User-defined database roles are created by users of a database. If you grant an NT User or Group to a database role, the NT User or Group becomes a user of the database. If you separate the data, indexes, and transaction log to separate disks, it can improve your performance. Unless you limit a file, a file can grow until it uses all the space on a drive. A transaction log backup copies and truncates the database log, removing all transactions before the oldest open transaction.
Transaction log backups support restoration of a database to the point of failure.
A differential backup copies the changes that have been made to a database since its last full backup. Differential backups can be used in place of transaction log backups but doesn't support recovery of a database to the point of failure. A filegroup backup copies groups of files used to make up a database. Backup strategy is based on the length of time you have to perform a backup and how long you want a database recovery to take. The NT Performance Monitor can be used to chart up to the second performance of servers on the network.