RockSolid uses several methods of monitoring to collect data from monitoring instances. This includes TSQL, powershell, perfmon and WMI counters. When monitoring SQL Server instances, the bulk of monitoring data comes from TSQL based feeds however certain data relating to the OSE environment comes from WMI.
If some cases it is possible to have appropriate permissions granted so that RockSolid can monitor the TSQL feeds, but insufficient rights for RockSolid to monitor the WMI feeds. In this case RockSolid will not raise a "Server Down" alert, but will instead raise a warning that key WMI information such as Disk Space information is not available.
To resolve the lack of disk information being captured, the focus needs to be on the RockSolid Agent services accounts permissions to capture WMI information. Typically sites will add this service account to the the local administrators group on the target host, however if this is not desired appropriate permissions can be granted to the various monitoring points without granting admin access (see the RockSolid security whitepaper).
In addition to access permissions, firewalling between the RockSolidAgent and the target host needs to be considered. The TSQL feeds will take place over the allocated TDS port for SQL Server whereas WMI monitoring requires access to the windows RPC port range. In some cases network admins will grant access to the TDS port but will block windows RPC ports, in these cases RockSolid will not be able to gather any WMI based counters.
The RockSolid Connection Tester tool can be useful for resolving such issues.