.2, with corresponding OID, Grid Control 10.2.0.5 gave me the obove mentioned error, and the the item OID gave a 'metric collection error'. To fix the metric collection error downloaded and applied Patch 5686191 on top of OID product.This is a sql-script to run against the OID-repository.
Agent (10.2.0.4) crashes – on a site (64-bit) with many databases (10.2.0.3) a lot, intermittently – , too many open files, emagent.trc gives ‘health check’ error Agent gave messages – in the past – like this: Number files opened by Agent is 1140. These files appeared to be the $ORACLE_HOME/dbs/hc<instance>_.dat which is loaded a lot