You can uncheck the "Enable Agent" checkbox in Agent Schedule data instance.
For that you need to goto the particular Node's Agent Schedule data instance and disable the purge Agent.
Please find the explanation of how these agents work in Multinode Enviornment.
For each Agents rule, the system creates Agent Schedules for each node in a multi-node system. However, for some Legacy-mode agents, contention can occur. As an example, suppose you have a system with four nodes, and an agent has ten tasks that are queued for processing. The agent on Node A picks the first task from the queue, locks the associated work object, and begins processing that task.
The agent on Node B goes to the queue and also picks the first task (which is still there, as it hasn’t been completed). When it tries to get a lock on the work object, it is blocked (since Node A has that lock); the agent on Node B then either goes back to sleep, not having accomplished anything, or chooses the next task in the queue and begins processing that.
Now Node C goes to the queue. It tries the first item, and finds that locked, and then tries the second, and finds that locked. It finally picks up the third item (having wasted system resources trying to process the first two tasks) and processes that. And Node D has to go through the first three tasks before getting to one that isn’t locked.
To prevent this contention, it is recommended that one node be chosen to do the agent processing. The agents on the other nodes should then be disabled, by opening the Agent Schedule form for each node, and unchecking the Enabled box for each agent.
Please let me know on the further concerns , If you have any.
Now I am concerned if the archival process is currently running on our system. As per I know Pega-ImportExport agent is responsible for archive/purge method to run in system,if archive/purge is configured from wizard. To be sure on this, I checked the agent schedule but "Enable agent" checkbox is unchecked in all the nodes for this agent.
Does it mean archival process is not running in system? How to be sure on this?