What issues may I have by connecting a 10TB hard drive with 7.5 TBs of movies? I read a post that I may have to partition the hard drive into 2TB partitions. Is this correct? Any other issues that I may come across including formatting?
This article may help a little: https://support.roku.com/article/230160368
I haven't seen a definitive answer as to how large a disk is supported. I'd try my 8TB drive to see what happens, but it's formatted as ext4 which isn't supported.
I've heard of 8 TB working OK, but I can't say how the drives were formatted.
More importantly is if your media is acceptable to a Roku player. The container has to be MKV/MP4/MOV/TS/M2TS. No other container is supported. And the codecs within the container must also be supported. For video that means MPEG2/H.262, AVC/H.264, MP4, and if your Roku is 4K capable HEVC/H.265. For audio, you have a few more supported codecs: AC3/DD, DTS (but only to passthrough from an MKV/TS container to a supporting AVR), AAC (2 channel only which is converted to PCM) or LPCM. There's some additional less common audio codecs as well, plus some additional caveats. See this page for more complete support information.
Unless you're completely certain your media is all supported, you might consider instead using a media server on a computer or NAS, and stream the media across the network. Plex and Emby both offer free servers, and have dedicated channels for Roku devices. There's also DLNA servers like Serviio that can be used with Roku Media Player. That's what I use, and I also wrote the profiles that ship with Serviio for Roku devices.
2TB is the limit. You can't use a larger drive partitioned into 2TB partitions.
EDIT
I might be wrong on the drive size. I just happened upon this post where the OP sates he is using a 4TB drive.
Free software Videolan VLC (Windows, Mac, Linux) can be used to transcode other formats into Roku supported formats.
Not the easiest tool to figure out, and the free codecs used don't always code 100% (visible glitches and artefacts).
VLC can also publish a IP video stream but don't think Roku can connect that (more intended for VLC to VLC on separate computers).
VLC is a media player, not a transcoding app. Yes, it can publish a video stream, but not really useful for being able to select and play local media. There is no VLC app/channel for Roku devices, and the developers have stated they will never make one, due to differences in the programming languages used.
For a free transcoding app, Handbrake is one of the best there is. But transcoding a large number of unsupported media could take a very long time to complete. It's far easier to install a media server on a computer and let it do the real time transcoding for any unsupported media. Plex and Emby both offer both a server for the computer and a channel for Roku devices. There are also a number of DLNA servers that work with the Roku Media Player channel. I'm partial to Serviio, and I assisted its author by creating the Roku profiles included with the software.
VLC can absolutely do transcoding, I have used it to do that, taking one file coded with less common codecs and creating another file using more common codecs. It isn't quick or easy, though, but it was the tool I had at the time (locked down work machine where I was allowed VLC, but not other tools).
VLC, might be able to do real time transcode and stream publish on a powerful enough computer, but interface is complex and I don't have a need, so I can't verify that.
Agree there isn't a VLC app for Roku (they do have a cut down Android version), and with demise of non certified apps I can't see any volunteers trying to jump through the many hoops needed.
I have a 8TB hard drive hooked up to my Roku Streambar and it does work. I used AOMI too partition it into NTFS and placed mkv and mp4 files on it and it does play aac 5.1 and ac3 audio tracks. so far i havent had any issues