I'm currently using GPG RSA keys to encrypt binary files. Many people recommend using symmetric keys to encrypt large files, and then encrypt the symmetric key with a public key.
This is known as hybrid cryptosystem and is the way it is usually done, especially when the data sizes get bigger. Symmetric encryption by its very nature is always going to be faster than any asymmetric scheme.
Are there any security concerns with using GPG/RSA on massive files (GB's)? I'm aware that RSA is much slower/larger, I'm just wondering if there were any other issues.
Well, one issue might be the deterministic nature of RSA. If you encrypt the same plaintext using the same key multiple times, you might enable an attacker to perform known-plaintext attacks. You certainly can modify RSA in a non-deterministic way, but why bother and not just use a random symmetric key with each encryption.
Furthermore the hybrid approach makes it possible to send out the ciphertext to more than just one recipient with very little overhead. You only need to encrypt the symmetric key for each recipient, while the bulk of the data can stay the same for all of them.
It's much less hassle to encrypt directly using RSA even if it takes more time, than to generate new symmetrical keys and encrypt via RSA and then store them every time I'm encrypting my files, that's why I'm asking about why I should use it.
This is something that GPG takes care of automatically. How exactly do you invoke GPG? Why would you want to wait longer, if a hybrid approach has no real disadvantages?