I am attempting to upload a few add-ons manually as .jar or .obr files. I do not have the ability to automatically upgrade the add-ons as we do not have access to the connect to the marketplace from the server.
We are running Jira 7.12.2 Windows Server 2012 R2 and IIS 8.5.
The page itself continues to try installing forever and never logs anything in the Jira logs. I was able to get the 413 Request Entity Too Large error when looking at the console in Chrome. It does the same thing in IE or Firefox.
All I could find in Jira support pages talks about changing the client_max_body_size which I found to be a Nginx command.
https://confluence.atlassian.com/stashkb/updating-add-ons-by-file-upload-hangs-using-upm-660735049.html
I did find a page that says to change the uploadreadaheadsize in IIS. I changed that to 100MB and restarted the IIS site and eventually the entire server. It was at the default setting of 49K.
https://craftcms.stackexchange.com/questions/2328/413-request-entity-too-large-error-with-uploading-a-file
I have run into the issue with the BigPicture and ProForma add-ons which are both in the 40-50MB range.