Firebird database recovery and protection for enterprises and ISV
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This document discusses database reliability and recovery for Firebird databases. It begins by addressing whether Firebird databases are reliable, noting that all databases can experience corruption from hardware or software failures over time. The document then discusses what happens when a Firebird database crashes, explaining that the database consists of system metadata pages and user data pages. It provides an overview of standard recovery methods using gfix and gbak commands. Additional approaches for recovery are presented, including the FBDataGuard and FirstAID tools from IBSurgeon. Offers are made to developers for subscribing to FBDataGuard instances to protect databases.
![Example of backup problem alert
• Job backup@[ server-0000 / db-0000 ] malfunction
• Unexpected job backup@[ server-0000 / db-0000 ] error:
There is not enough space on the disk](https://image.slidesharecdn.com/firebirdrecoveryandprotection-111229054833-phpapp01/85/Firebird-database-recovery-and-protection-for-enterprises-and-ISV-32-320.jpg)
Firebird database recovery and protection for enterprises and ISV
- 1. Firebird databases recovery and protection for enterprises and ISVs Alexey Kovyazin, IBSurgeon
- 2. About IBSurgeon • Tools and consulting • Platinum Sponsor of Firebird Foundation • Founded in 2002: 9 years of Firebird and InterBase recoveries and consulting • Based in Moscow, Russia www.ib-aid.com www.ibsurgeon.com
- 3. Agenda 1. Is Firebird reliable? 2. What happens when database crashes 3. Standard means to recover database • Tips and tricks 4. Approaches for recovery • FBDataGuard approach • FirstAID approach 5. Offer for developers
- 5. Is database corruption a problem only for Firebird? • All databases are being corrupted from time time: • MSSQL www.google.com/search?q=MSSQL+database+corruption - Oracle - http://www.google.com/search?q=Oracle+database+corruption - MySQL, MS Access, DB2, Sybase, etc, etc (and InterBase)
- 6. Corruption is a matter of statistics • HDD fails • RAM fails • … • Automobiles fail • Electronics fails • Space shuttles fall The same is for hardware & software combination we use with Firebird
- 7. How to live in “corruptions” world? 1. This is impossible to exclude (prevent) corruption at all (if you are not God) 2. Realistic approach is to decrease the chance of corruption – i.e., increase system stability, Common reliability levels are: 99%, 99.5%, 99,9%, 99.99%, etc
- 8. Examples of reliability • It’s 3 days stop of •99% your business (e.g., December 23- 25 ) •99,5% • About 1 day stop •99,9% • 3.5 hours stop •99,99% • 20 minutes
- 9. Why Firebird corrupted? % 60 50 40 30 20 10 0 %
- 10. How to achieve 99,5% Firebird stability? • Buy good hardware with RAID • Perform backup/restore every day It’s much easier and cheaper to achieve 99,5% reliability for Firebird than for other databases. Yes, Firebird is reliable!
- 11. But it happens… • No backups • No administrator • Serious hardware fails • Big database and 24/7 workmode – can’t do backup/restore everyday • What to do?
- 12. WHAT HAPPENS WHEN DATABASE CRASHES?
- 13. Firebird inside looks like a forest… Database System User’s metadata data Data Index Data Index pages pages pages pages
- 14. …with only 2 trees • System data pages • Contains information about tables, indices, stored procedures. This information is used to store and read user data pages • User data pages • Contains actual users data • Indices? • Indices always can be recreated • System indices can be a problem
- 15. What corruption means for Firebird? • For some reason Firebird engines cannot read one or several pages and fails to build database image • For HDD corruptions - many pages • RAM corruptions – few pages Corruptions appear at: 1. Users screen (“internal Firebird software consistency check” error message) 2. In firebird.log
- 16. Heavy and Easy corruptions • Easy corruptions • Users data are corrupted (partially) • User’s indices corrupted • Heavy corruptions • System data are damaged (We can’t read users data!)
- 17. STANDARD MEANS TO RECOVER DATABASE
- 18. Standard way to recover • Stop Firebird server. • Make a copy of Firebird database. • Start Firebird server and run the following commands: gfix.exe -v -full gfix.exe -mend –ig gbak -b –g -v • If backup completed successfully, restore database: gbak -c -v -user SYSDBA -pass masterkey path_to_backup path_to_database
- 19. Tips 1. Try to run them all, even if gfix shows errors. 2. Always use switch –ig for gbak to ignore checksum errors 3. Always use switch –g for gbak to suppress garbage collection (and to workaround index errors) 4. Use –v switch to have detailed output
- 20. Restore errors • After fixing corruptions it's a often to see "Cannot commit index" error at restore step. • In Firebird 2.0 and later this comes as a warning and database will be not brought on-line • 1) IBDataPump (free tool) http://www.clevercomponents.com/demo/datapump/IBPu mp.zip 2) Create only metadata database • gbak -c -m • 3) Run IBDataPump and set partially repaired database as Source, and fresh empty database as target
- 21. Effectiveness • Gbak+Gfix can recover almost all easy corruptions • What they cannot do: • Heavy corruptions with a lot of losses • System data corruptions
- 22. IBSURGEON TOOLS
- 23. Metadata repository METADATA Copy in repository User tables Keeps copy of raw metadata Indices BLOBS
- 24. FBDataGuard Metadata FBDataGuard Extractor extracts all possible data New database User BLOBs
- 25. Demo
- 26. Up to 99% of successful recoveries!
- 27. And also • FBDataGuard does monitoring and health checks • Backups and maintenance schedule • 26 parameters to check • Email alerts • Web-console
- 28. Example with TEMP FBDataGuard found the temp files size = N Not enough Not space – enough administrator will space have alert and M – N<X recommendation Free space at to increase TEMP- locations TEMP =M
- 29. Example alert Too big temporary files Total size of all temporary files 3 Gb is more than recommended: 500 Mb Firebird creates temporary files for some SQL queries (PLAN SORT). Too big size of temporary files can indicate performance problems. This is not a strictly defined number, so this threshold depends on particular database and application.
- 30. Index problem example non-activated FBDataGuard indices usually found non- Administrator will indicates get alert and activated index recommendation to after restore corruption check indices (missed Foreign Keys) Possible perfomance problem prevented!
- 31. Example of backup problem resolution FBDataGuard found the backup size = M Not Backup cancelled, database enough status is set to space Critical, administrato M>=N r got alert FBDataGuard found free space Corruption of at backups’ disk = backup was N prevented!
- 32. Example of backup problem alert • Job backup@[ server-0000 / db-0000 ] malfunction • Unexpected job backup@[ server-0000 / db-0000 ] error: There is not enough space on the disk
- 33. Example of good backup notification
- 34. Hardware and UNDELETE failures • HDD corruption • Flash-drive corruption • UNDELETE problem
- 35. FBFirstAID • If we don’t have copy of system metadata (i.e., FBDataGuard) • Trying to recover data • Must be combined with standard tools • 3.0 version to be released at January 2012! • Successful recovery chances – 80%
- 36. Offers for ISVs • To protect databases we offer 1 year subscription to install as many as you need FBDataGuard instances • This instances will run indefinitely (no restrictions) • Should be activated • Silent bundle is also possible, requires signing VAR agreement For conference attendees – EUR 900 (reg EUR 1200 - 25%)
- 37. Next presentation from IBSurgeon • How to migrate 75Gb Firebird 1.5 to 2.5? • 5000+ stored procedures, 500+ tables, 400 users and 24x7 workmode •Mission Impossible, Part 5 (Starring Firebird!)