What is the cavader agreement file - agreement.cdv?
In the go source I can see that there is an option to disable it. Can I safely do so in an archival node if I want an indexer to be able to run of it?
What is the cadaver agreement file?
Yes, it wouldnt be a bad thing to disable it. It used for debugging the agreement protocol, which I don’t believe you’re working on. 
Nice one, thank you. I disabled it and it seems to have freed up some disk I/O resulting in somewhat increased blocks synced per minute