Common SQL Server Backup Problems

Grant Fritchey | www.ScaryDBA.com

www.ScaryDBA.com

Common Backup

Problems

Grant Fritchey, Red Gate Software


Goals

Identify common backup issues

Prevent those issues from occurring

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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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[email protected] www.scarydba.com

@gfritchey www.linkedin.com/in/scarydba

Grant FritcheyProduct Evangelist, Red Gate Software

http://www.microsoft.com/sqlserverlabs





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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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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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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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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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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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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Goals

Identify common backup issues

Prevent those issues from occurring

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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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http://www.simple-talk.com/sql/database-administration/7-preventable-backup-errors/

http://www.simple-talk.com/sql/database-administration/sql-server-backup-and-restore-for-the-accidental-dba/

http://www.simple-talk.com/sql/backup-and-recovery/sql-server-2005-backups/


Questions?

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Common SQL Server Backup Problems

Software

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