Question & Answer
Question
Is there any documentation about the meaning of the additional status flags found in the compression information message?
Cause
Connect:Direct for z/OS 5.2 PTF UI44765 introduced additional status flags to assist in analysis of the use of ZEDC verses ZIIP. Connect:Direct 6.0 introduced a new status flag.
Answer
Connect:Direct z/OS 6.0 introduced enhanced zLIB compression support to allow for better buffering of data prior to compression to ensure more data is eligible for compression and eligible for zEDC compression. As a result, a new status flag, ZLIB-Buffering, was introduced to those already made available in Connect:Direct z/OS 5.2.
The CDz 5.2 PTF UI44765 (APAR PI74504) was a Small Programming Enhancement (SPE) that allowed the user to define a precedence for zEDC over zIIP. The HOLDDATA for this PTF gives an explanation of the new status flags found in the statistical data. This applies to releases 5.2 and later.
| Status Flag | Explanation |
| ZEDC | The zEDC feature was requested and used. |
| ZEDC-OFF-WIN | The ZEDC feature was requested but turned off because there was no way to force the receiving node to use the required WIN=15. The ZEDC feature requires WIN as 15 and if was not possible to force WIN to 15. |
| ZEDC-HW-SEND | The ZEDC feature was requested but turned off |
| ZEDC-HW-RECV | because the zEDC accelerator card rejected the first data block via the DEFMINREQSIZE or INFMINREQSIZE in the QPPRMxx parmlib member. |
| ZEDC-HW-RACF | The ZEDC feature was requested but turned off because ZLIB initialization hwCHECK RC=2, usually because access was denied by the security package (RACF). |
| ZEDC-Offline | The ZEDC feature was requested but turned off because no zEDC accelerator card was online when the COPY started and fallback to ZIIP was not possible. |
| ZIIP-Project | The INITPARM ZIIP=PROJECT was specified. This takes precedence over ZEDC. |
| ZIIP-Fallback | The ZEDC feature was requested but it could not be used for one of the above reasons. The ZIIP feature was also enabled and was used as the preferred method. |
| ZIIP | The ZIIP feature was requested and used. |
| WIN15 | The ZLIB WINDOWSIZE=15 parameter was forced. |
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Document Information
Modified date:
22 April 2024
UID
swg22007439