Hello David,
There are many ways to backup a server with a 2 Gb file size limit.
Cold backups can be anthing from copy commands (cp, dd, etc.) to
compress (compress, gzip, etc.). Hot backups can be anything from
informix backup tools (ontape, onbar) to unloads (unload SQL's,
onunload, dbexport).
Good luck!
L.S.