Backup and Recovery in SQL Server

High Level View

PlanningNeeds assessmentManagement expectationsNetwork architecturePersonnel

ImplementationTrainingWhos involved in the process?TestingFailsafe your processRemember what the purpose of backups are!

The Role of Back-upsData RecoveryData Migration

Backing up your data

Backup Basics Data Files .MDF .LDFBackup Devices Create Delete

Recovery ModelsSimple Most restrictive model. Cant complete transaction log backups. Good if you only want to recover to your last full backup.Bulked Log Ability to recover to the end of a full backup or the end of a transaction log. Lose the ability to restore to a specific point in time.FullAllows full, differential, transaction log and filegroup recoveries. Provides the highest level of data protection.Point in time restores.

Types of BackupsFull DatabaseDifferential DatabaseTransaction LogFilegroup

FullCompletes a full backup up the database right up to the point where the database finishes.Backs up all tables, indexes, system tables and the database object in those tablesStriping example

The Backup Database StatementBACKUP DATABASE { database_name | @database_name_var } TO < backup_device > [ ,...n ] [ WITH [ BLOCKSIZE = { blocksize | @blocksize_variable } ] [ [ , ] DESCRIPTION = { 'text' | @text_variable } ] [ [ , ] DIFFERENTIAL ] [ [ , ] EXPIREDATE = { date | @date_var } | RETAINDAYS = { days | @days_var } ] [ [ , ] PASSWORD = { password | @password_variable } ] [ [ , ] FORMAT | NOFORMAT ] [ [ , ] { INIT | NOINIT } ] [ [ , ] MEDIADESCRIPTION = { 'text' | @text_variable } ] [ [ , ] MEDIANAME = { media_name | @media_name_variable } ] [ [ , ] MEDIAPASSWORD = { mediapassword | @mediapassword_variable } ] [ [ , ] NAME = { backup_set_name | @backup_set_name_var } ] [ [ , ] { NOSKIP | SKIP } ] [ [ , ] { NOREWIND | REWIND } ] [ [ , ] { NOUNLOAD | UNLOAD } ] [ [ , ] RESTART ] [ [ , ] STATS [ = percentage ] ]

Differential BackupCreates a backup of the changes made to the database since the last full backupDoes not keep track of individual transactions so it does not provide the ability to restore to a point in time

The Transaction LogThe transaction log keeps a log of each transaction giving a DBA the ability roll forward or roll back to a specific point.When the transaction log is backed up the log is truncated.Transaction log backups are scheduled in intervals typically 5 to 30 minutes.Backs up the transactions since the last Full Backup, Differential Backup or Transaction Log Backup.

Backup Log StatementBACKUP LOG { database_name | @database_name_var } { TO < backup_device > [ ,...n ] [ WITH [ BLOCKSIZE = { blocksize | @blocksize_variable } ] [ [ , ] DESCRIPTION = { 'text' | @text_variable } ] [ [ ,] EXPIREDATE = { date | @date_var } | RETAINDAYS = { days | @days_var } ] [ [ , ] PASSWORD = { password | @password_variable } ] [ [ , ] FORMAT | NOFORMAT ] [ [ , ] { INIT | NOINIT } ] [ [ , ] MEDIADESCRIPTION = { 'text' | @text_variable } ] [ [ , ] MEDIANAME = { media_name | @media_name_variable } ] [ [ , ] MEDIAPASSWORD = { mediapassword | @mediapassword_variable } ] [ [ , ] NAME = { backup_set_name | @backup_set_name_var } ] [ [ , ] NO_TRUNCATE ] [ [ , ] { NORECOVERY | STANDBY = undo_file_name } ] [ [ , ] { NOREWIND | REWIND } ][ [ , ] { NOSKIP | SKIP } ] [ [ , ] { NOUNLOAD | UNLOAD } ] [ [ , ] RESTART ] [ [ , ] STATS [ = percentage ] ] ]

FilegroupsAllow a user to place tables, indexes and other database objects into specific database files.Can be backed up and restored individually or in groups.Useful when time restraints prevent full backups.

Backup Filegroup StatementBACKUP DATABASE { database_name | @database_name_var } < file_or_filegroup > [ ,...n ] TO < backup_device > [ ,...n ] [ WITH[ BLOCKSIZE = { blocksize | @blocksize_variable } ] [ [ , ] DESCRIPTION = { 'text' | @text_variable } ] [ [ , ] DIFFERENTIAL ] [ [ , ] EXPIREDATE = { date | @date_var } | RETAINDAYS = { days | @days_var } ] [ [ , ] PASSWORD = { password | @password_variable } ] [ [ , ] FORMAT | NOFORMAT ] [ [ , ] { INIT | NOINIT } ] [ [ , ] MEDIADESCRIPTION = { 'text' | @text_variable } ] [ [ , ] MEDIANAME = { media_name | @media_name_variable } ] [ [ , ] MEDIAPASSWORD = { mediapassword | @mediapassword_variable } ] [ [ , ] NAME = { backup_set_name | @backup_set_name_var } ] [ [ , ] { NOSKIP | SKIP } ] [ [ , ] { NOREWIND | REWIND } ][ [ , ] { NOUNLOAD | UNLOAD } ] [ [ , ] RESTART ] [ [ , ] STATS [ = percentage ] ] ]

Verifying the BackupDoes not check the consistency of the database (i.e. DBCC CHECKDATABASE).Verifies the integrity of the database backup and checks for corruption.Makes sure all the data in the backup set is readable.

Restore Verify OnlyRESTORE VERIFYONLY FROM < backup_device > [ ,...n ] [ WITH [ FILE = file_number ] [ [ , ] { NOUNLOAD | UNLOAD } ] [ [ , ] LOADHISTORY ] [ [ , ] PASSWORD = { password | @password_variable } ] [ [ , ] MEDIAPASSWORD = { mediapassword | @mediapassword_variable } ] [ [ , ] { NOREWIND | REWIND } ]

Job SchedulingThe most widely used way complete day to day and week to week scheduled backup operations.Creation of jobs though Enterprise Manager.SQL Server Agent must be started.

Database Maintenance PlansExpanded job scheduling abilities.Creates jobs managed by the SQL Server Agent.Can schedule integrity checks, reorganize indexes and delete unwanted database backups.

StorageUsing a consistent method of keeping track of your backups.Using the system backup tables in the msdb database.Archiving backups to tape and different considerations for different industries

Intermission

Recovering your data

Restore scenarios Data MigrationDevelopmentTestingDisaster RecoveryRecovering BackupsStandby Servers

Restore BasicsMake sure you are using the correct backup set.RESTORE LABELONLY: summarizes information about the backup set.RESTORE HEADERONLY: returns information about each item in the backup set including the order in which the backups were made.RESTORE FILELISTONLY: returns the associated data files in relation to a specific backup device.

MSDB TablesBackupfileBackupMediaFamilyBackupMediaSetBackupetRestorefileRestorefilegroupRestorehistory

Restoring a Full Backup and a Differential BackupRestore a full backup.Restoring a differential.The WITH RECOVERY/NORECOVERY clause.Files must be restored in order.

The Restore StatementRESTORE DATABASE { database_name | @database_name_var } [ FROM < backup_device > [ ,...n ] ] [ WITH [ RESTRICTED_USER ] [ [ , ] FILE = { file_number | @file_number } ] [ [ , ] PASSWORD = { password | @password_variable } ] [ [ , ] MEDIANAME = { media_name | @media_name_variable } ] [ [ , ] MEDIAPASSWORD = { mediapassword | @mediapassword_variable } ] [ [ , ] MOVE 'logical_file_name' TO 'operating_system_file_name' ] [ ,...n ] [ [ , ] KEEP_REPLICATION ] [ [ , ] { NORECOVERY | RECOVERY | STANDBY = undo_file_name } ] [ [ , ] { NOREWIND | REWIND } ] [ [ , ] { NOUNLOAD | UNLOAD } ] [ [ , ] REPLACE ] [ [ , ] RESTART ] [ [ , ] STATS [ = percentage ]

Restoring a Full Backup and TlogsMust restore files in orderProvides the ability to restore to a point in timeProvides the ability to restore to a marked transaction

Restore Log StatementRESTORE LOG { database_name | @database_name_var } [ FROM < backup_device > [ ,...n ] ] [ WITH [ RESTRICTED_USER ] [ [ , ] FILE = { file_number | @file_number } ] [ [ , ] PASSWORD = { password | @password_variable } ] [ [ , ] MOVE 'logical_file_name' TO 'operating_system_file_name' ] [ ,...n ] [ [ , ] MEDIANAME = { media_name | @media_name_variable } ] [ [ , ] MEDIAPASSWORD = { mediapassword | @mediapassword_variable } ] [ [ , ] KEEP_REPLICATION ] [ [ , ] { NORECOVERY | RECOVERY | STANDBY = undo_file_name } ] [ [ , ] { NOREWIND | REWIND } ] [ [ , ] { NOUNLOAD | UNLOAD } ] [ [ , ] RESTART ] [ [ , ] STATS [= percentage ] ] [ [ , ] STOPAT = { date_time | @date_time_var } | [ , ] STOPATMARK = 'mark_name' [ AFTER datetime ] | [ , ] STOPBEFOREMARK = 'mark_name' [ AFTER datetime ]

Point in Time RestoreAllows user to restore to a point before a failure or corrupt dataAllows user to restore without unwanted data

Restore to MarkSTOPATMARK: Transactions can be marked so that a restore can take you up to that marked transaction.

STOPBEFOREMARK: Restores can also restore up to but not including that mark.

Restoring FilegroupsRestored by restoring the specified filegroups and applying a previous log and the next transaction log to bring the database to a consistent state.

Using a Backup to Create a New DatabaseA new database can be created by using the backup from an existing database.This is made possible by using the with move statement which copies the data files and applies them to the new database.

Consistency in Backing Up the System DatabasesIt is important to consistently backup up the master database and the msdb databases.In a restore scenario the master database should be restored first and the msdb database should be restore next followed by the model.The user databases should be restored last.

DiscussionDisaster Recovery scenarios.Added input from user experience.Discussion/Comments