Common SQL Server Backup Problems
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Transcript of Common SQL Server Backup Problems
Grant Fritchey | www.ScaryDBA.com
www.ScaryDBA.com
Common Backup
Problems
Grant Fritchey, Red Gate Software
Grant Fritchey | www.ScaryDBA.com
Goals
Identify common backup issues
Prevent those issues from occurring
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Grant Fritchey | www.ScaryDBA.com
Agenda
SQL Server Backups
File Backups
Drive Space
Full Transaction Log
Network Backups
Differential Only
Broken Backup Chain
The Wrong Server
Backup Load
Backup Testing
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Grant Fritchey | www.ScaryDBA.com
[email protected] www.scarydba.com
@gfritchey www.linkedin.com/in/scarydba
Grant FritcheyProduct Evangelist, Red Gate Software
Grant Fritchey | www.ScaryDBA.com
SQL Server Backups
Complete copy of the database» Not an export» Not a script» Not a file copy
Principal means of protecting the business data
Multiple Backup Types» Full» Differential» File/FileGroup» Log» Partial
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Grant Fritchey | www.ScaryDBA.com
File Backups
Indications» File backup only» Expected restore from .MDF & .LDF files
Cause» SQL Server locks the files while they’re in use
Remedy» Run a real backup» Stop the server, copy the files, start the server
(and no, I’m not serious)
Emergency» Try using ATTACH, but don’t hold out hope
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Grant Fritchey | www.ScaryDBA.com
Drive Space
Indications» Errors on backup» Alerts on drive space» No backups available
Cause» Not monitoring drive space» Database size increased
Remedy» Monitor your drive space» Clean up backups» Monitor database size
Emergency» If the backup failed, no options
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Full Transaction Log
Indications» Log files constantly growing» Transaction errors caused by full file
Cause» Log backups failed» Log backups never implemented
Remedy» Set up scheduled log backups» If FULL RECOVERY not needed, switch to SIMPLE
Emergency» Attach an additional log file
— Not always possible
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Network Backups
Indications» Backups extremely slow» Timeout on backups» Resource contention on server
Cause» Backing up across network instead of through
dedicated fiber channel
Remedy» Backup to “local” drive» If needed backup locally then copy the file
Emergency» Do it anyway
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Differential Only
Indications» Error, no files ready to roll forward
Cause» No FULL restore run» Full restore run, but database recovered
Remedy» Run a FULL restore» Use WITH NORECOVERY on restore» Make sure you have a FULL backup
Emergency» With no full backup, no options
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Grant Fritchey | www.ScaryDBA.com
Broken Backup Chain
Indications» Error: Database has not been restored to the correct
earlier state Cause
» Wrong Full backup» Extra Full backup taken
Remedy» Use correct Full backup» Use SNAPSHOT» Use COPY_ONLY
Emergency» If you have all the log backups, you can use those
instead
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The Wrong Server
Indications» Phone is ringing
Cause» Ran a restore on wrong server» Used WITH ROLLBACK IMMEDIATE
Remedy» Use different security for production» Color code production servers» Don’t use ROLLBACK IMMEDIATE
Emergency» Yes it is
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Grant Fritchey | www.ScaryDBA.com
Backup Load
Indications
» Excessive CPU or I/O contention
» Waits on backups
» Blocking
Cause
» Excessive load on server makes backups difficult
Remedy
» Backup from AlwaysOn
Emergency
» Do what you must
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Grant Fritchey | www.ScaryDBA.com
Backup Testing
“You’re only as good as your last restore” Kimberly Tripp (as far as I can determine)
DBCC» Against Production» Against a Backup
CHECKSUM» Added overhead
VERIFYONLY» Header only without checksum
RESTORE» Like nuking from orbit, the only way to be sure
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Grant Fritchey | www.ScaryDBA.com
Goals
Identify common backup issues
Prevent those issues from occurring
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Grant Fritchey | www.ScaryDBA.com
Resources
Scarydba.com/backup
Preventable Backup Errors: http://www.simple-talk.com/sql/database-administration/7-preventable-backup-errors/
Backup and Restore for the Accidental DBA: http://www.simple-talk.com/sql/database-administration/sql-server-backup-and-restore-for-the-accidental-dba/
SQL Server Backups: http://www.simple-talk.com/sql/backup-and-recovery/sql-server-2005-backups/
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Questions?
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