Transcript Unix System Admin

5. SQL Restore tasks
• Objectives
– Learn howto recover databases from disaster
• Contents
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View database and transaction log backup files
Perform a complete data restoration of a user database
Recover a database to a specified point in time
Restore a database to standby mode using
• Practicals
– Recover your databases
• Summary
Determining the Data Restoration Sequence
• msdb database, SQL Server 2000 records the details of the backup and
the restore history in the msdb database
– which devices or files the backup is stored on,
– Who performed the backup,
– and at what time.
• If the msdb database is damaged, you should restore the msdb database
from backup before you restore any user databases.
• Check what backups you have in the Management container, right click
and select properties or double click and view contents
• Use the transact SQL
RESTORE LABELONLY FROM gurka
RESTORE HEADERONLY FROM gurka
RESTORE FILELISTONLY FROM gurka
• If you do not have a recent backup of the msdb database or are restoring
to another SQL Server 2000 instance.
– read each backup file and add the information to the msdb database
– Restore msdb history
Retrieving Backup Media Information
To retrieve backup media information
1. Ensure that you are logged on to the server as Administrator.
2. In the SQL Server Enterprise Manager console tree, expand the default
instance, expand the Management container, and then click Backup. The
backup devices for this SQL Server 2000 instance are displayed in the
details pane.
3. In the details pane, right-click SSEMDBTLogBackup and then click
Properties. The Backup Device Properties – SSEMTLogBackup dialog
box appears displaying the filename associated with this backup device.
4. Click the View Contents button. The View Backup Media Contents dialog
box appears, displaying the contents of the SSEMTLogBackup device.
Details regarding three transaction log backup sets appear.
5. Switch to SQL Query Analyzer.
6. On the toolbar, click the Load SQL Script button. The Open Query File
dialog box appears.
RESTORE LABELONLY FROM gurka
7.
RESTORE HEADERONLY FROM gurka
RESTORE FILELISTONLY FROM gurka
Back up the transaction log without truncation
• Before you attempt to restore a backup to a database that is
still functioning, be sure to restrict user access to it.
• Disk is intact, software error/smartboy caused damage
– disk containing a data file failed,
– SQL Server 2000 installation failed
– recover data to an earlier point in time.
• If a disk containing a data file fails, SQL Server Enterprise
Manager will display the database containing the damaged
data file as suspect.
• If you discover you have a suspect database, you should
immediately back up the transaction log without truncation
before you attempt any restoration of your dat
Back up the transaction log without truncation, cont.
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If you discover you have a suspect
database
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Backing up the current transaction log
(using the Without Truncation option)
allows you to recover up to the point
of failure.
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Goto the Databases container,
right-click the suspect database in the details pane,
point to All Tasks,
and then click Restore Database.
Next, you should replace the failed disk.
If your data is using RAID for fault
tolerance, all that you need to do is to
simply add the new drive to the
RAID system.
Begin restoration suspect Database
1. Goto the Databases container,
2. right-click the suspect database in
the details pane,
3. point to All Tasks,
4. and then click Restore Database.
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the First Backup To Restore dropdown list allows you to select
which backup to try first
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You can make a combination of
backup sets that you can use to
complete the restoration.
Howto restore suspect Database
1. Goto the Databases container,
2. right-click the suspect database in the
details pane,
3. point to All Tasks,
4. and then click Restore Database.
5. Select options tab
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You can choose to leave the database
operational, not possible to restore
additional transaction logs.
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You can choose to leave the database
read-only and able to restore
additional transaction log files.
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You can leave database read only adn
able to restore more transaction logs
Restoring a Data File or Filegroup
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This you use to restore from a
selectable file to retireve certain
data from that backup.
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Restoring from a subset of files
Restoring to a Different SQL Server 2000
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When restoring a database to a second SQL Server you must first:
– create the database in SQL Server into which you will restore the database
– Generally, you should use the same database name and database file paths as the
one you are restoring
– If you choose a different name, you will have to select the Force Restore Over Existing
Database
– if you choose to restore to a different physical path, you will need to adjust the
restoration path for the database files
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After you have created the database in the SQL Server:
1. begin by right-clicking the database in the console
tree for the SQL Server 2000 instance that
you want to restore
2. pointing to All Tasks, and then clicking
Restore Database
3. the General tab of the Restore Database dialog box,
4. click the From Device option button
5. Next, you need to click the Select Devices button to
select a backup device from which to restore data
Restoring to a Different SQL Server 2000
6. Choose Restore Devices dialog box,
7. click the Add and select a file or tape drive from which to restore data
Restoring to a Different SQL Server 2000
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After you select a file or tape drive from which to restore data, you can
choose among several options.
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you can restore a
specified backup set
– recover or leave the database
able to restore additional
transaction logs
– you can choose to read the
backup set
information from a specified
device
– add it to the backup history
in the msdb database
Recovery of a Database to a Point in Time
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This is very useful if you need to rollback to a certain point in time.
Standby mode allows you to view the condition of the database at the
end of each restoration before you apply additional transaction log files.
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With Transact SQL you can restore to a named mark.
Do not start use the database before carefully verify and checking time
restored data
Performing Restorations Using Transact-SQL
• You can restrict access to the newly restored database to
database administrators as part of the restore process.
• You can move a database to a new location using the MOVE
option.
• You can supply a password.
• You can restart an interrupted restore.
• You can recover to a named mark.
• Cons, they need experience and practise.
Restoring a Complete Database
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The RESTORE DATABASE and RESTORE LOG commands can be very
simple or very complex.
RESTORE DATABASE Northwind FROM DISK = 'C:\SQLBackups\Temp.bak
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The preceding example restores a full database backup of the Northwind
database from the C:\SQLBackups\Temp.bak file on disk.
RESTORE DATABASE Northwind FROM NorthwindFullBackup WITH NORECOVERY RESTORE
DATABASE Northwind FROM NorthwindDiffBackup WITH FILE = 2, NORECOVERY RESTORE
LOG Northwind FROM NorthwindTLogBackup WITH FILE = 4, NORECOVERY RESTORE LOG
Northwind FROM NorthwindTLogBackup2 WITH FILE = 5
Restoring a Data File or Filegroup
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Database Northwind is restored from file backup
Backup set 2 is used
A notification is made after each 25%
Only Admin has access to database after restore
Restore of transaction log is also performed with backup set 2
RESTORE DATABASE Northwind FILE = 'Second_Data_File'
FROM File_Backup WITH RESTRICTED_USER, NORECOVERY, STATS = 25
RESTORE LOG Northwind FROM NorthwindTLogBackup WITH FILE = 2
Restoration Using the Move Option
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This restores the full database backup
The database files is moved to a new disk location
A media password is added
Restore of transaction log is also performed
RESTORE DATABASE Northwind FROM NorthwindFullBackup WITH
NORECOVERY , MEDIANAME = 'NorthwindBackups' ,
MEDIAPASSWORD = 'my_password' ,
MOVE = 'Northwind' TO 'D:\SQLDATA\NwindNew.mdf' ,
MOVE = 'NorthwindLog' TO 'E:\SQLLogs\NwindNewLog.ldf' ,
RESTORE LOG Northwind FROM NorthwindTLogBackup
Restoring to Standby Mode
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This restores the full database backup
Two transaction logs are restored
After restore the database is set in standby mode
RESTORE DATABASE Northwind FROM NorthwindFullBackup WITH NORECOVERY
RESTORE LOG Northwind FROM NorthwindTLogBackup WITH FILE = 4 , NORECOVERY
RESTORE LOG Northwind FROM NorthwindTLogBackup WITH FILE = 5 ,
STANDBY = TO 'D:\SQL\UNDO.tmp'
Restoring to a Specified Point in Time
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This restores the full database backup
Two transaction logs are restored
The restore is stopped when a stopdate is reached.
RESTORE DATABASE Northwind FROM NorthwindFullBackup WITH NORECOVERY
RESTORE LOG Northwind FROM NorthwindTLogBackup WITH FILE = 4 , NORECOVERY
RESTORE LOG Northwind FROM NorthwindTLogBackup WITH FILE = 5 , RECOVERY,
STOPAT = 'Oct 2, 2000 5:08:32 PM'
Restoring the Master Database
• We will take a closer look on
– Restore the master database from backup
– Rebuild the system databases
• If master database is corrupted or destroyed, you will lose
you entire SQL Server installation because it uses the
databases for configurations
• you can restore the master database using the most recent
full database backup of the master database
• You should also mirror the system databases using RAID 1
where possible.
Restoring the Master Database
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To restore the master database, start SQL Server 2000 in single-user
mode with the –m option in the Command Prompt window or from the Run
dialog box. You must first stop the database.
C:\> sqlservr –m
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Next, start SQL Query Analyzer and restore your most recent backup of
the master database using the same commands you use to restore any
user database.
RESTORE DATABASE master FROM MasterFullBackup
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After the restoration of the
master database is complete,
the SQL Server running in
single-user mode will stop.
You can then restart SQL
Server 2000.
Rebuilding the System Databases
• To rebuild the system databases, use the Rebuildm.exe utility
C:\Program Files\Microsoft SQL Server\80\Tools\Binn
C:\Program Files\Microsoft SQL Server\mssql\Binn
• Remove the Read-only attribute from the original installation
files, or the Rebuildm utility will fail.
• Click the Rebuild button to begin
the process. You receive a warning
in a Rebuild Master dialog box
that you are about to rebuild
and overwrite all of your system databases