VTAM honors requests for storage dynamically, as permitted by buffer availability. If buffers are not available, VTAM queues the requests until enough storage can be obtained to honor the user request. This situation is triggered when the number of queued requests becomes greater than zero.
If you see this situation occurring over time for a particular pool, then allocate additional base buffers or increase the Expansion Point value. If the situation occurs for an I/O buffer pool, then also consider increasing the Slowpoint value.
This is a warning situation. By default, this situation does not start automatically and should be run as needed, not at startup.