I can check that 80% of my disk is used in my Search Head. How to decrease it and what exactly is taking up space? This SH is not the INDEXER, therefore it does not store incoming data.
Search heads need space too, for things like search artifacts:
You should check to see where the disk space is being used, and to make sure that your search head is in fact forwarding events to the index tier.
I would check the DMC first to check if the SH if not listed as a IDX
and also review the indexer instance
There could be internal logs that could consume the disk space, so check that you're forwarding those to the IDX's.