I cannot find a version of Splunk for zLinux e390/s390x (IBM Z-series) on www.splunk.com. Where can I find that? Would also be interesting to hear if anyone has any experiences running Splunk on IBM Z-series.
Splunk has not released such a version and does not support running it on this platform.
There is a fully supported s390x Universal Forwarder on the Splunk forwarder download page under Linux in tgz and rpm format:
http://www.splunk.com/en_us/download/universal-forwarder.html
The closest I've come is to export CA-TSS/LDS journal files via FTP and index them on another host.
Splunk has not released such a version and does not support running it on this platform.