Remote Network Agent is shown as active and connected, yet it fails to update its monitors’ state – how to solve that?
Q: I noticed that several remote network agents I use write to their log files messages about not enough TCP connections and/or threads. How to handle this?
A: Remote Network Agents can remove extra load off your main installation, if you plan to monitor several thousand devices. Main installation uses less resources itself, part of resources required are provided by agents (usually run on multiple different computers).
However, if there are too many monitors to be served by single agent, its resources (such as number of TCP connections it can open simultaneously; number of execution threads etc) can also be exhausted. To prevent that, try distributing load across several agents. There’s no strict bound above which agent should serve more monitors, but the rule of thumb is: try to distribute all types of monitors evenly across several agents, wherever possible.
If you create similar monitors sets for a number of devices (i.e., the same monitor types for multiple devices). try assigning hosts running those monitors sets on separate agents evenly.
Note also: different monitor types create different amount of load (take different amount of resources – CPU time, memory etc). The table below gives approximate estimation of how much resources can consume various monitor types.
|<— Less resources More resources —>|
(PING, TCP, UDP)
(IMAP, POP3, SMTP; HTTP(S), FTP, DNS; running program over SSH)
|Network, Resources, Database, Traffic
(SNMP – Generic Monitors and Traps; WMI queries; MySQL, MSSQL, Oracle, ODBC)
|Web Transaction Monitor|
Generic monitor “Run Program or Script” can take any amount of resources, all depends on what exactly it runs – that is, its impact can only be tested experimentally. Also, WMI and SNMP queries can take very different amount of resources as well, all depends on actual monitor parameters.
If you distribute load across agents evenly enough, with the above estimated monitors “weight” in mind, you could avoid situation when agent runs out of resources.
Note that you can also create monitors on different agents to check agent logs of one another, for records indicating resources depletion – thus informing main installation that agents are overloaded.
However, if you use 4.0.10090 or newer release of IPHost Network Monitor, you can configure a remote network agent system limits. Open Settings -> Remote Agents page, select an agent and click Settings button on the right. You can set the system limits for the agent on the Agent Settings dialogue page: