Potential exposure for undetected loss of data for z/OS users writing data to zEDC compressed data sets using QSAM

Here's a new Red Alert. I'm taking over the content.

Abstract:

Potential exposure for undetected loss of data for z/OS users writing data to zEDC compressed data sets using QSAM on releases z/OS 1.13, 2.1 & 2.2.

Description

Data loss may occur when writing to a zEDC compressed data set using QSAM when CLOSE is issued and there exists a partial QSAM buffer that has not yet been written, and all allocated space in the data set is filled. In this case, the unwritten partial buffer may not be written after CLOSE processing obtains the new extent for the data set.

The problem does not apply to BSAM or other access methods.

Please see APAR OA50061 for additional information.

Recommended Actions 
++APAR for OA50061 should be applied for all environments with zEDC compressed data sets. This requires an IPL to activate.

You can find the APAR information over here where you can find some more info :

"During creation of a new extent during CLOSE processing, any
user blocks that have not been compressed and written out to the
zedc compressed dataset yet will not be written out.

This does not apply to BSAM processing since all outstanding
WRITE requests must be CHECK'd for completion before CLOSE is
issued."

For the moment it also says : "++APAR will be available soon".

If you haven't signed up to the Red Alerts by now, you really should do it. Just go over here.