Regarding CLOB on DB2 z/OS as of January 2019 for both Gen 8.5 and 8.6:
We do not support BLOBs on z/OS, only on distributed.
We do not support CLOBs on either z/OS or distributed.
Also for this case, using 'Windows and Web Clients to CICS/DB2 servers via ECI connection'. Assuming this is Java Web Clients. CLOBs/BLOBs would require ECI V2 (containers for >32k) for Java which, we do not support yet.
January 2019, Gen Management Team responded...
First they noted that they will update the 'Idea' on the communities page to 'Wish-List' the 'Idea', along with adding comments.
They noted: ...We understand the value that CLOB support delivers for our Gen users. The CLOB support on z/OS and distributed requires a larger implementation support, which requires us to perform the analysis of how we can implement this capability in batches. While we focus on the forthcoming Gen 8.6 Complete Release, we would consider doing this analysis in a future release and then weigh this capability along with the other priorities in our product backlog... https://communities.ca.com/ideas/235714879-extend-gen-varchar-fields-to-32k-f49118#comment-233981018