You are the systems administrator for your company. You install Windows Essential Business Server 2008 Premium Edition on the network. A server named EBS-SQL4 is configured as the SQL Server database server. EBS-SQL4 contains two hard disks named DataDisk and Log Disk. A database named Userdb is stored on DataDisk. The transaction log for the Userdb database is stored on Log Disk.

Your company’s IT policy states that any data loss must not exceed one hour’s worth of data. You configure backups on EBS-SQL4 to run as follows:

* Full backup – every Sunday at 1:00 A.M.
* Differential backup – daily at 4:00 A.M.
* Transaction log backup – every hour

The Userdb database on EBS-SQL4 becomes corrupt on Wednesday at 3:20 P.M. You want to restore the database to the point of failure.

Which step should you perform first?

A.
Perform a tail-log backup.

B.
Apply the tail-log backup.

C.
Apply all transaction log backups in the order they were created after the differential backup that was created on Wednesday at 4:00 A.M.

D.
Restore the differential backup that was created on Wednesday at 4:00 A.M.

E.
Restore the full backup that was created on Sunday.

Explanation:
To restore a database to the point of failure, you should perform a backup of the tail-log before restoring the most recent full and differential database backups. The tail-log backup is a backup of the active transaction log that was not included in the most recent transaction log backup. After creating the tail-log backup, you should restore the most recent backup of the full database. After that step, you should restore the most recent backup of the differential database that was created after the backup of the full database that you have restored. Then you should apply all backups, in sequential order, of the transaction logs that were created after the last differential backup. Finally, you should apply the tail-log backup that you created at the beginning of the restoration process.

If the transaction log is also corrupted, you will not be able to perform the tail-log backup. In that case, you will not be able to restore data that was generated after the last transaction log was backed up.

You should not begin by restoring the tail-log backup. You must first perform a backup of the tail-log to be able to restore it.

You should not begin by applying all transaction log backups in the order they were created after the differential backup created on Wednesday at 4:00 A.M. To restore a database to the point of failure, you should first perform a backup of the tail-log, then restore the most recent full and differential database backups, and finally apply all transaction log backups.

You should not begin by restoring the differential backup that was created on Wednesday at 4:00 A.M. Before restoring the differential backup, you must restore the differential base, which is the full backup that was created before the differential backup.

You should not begin by restoring the full backup that was created on Sunday. To restore a database to the point of failure, you should first perform a backup of the tail-log before restoring the most recent full and differential database backups.