In /var/log/messages from the server where varzfetcher is running, you may have the following messages or something similar:

Jul 21 11:55:14 machine-name rrdcached[6320]: queue_thread_main: rrd_update_r (/var/opt/silvertail/rrd/SilverSurfer/0/--some-name--.rrd) failed with status -1. (mmaping file '/var/opt/silvertail/rrd/SilverSurfer/0/--some-name--.rrd': Invalid argument)

Varz Fetcher doesn?t use the admin user/password, it uses a different account/password that is only synced to all of the nodes when you change the admin password in SilverCat.

If you?re not seeing data in Varz, then the best first option is always to go and change the admin password in SilverCat. 

You can ?change? it to the same thing it?s currently set to ? it?s just the act of changing it that causes it to generate a new random password for the account it uses and re-sync it across all nodes.

NOTE: To confirm RSA Silvercat password sync is the problem, the VARZ should actually be running and created and you should be able to fetch them manually.

                Try retrieving the varz via a browser to:   https://tap-machine-name:4448/srv/sysstats/tap-machine-name/varz  as well as via curl from the command line server where varzfetcher  is running and they both should work fine and thus retrieve varz.

 If the varz are being generated on the tap servers, but not loading in the main server varzgrapher page, this should be the fix...sync the passwords via RSA Silvercat password change/update.