Are you tired of manually restoring each
database on a new server when the original server has a melt down?
Does the manual process seem slow, and prone to keystoke and mouse click
errors? Would you like to have
those restore scripts automatically built, so you only have to fire them
off? Well this article will
show you one possible method for speeding up and reducing errors will trying
to perform a restore of all databases on a server.
Most DBAs develop procedures on how to
recovery a server, should it fail.
Some organizations are lucky enough to have the necessary hardware/software
to support a standby server, and perform log shipping to minimize downtime.
Not all organizations can financially support the standby server model.
Our shop happens to be one of those, fund starved, organizations.
Just like any other organization our goal is to recover any failed server as
quick as possible, given the tools and hardware we have to work with.
Therefore we have developed two stored procedures to help speed up our
recovery time. One
stored procedure (SP) identifies the database backup files that need to be
restored from tape, while the other the SP builds a restore script. The goal of these two SPs is to minimize the time and errors associated
with rebuilding our database servers.
Overview of Stored Procedures
The two SPs we have built to help with
disaster recovery are usp_build_restore_script, and
usp_what_files_to_restore. The
"usp_build_restore_script" SP builds a restore script, which contains
RESTORE DATABASE and RESTORE LOG commands for each database on a server,
where as the "usp_what_files_to_restore" SP produces a list of backup files
that need to be restored from tape, which are required by the restore
script.
Each of these SPs take into account which
backup files are associated with the current backup set.
Meaning the set of backup files needed to restore each database from the
last full backup. The restore script produced will recover all databases to
the point of the last backup.
Why We Built These Stored Procedures
Like most shops we decided we where going
to practices recovering one of our production servers, so we scheduled a
disaster recovery test. During
our first disaster recovery exercise we identified two things that could be
improved. One was reducing the
time it took restoring database backups from tape, and the other was
reducing the time and manual effort associated with restoring all databases.
Our first disaster recovery exercise
restored the entire backup directory that contained two weeks worth of
database backup files. Normally
our database recovery would only require the most recent set of backups (one
full, one differential, and/or a few transaction log backups). Every extra file that was unnecessarily restored from tape increased the
total time it took to copy the database backups from tape, and therefore
increased the downtime. Our
goal was to minimize down time.
To optimize the tape restore time, we developed the
"usp_what_files_to_restore" SP to identify a specific set of database backup
files associated with the lastest backup cycle (full, diff, and transaction
logs) that needed to be recovered.
Secondly we noticed that restoring the
databases one at a time manually using Enterprise Manager was a slow, and
error prone process. This
manual restore process could easily be automated to reduce the duration and
errors associated with performing manual database restores.
This lead us to develop "usp_build_restore_script" SP to produce a database
restore script that would restore every database on a server.
The generated database restore script would streamline the restore process
by replacing the manual database restores, done via Enterprise Manager.
Details of the SPs
The code for each of these SPs can be
found at the bottom of this article.
I’m not going to review the code in detail, but will generally describe
where the code gets the backup information, and how that backup information
is used.
These SPs can be broken up into sections
and subsection. For each
section or subsection mentioned below refer to the SPs, at the end of this
article, to find the code associated with referenced sections.
There are two sections in each SP.
Section 1 collects database backup file information, and section 2 uses the
backup information to produce the desired database restore script or list of
files to restore from tape.
"Section 1" is basically the same for both
SPs. This section uses the
information stored in the
backupset, backupmediaset, and backupmediafamily system tables, in the
"msdb" database, to gather the physical file names and backup types
(full, differential, and log) for each database backup.
This section does this in three different subsections, 1A, 1B, and 1C, where
each subsection is processed in order for each database.
"Subsection 1A" is responsible for determining physical file name for the
last full backup. "Subsection
1B" finds the name of the last differential backup, and "Subsection 1C"
determines the physical names of all the transaction log backups taken since
the last differential backup.
Each of these subsections place the physical backup names in a temporary
table named ##backupnames.
"Section 2" is responsible to produce that actual restore script or the
report of physical backup files to restore from tape.
In "usp_build_restore_script" SP, section 2
processes through the temporary table ##backupnames one database at a time,
in the order in which were taken (full, diff, then transaction logs).
For each database a series of "PRINT" TSQL commands are executed to output
the actual database "RESTORE" commands, with the full database restore being
first, then the differential, and then any transaction logs being last.
If a given database requires multiple "RESTORE" commands, then the
"NORECOVERY" option is specified on all the "RESTORE’ commands except the
very last one. This allows
multiple backups to be restored, and to have recovery performed once after
the last backup for each database is precessed.
Since the "master" database needs to be restored in single user mode, the
restore script produced contains the commands to restore the "master"
database, but they are commented out.
This is so the restore script can be run, as is, to restore all databases,
except the "master" database.
Also this allows you to highlight and run the restore commands for the
"master" database.
Section 2 for
"usp_what_files_to_restore" SP also processes through temporary table
##backupnames. For each
physical database backup this SP produces a TSQL "PRINT" statement that
outputs just the physical database backup name.
How these SPs are executed
Each SPs basically only produces a report.
The reports generated needs be directed to physical files.
This is accomplished by executing these SP using the "osql" command.
Here are the commands I use for redirect the output from each of these SPs
to a file:
osql -E -Smyserver -Q"dba.dbo.usp_build_restore_script" -o c:\mssql\restore\restore_all.sql -w200 osql -E -Smyserver -Q"dba.dbo.usp_what_files_to_restore" -o c:\mssql\restore\files_to_restore.txt -w200
I have added two steps, that execute these commands, in our SQL Server agent
job that creates our database backups.
In addition I have added a step to the same backup job to copy the restore
script and restore file list to another server on a network.
This makes sure we have a copy of the script and list of files to restore on
another server, should our SQL Server box crash.
Here is a sample of the TSQL commands
produced by "usp_build_restore_script" on a server that contained only a
single user database.
Restore Script
-- Restore All databases restore database DBA from disk = 'C:\mssql\MSSQL\BACKUP\DBA_20021005_2000_full.bak' with replace, norecovery go restore database DBA from disk = 'C:\mssql\MSSQL\BACKUP\DBA_20021006_2000_diff.bak' with replace, norecovery go restore log DBA from disk = 'C:\mssql\MSSQL\BACKUP\DBA_20021007_1000_tran.bak' with replace, norecovery go restore log DBA from disk = 'C:\mssql\MSSQL\BACKUP\DBA_20021007_1200_tran.bak' with replace go /* restore database master from disk = 'C:\mssql\MSSQL\BACKUP\master_20021006_2000_full.bak' with replace */go restore database model from disk = 'C:\mssql\MSSQL\BACKUP\model_20021006_2000_full.bak' with replace go restore database msdb from disk = 'C:\mssql\MSSQL\BACKUP\msdb_20021006_2000_full.bak' with replace go restore database Northwind from disk = 'C:\mssql\MSSQL\BACKUP\Northwind_20021006_2000_full.bak' with replace go restore database pubs from disk = 'C:\mssql\MSSQL\BACKUP\pub_20021006_2000_full.bak' with replace go
Here is also a copy of the files to restore
from tape created by "usp_what_files to restore" from the same server.
Files to Restore
C:\mssql\MSSQL\BACKUP\DBA_20021005_2000_full.bak C:\mssql\MSSQL\BACKUP\DBA_20021006_2000_diff.bak C:\mssql\MSSQL\BACKUP\DBA_20021007_1000_tran.bak C:\mssql\MSSQL\BACKUP\DBA_20021007_1200_tran.bak C:\mssql\MSSQL\BACKUP\master_20021006_2000_full.bak C:\mssql\MSSQL\BACKUP\model_20021006_2000_full.bak C:\mssql\MSSQL\BACKUP\msdb_20021006_2000_full.bak C:\mssql\MSSQL\BACKUP\Northwind_20021006_2000_full.bak C:\mssql\MSSQL\BACKUP\pubs_20021006_2000_full.bak
Conclusion
Hopefully this article gave you an idea on
how I streamlined our recovery process. If you are currently restoring your
databases manually, then you should consider implementing procedures that
will speed up and reduce possible errors during a database server recovery.
Implementing an automated script building approach like I have suggested,
will not only save you time, but will reduce your anxiety level, during an
already stressful disaster recovery situation.
Code for usp_build_restore_script
SET QUOTED_IDENTIFIER OFF GO SET ANSI_NULLS ON GO create procedure usp_build_restore_script as -- -- This stored procedure was written by Greg Larsen for Washington State Department of Health. -- Date: 12/16/2001 -- -- Description: -- This stored procedure generates TSQL script that will restore all the databases -- on the current SQL Server. This stored procedure takes into account when the last -- full and differential backups where taken, and how many transaction log backups -- have been taken since the last database backup, based on the information in -- the msdb database. -- -- Modified: -- -- -- Declare variables used in SP declare @cmd nvarchar (1000) declare @cmd1 nvarchar (1000) declare @db nvarchar(128) declare @filename nvarchar(128) declare @cnt int declare @num_processed int declare @name nvarchar(128) declare @physical_device_name nvarchar(128) declare @backup_start_date datetime declare @type char(1) -- Turn off the row number message set nocount on -- SECTION 1 ---------------------------------------------- -- Define cursor to hold all the different databases for the restore script will be built declare db cursor for select name from master..sysdatabases where name not in ('tempdb') -- Create a global temporary table that will hold the name of the backup, the database name, and the type of database backup. create table ##backupnames ( name nvarchar(100), database_name nvarchar(100), type char(1) ) -- Open cursor containing list of database names. open db fetch next from db into @db -- Process until no more databases are left WHILE @@FETCH_STATUS = 0 BEGIN -- Subsection 1A -------------------------------------------- -- initialize the physical device name set @physical_device_name = '' -- get the name of the last full database backup select @physical_device_name = physical_device_name , @backup_start_date = backup_start_date from msdb..backupset a join msdb..backupmediaset b on a.media_set_id = b.media_set_id join msdb..backupmediafamily c on a.media_set_id = c.media_set_id where type='d' and backup_start_date = (select top 1 backup_start_date from msdb..backupset where @db = database_name and type = 'd' order by backup_start_date desc) -- Did a full database backup name get found if @physical_device_name <> '' begin -- Build command to place a record in table that holds backup names select @cmd = 'insert into ##backupnames values (' + char(39) + @physical_device_name + char(39) + ',' + char(39) + @db + char(39) + ',' + char(39) + 'd' + char(39)+ ')' -- Execute command to place a record in table that holds backup names exec sp_executesql @cmd end -- Subsection 1B -------------------------------------------- -- Reset the physical device name set @physical_device_name = '' -- Find the last differential database backup select @physical_device_name = physical_device_name, @backup_start_date = backup_start_date from msdb..backupset a join msdb..backupmediaset b on a.media_set_id = b.media_set_id join msdb..backupmediafamily c on a.media_set_id = c.media_set_id where type='i' and backup_start_date = (select top 1 backup_start_date from msdb..backupset where @db = database_name and type = 'I' and backup_start_date > @backup_start_date order by backup_start_date desc) -- Did a differential backup name get found if @physical_device_name <> '' begin -- Build command to place a record in table that holds backup names select @cmd = 'insert into ##backupnames values (' + char(39) + @physical_device_name + char(39) + ',' + char(39) + @db + char(39) + ',' + char(39) + 'i' + char(39)+ ')' -- Execute command to place a record in table that holds backup names exec sp_executesql @cmd end -- Subsection 1C -------------------------------------------- -- Build command to place records in table to hold backup names for all -- transaction log backups from the last database backup set @CMD = 'insert into ##backupnames select physical_device_name,' + char(39) + @db + char(39) + ',' + char(39) + 'l' + char(39) + 'from msdb..backupset a join msdb..backupmediaset b on a.media_set_id = b.media_set_id join ' + 'msdb..backupmediafamily c on a.media_set_id = c.media_set_id ' + 'where type=' + char(39) + 'l' + char(39) + 'and backup_start_date > @backup_start_dat and' + char(39) + @db + char(39) + ' = database_name' -- Execute command to place records in table to hold backup names -- for all transaction log backups from the last database backup exec sp_executesql @cmd,@params=N'@backup_start_dat datetime', @backup_start_dat = @backup_start_date -- get next database to process fetch next from db into @db end -- close close db -- Section B ---------------------------------------------- open db -- Get first recod from database list cursor fetch next from db into @db -- Generate Heading in Restore script print '-- Restore All databases' -- Process all databases WHILE @@FETCH_STATUS = 0 BEGIN -- define cursor for all database and log backups for specific database being processed declare backup_name cursor for select name,type from ##backupnames where database_name = @DB -- Open cursor containing list of database backups for specific database being processed open backup_name -- Determine the number of different backups available for specific database being processed select @CNT = count(*) from ##backupnames where database_name = @DB -- Get first database backup for specific database being processed fetch next from backup_name into @physical_device_name, @type -- Set counter to track the number of backups processed set @NUM_PROCESSED = 0 -- Process until no more database backups exist for specific database being processed WHILE @@FETCH_STATUS = 0 BEGIN -- Increment the counter to track the number of backups processed set @NUM_PROCESSED = @NUM_PROCESSED + 1 -- Is the number of database backup processed the same as the number of different backups -- available for specific database being processed? if @CNT = @NUM_PROCESSED -- If so, is the type of backup currently being processed a transaction log backup? if @TYPE = 'l' -- build restore command to restore the last transaction log select @cmd = 'restore log ' + rtrim(@db) + char(13) + ' from disk = ' + char(39) + rtrim(substring(@physical_device_name,1,len(@physical_device_name))) + char(39) + char(13) + ' with replace' else -- Last backup was not a transaction log backup -- Build restore command to restore the last database backup select @cmd = 'restore database ' + rtrim(@db) + char(13) + ' from disk = ' + char(39) + rtrim(substring(@physical_device_name,1,len(@physical_device_name))) + char(39) + char(13) + ' with replace' else -- Current backup is not the last backup -- Is the current backup being processed a transaction log backup? if @TYPE = 'l' -- Build restore command to restore the current transaction backup, with no recovery select @cmd = 'restore log ' + rtrim(@db) + char(13) + ' from disk = ' + char(39) + rtrim(substring(@physical_device_name,1,len(@physical_device_name))) + char(39) + char(13) + ' with replace, norecovery' else -- Current backup being processed is not a transaction log backup -- Build restore command to restore the currrent database backup, with no recovery select @cmd = 'restore database ' + rtrim(@db) + char(13) + ' from disk = ' + char(39) + rtrim(substring(@physical_device_name,1,len(@physical_device_name))) + char(39) + char(13) + ' with replace, norecovery' -- if it is master comment line out if @db = 'master' set @cmd = '/* ' + char(13) + @cmd + char(13) + '*/' -- Generate the restore command and other commands for restore script print @cmd print 'go' print ' ' -- Get next database backup to process fetch next from backup_name into @physical_device_name, @type end -- Close and deallocate database backup name cursor for current database being processed close backup_name deallocate backup_name -- Get next database to process fetch next from db into @db end -- Close and deallocate cursor containing list of databases to process close db deallocate db -- Drop global temporary table drop table ##backupnames GO SET QUOTED_IDENTIFIER OFF GO SET ANSI_NULLS ON GO
Code for usp_build_list_of_files
SET QUOTED_IDENTIFIER OFF GO SET ANSI_NULLS ON GO CREATE procedure usp_what_files_to_restore as -- -- -- This stored procedure was written by Greg Larsen for Washington State Department of Health. -- Date: 02/28/2002 -- -- Description: -- This stored procedure generates a list of files that need to be restored -- should the server need to be rebuild. The list only contains a list of database -- backup files. -- -- Declare variables used in SP declare @cmd nvarchar (1000) declare @cmd1 nvarchar (1000) declare @db nvarchar(128) declare @filename nvarchar(128) declare @cnt int declare @num_processed int declare @name nvarchar(128) declare @physical_device_name nvarchar(128) declare @backup_start_date datetime declare @type char(1) -- Section A -------------------------------------------- -- Turn off the row number message set nocount on -- Define cursor to hold all the different databases for the restore script will be built declare db cursor for select name from master..sysdatabases where name not in ('tempdb') -- Create a global temporary table that will hold the name of the backup, the database name, -- and the type of database backup. create table ##backupnames ( name nvarchar(100), database_name nvarchar(100), type char(1) ) -- Open cursor containing list of database names. open db fetch next from db into @db -- Process until no more databases are left WHILE @@FETCH_STATUS = 0 BEGIN -- Subsection 1A ---------------------------------------------- -- initialize the physical device name set @physical_device_name = "" -- get the name of the last full database backup select @physical_device_name = physical_device_name , @backup_start_date = backup_start_date from msdb..backupset a join msdb..backupmediaset b on a.media_set_id = b.media_set_id join msdb..backupmediafamily c on a.media_set_id = c.media_set_id where type='d' and backup_start_date = (select top 1 backup_start_date from msdb..backupset where @db = database_name and type = 'd' order by backup_start_date desc) -- Did a full database backup name get found if @physical_device_name <> "" begin -- Build command to place a record in table that holds backup names select @cmd = 'insert into ##backupnames values (' + char(39) + @physical_device_name + char(39) + ',' + char(39) + @db + char(39) + "," + char(39) + 'd' + char(39)+ ')' -- Execute command to place a record in table that holds backup names exec sp_executesql @cmd end -- Subsection 1B ---------------------------------------------- -- Reset the physical device name set @physical_device_name = "" -- Find the last differential database backup select @physical_device_name = physical_device_name, @backup_start_date = backup_start_date from msdb..backupset a join msdb..backupmediaset b on a.media_set_id = b.media_set_id join msdb..backupmediafamily c on a.media_set_id = c.media_set_id where type='i' and backup_start_date = (select top 1 backup_start_date from msdb..backupset where @db = database_name and type = 'I' and backup_start_date > @backup_start_date order by backup_start_date desc) -- Did a differential backup name get found if @physical_device_name <> "" begin -- Build command to place a record in table that holds backup names select @cmd = 'insert into ##backupnames values (' + char(39) + @physical_device_name + char(39) + ',' + char(39) + @db + char(39) + "," + char(39) + 'i' + char(39)+ ')' -- Execute command to place a record in table that holds backup names exec sp_executesql @cmd end -- Subsection 1B ---------------------------------------------- -- Build command to place records in table to hold backup names for all -- transaction log backups from the last database backup set @CMD = "insert into ##backupnames select physical_device_name," + char(39) + @db + char(39) + "," + char(39) + "l" + char(39) + "from msdb..backupset a join msdb..backupmediaset b on a.media_set_id = b.media_set_id " + "join msdb..backupmediafamily c on a.media_set_id = c.media_set_id " + "where type=" + char(39) + "l" + char(39) + "and backup_start_date > @backup_start_dat and" + char(39) + @db + char(39) + " = database_name" -- Execute command to place records in table to hold backup names -- for all transaction log backups from the last database backup exec sp_executesql @cmd,@params=N'@backup_start_dat datetime', @backup_start_dat = @backup_start_date -- get next database to process fetch next from db into @db end -- close and deallocate database list cursor close db deallocate db -- Section B ------------------------------------------------------- -- define cursor for all database and log backups declare backup_name cursor for select name,type from ##backupnames -- Open cursor containing list of database backups for specific database being processed open backup_name -- Get first database backup for specific database being processed fetch next from backup_name into @physical_device_name, @type -- Set counter to track the number of backups processed set @NUM_PROCESSED = 0 -- Process until no more database backups exist for specific database being processed WHILE @@FETCH_STATUS = 0 BEGIN -- print file name to restore print @physical_device_name -- Get next database backup to process fetch next from backup_name into @physical_device_name, @type end -- Close and deallocate database backup name cursor for current database being processed close backup_name deallocate backup_name -- Drop global temporary table drop table ##backupnames GO SET QUOTED_IDENTIFIER OFF GO SET ANSI_NULLS ON GO