Networker 8.2.3.8, on Windows 2012r2

Hi all.

I find surprisingly little information online about this, given how large indexes can grow. I have one particular client index that is 505gb alone.  Im trying to test a different client, while pointing its index path to a folder I have created on an Isilon cif share. i have added the share as a mapped drive on my Networker server (I: drive), and can access anything in the share, as expected. But, when I place that drive letter in the index path, it errors with "failed to create index directory I:\ : No such file or directory." 

So, i thought it may not like translating that drive letter, so I entered the full path. When i do that, I get "access denied." Thats more promising, but the credentials should already be in place.

I would be surprised if there is no way to do this. Anyone successfully been able to pull this off? And if so, are there any downsides to doing that, like maybe a performance hit, because the index repository would be somewhere else?

Thanks!

Todd