EC2 instance with 80TB storage

One thing to take a look at would be Amazon FSx for Windows File Server. It can handle up to 64TiB per storage system (and you can run multiple). This might do the trick to get you over the line.

A Volume Gateway running Cached Mode will give you up to 32TiB, and the caching might resolve some of your I/O issues. Again, you can run multiple volumes per gateway.

The other things you could include using Ephemeral Storage. For high I/O, I'm thinking m5d instances, unless you need really high I/O with an i3 instance. You'd just have to be thinking about backup and recovery processes, which could be pretty nightmarish.

References:
https://aws.amazon.com/fsx/windows/
https://docs.aws.amazon.com/fsx/latest/WindowsGuide/limits.html
https://docs.aws.amazon.com/storagegateway/latest/userguide/resource-gateway-limits.html

Thanks Stephen. I agree with you and will take a look at these. I actually need this server for our Veeam Backup & Replication Solution - Backup Repository server - so it is little tricky here.
Do you have any specific recommendations around using it for repository server?

Thanks!

I can probably attach multiple ebs volumes to my ec2 instance to make it 80TB?

Attach multiple 16 TB EBS volumes