Expert Advice

N3T_DLC_Accelerated_Bytes  
Situation Description
Suggested Actions
QDIO Accelerator = Yes and IP Address Version = IPv4 and CHANGE (Accelerated Bytes) is less than 1 over three consecutive data sampling intervals

 

The queued direct I/O (QDIO) accelerator function operates at the Data Link Control (DLC) level and positively affects the performance of IP packets routed between QDIO and HiperSockets network interfaces. When the QDIO Accelerator is enabled for an IPv4 address space, the number of transmitted bytes routed outbound using internal queued direct I/O (iQDIO) routing or QDIO Accelerator should increment steadily.

z/OS Communication Server supports not only acceleration of QDIO to HiperSockets (Q to I) and of HiperSockets to QDIO (I to Q), but also acceleration off QDIO to QDIO (Q to Q) and off HiperSockets to HiperSockets (I to I).

If QDIO Accelerator is active, this situation indicates that the QDIO Accelerator routes are not being used. To verify the configuration, see IBM z/OS Communications Server: IP Configuration Reference for details on the QDIOACCELERATOR parameter. It may be the traffic is "bursty" and therefore it is normal to not accelerate in an interval.

This is a warning situation.

 

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