Expert Advice

N3V_BuffPool_Buf_Expan_Lim_Pct  
Situation Description
Suggested Actions
Situation Description

Percentage of total number of I/O buffers compared to expansion limit (IO buffer pool only)

 

Suggested Actions

The I/O buffer pool manages the storage of all network input/output messages sent from application programs and across channel connections. All network traffic passes through this pool, regardless of its destination. This buffer pool also contains channel programs used to service locally attached devices.

The maximum number of I/O buffers allowed is calculated by VTAM from the Expansion Limit value specified in IOBUF statement in the VTAM start options (for example, SYS1.VTAMLST(ATCSTRxx)).

When calculating this limit, VTAM takes into account how many buffers fit on a page. If XPANLIM is not specified in buffer definition or is coded 0, buffer expansion is not limited and a value of 2,147,483,647 is displayed in the field.

This situation is triggered when Expansion Limit is greater than 90% of its capacity. To address this situation, increase the Expansion Limit value.

This is a critical situation. By default, this situation starts automatically. It should be run at startup.

Note: Applies to the I/O buffer pool only.

 

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