You can use a central data cache to improve the performance of the Alert Monitor when creating the alert monitoring trees. Data for the various nodes is stored on the local application server in this cache, so that expensive RFC calls to the monitored systems are only necessary when the defined life span of the monitoring tree elements in the cache has expired. Depending on the attribute, this is between two minutes (performance attributes) and twenty minutes (text attribute).
In the ideal case, absolutely no RFC calls are required from the central monitoring system, especially if the monitoring data is transferred from remote systems using agents that use push technology as of SAP Web Application Server 6.10. The agents then deliver their values once per minute directly to the central data cache, if they are registered on the server on which the cache is set up.
The basis of the central data cache is the technology of the Internet Server Cache (ISC). This is a cross-process cache in the main memory of an application server.
The central data cache is in the ccmcache subdirectory of the $DIR_DATA subdirectory. You can display the size of the cache and the age of the entries using transaction AL11 (SAP Directories).
Create Logon Group
As the central data cache only exists on one application server, you should ensure that you always call the Alert Monitor on this application server. We recommend that you create a logon group that consists of only one application server:
Activating a Central Data Cache
You activate the central data cache using the profile parameter alert/cache/size_MB. This parameter is not set by default, meaning that the central data cache is deactivated.
We recommend the following values as the size for the central data cache:
|Platform||Recommended Size in MB|
We recommend 4; if you are using a dedicated monitoring system with a small number of users, you can increase the value for the parameter to 10 to 20. Note, however, that the central data cache requires the Extended Global Memory (parameter em/Global_area_MB) when used in the main memory, which can be very scarce on 32 bit platforms due to the restricted address space. In this case, increase the value for the parameter em/Global_area_MB as described in SAP Note 329021.
10% of the parameter em/Global_area_MB, although from experience an increase of alert/cache/size_MB of over 40 does not provide any additional performance benefits. More information: SAP Note 146289.
Registering Agents with this Application Server
Ensure that the NetWeaver management agents are registered with exactly the logon group that you have intended for monitoring using the Alert Monitor. For information about registering the agents, see Registering SAP NetWeaver Components and Hosts in CEN.
You have set up the central data cache on an application server. By setting up a logon group that consists of only this server, you ensure that the central data cache in the Alert Monitor is active if you always logon to this group to use the Alert Monitor.
In your daily work with the Alert Monitor, you are normally only aware of the central data cache due to a better performance and the output Central data cache active at the top of the alert monitoring tree.
If new nodes are not correctly displayed (for example, after a new application server is started), you can delete all entries in the cache at any time. You do this using the Refresh and Invalidate Data Cache pushbutton ( ) (see Actions in the Alert Monitoring Tree ).