How is information stored on the SEP server, and what security is provided?
The SEP Server uses common SQL procedures, tables and data blobs and will therefore not interfere with security measurements in place. SEP will authenticate against the SQL server and statically encrypt shared secrets and passwords. The encryption is AES 128 BIT, using .net security classes. Logs are compressed for storage reasons, and as such not directly readable.
Outside of that it is the DB Administrators' responsibility to provide on-site security and redundancy. This can be full disk encryption, clustering or any of the common SQL backup procedures.