You most probably dont need an RMAN catalog database

You most probably don't need
an RMAN catalog database
Introduction to the whitepaper
Yury Velikanov & Community
Sunday, Sep 22, 2:15 PM - 3:15 PM
Moscone West - 3014
Session ID# UGF9741
#OOW13 @yvelik

About Yury
Google: Yury Oracle [phone|email]
Twitter, LinkedIn, Blog, Slideshare, YouTube
Oracle ACE Director
Oracle Certified Master(9i/10g/11g + 15 OCP certificates)
Oracle DBA 15+ years(42+ months working for Pythian)
10 Problems with your RMAN backup script (author)
12 000+ views on SlideShare.net

About Yury
Google: Yury Oracle
10 Problems with your RMAN backup script (author)
12 000+ views on SlideShare.net

About Pythian
• Recognized Leader:
– Global industry-leader in remote database administration services and consulting for Oracle, Oracle
Applications, MySQL and Microsoft SQL Server
– Work with over 250 multinational companies such as Forbes.com, Fox Sports, Nordion and Western
Union to help manage their complex IT deployments
• Expertise:
– Pythian’s data experts are the elite in their field. We have the highest concentration of Oracle ACEs on
staff – 10 including 3 ACE Directors – and 2 Microsoft MVPs.
– Pythian holds 7 Specializations under Oracle Platinum Partner program, including Oracle Exadata,
Oracle GoldenGate & Oracle RAC
• Global Reach & Scalability:
– Around the clock global remote support for DBA and consulting, systems administration, special
projects or emergency response

Agenda
• Introduction
• Why RMAN catalog is an overhead? / COST
• Cases when catalog database is a MUST
• Benefits of using RMAN catalog / VALUE
• Catalog use-cases
– Catalog & MML integration
– Catalog & DR
– Catalog & FS
• Practical hints for catalog usage

DB Catalog
doesn’t provide more
HISTORY!

Introduction – Why?
• Many DBAs use RMAN catalog because
– It was a default option in 8.0
– It is recommended by Oracle
– It was created before them
• Many DBAs don’t
– Use most of the catalog benefits
– know how to assess cost involved
– know how to justify catalog existence
@dbareactions

RMAN catalog is an overhead COST
• IMPLEMENTATION COST
• MAITENANCE & RUNNING COSTS
• DEPENDENCIES
• DOWNTIME
• AVAILABILITY
• TUNING
• BACKUP
• COST per database
- More databases - less cost
- Cost vs Risk

RMAN catalog database is a MUST
• Disaster Recovery
– Data Guard (standby database)
– Backups from both DR sides
– Shared backups media

• Control File size is way to big
– control_file_record_keep_time
– Manage retention (if applicable)
– Restore alternative MML handle

• KEEP
– Keep a backup for longer than current retention policy allows
– Long term backups need a special care and should be treated
as archiving
• MML retention should be adjusted as necessary
• Other tape pool / file system than regular backups
• oracle database software & operational system
– There are alternative ways (file system)
• RESTORE PREVIEW + OS copy
• BACKUP + UNCATALOG

RMAN catalog Benefits / VALUE
• Additional bird level view - control level
– Many databases
– Small DBA team
– Scheduling issues
– Manager’s view

• Volumes & Throughput monitoring
– Day to day monitoring
– Report deviations (archived logs)
– Troubleshooting data
– Tuning (compression, IO vs CPU vs TIME)
– Chargeback

Capacity planning / VALUE
• Challenge (centralized NFS)
– Used for many databases backups
– Retention policy varies
– Incremental backups + Weekly cycles
– RAC multiple backups from different nodes
• Solution – Catalog DB
– Centralized data for all databases
– Regular data snaps
– Custom data analysis tables

• MML & Catalog DB
– Tends to have longer retention policy
• Often retention policy isn’t managed by RMAN
– Simplifies and unifies controlfile recovery
• There are alternatives, e.g. MML handle from log files

• RMAN scripts
Pros
– Standard way to backup
– Centralized control / easer change
Cons
– Dependency from RMAN catalog
– Limited syntax
• About Stored Scripts: Any command that is
legal within a RUN command is permitted
in the stored script.
!shell rules!

VALUE
• Additional high-level view of backups
• Volumes & Throughput monitoring
• Information for Capacity planning
• Simplifies controlfile recovery (MML)
• Repository for generic RMAN scripts
Catalog Doesn’t
• Keep longer history
• Replace control file backups

Catalog & MML integration
• Control File Auto recovery (challenge)
– How it works
• CONFIGURE CONTROLFILE AUTOBACKUP ON
• standard handle name (%F format)
c + {database ID} + {date} + {XX}
• XX - hexadecimal incremental from 00 to FF
– Restore
• Restore freshest controlfile
• RMAN Tries FF, FE, ….. 01, 00
– MML 1 round trip 2-5 minutes
• 240 roundtrips = 8-20 hours maxseq and maxdays

Catalog & MML integration
• Alternative control file restore options
– MML REPOSITORY
– RMAN LOG
– HANDLE name
• RMAN: “ENV=” or “format”
• Catalog addresses
– Difficulties in MML & DBA communications
– Absence of MML access
– Standard way to restore (easier)

Catalog, MML & RETENTION
RMAN rarely used for retention management
– Typically there are many MML clients
• File systems
• MS Exchange / Lotus Domino
• Other databases
– There are pools to send backups to
• Weekly
• Monthly
• Custom
There is a synchronization challenge

Catalog & Disaster Recovery
• Disk based backups are local
– Accessible from one site only
• Tape based backups are global
– Accessible from both sites
• Review the SITE_KEY column in RMAN catalog views
• KEY: CATALOG disk based backups on other site
“Backup and Recovery Reference 11g R2”
– “RMAN Backups in a Data Guard Environment”

Catalog & File System => MML
• Simple unless ….
• Relies on file system to tape backups
– Strong recommendation to use MML integration
• Missing backups
• Too many copies for SOME backup sets
– If you use
• Don’t use DELETE OBSOLETE
• RESTORE … PREVIEW
• Manual synchronization

PRACTICAL HINTS THE CATALOG USAGE

Practical hints for catalog usage
• DBID must be different for all databases
• Do not separate Development & Production
• To use or not to use RMAN catalog stored scripts?
• Use resync catalog
• RMAN setup for catalog DB failures
• Introduce two catalog DBs to ensure HA

Catalog makes it simple
• RMAN Catalog is an overhead
• You may manage without it
• However an RMAN Catalog
– simplifies backup management
– adds additional benefits
– reduces risks
– there are other special cases
• Cost is opposite proportion to DB count
• Consider leveraging other catalog DB benefits

If you don’t use catalog DB
• Make sure that
– control_file_record_keep_time is greater than
maximum retention period you may use
– You have an easy access to archive of RMAN LOG
files
– You have knowledge & access to MML server
• at least you have a best friend in tapes
management team
• Assess catalog DB benefits on regular basis

Google: Oracle Yury
Blog, Twitter, Linkedin, ACE … email, phone number
Whitepaper!
Session ID# UGF9741
#OOW13 @yvelik

THANK YOU
Google: Oracle Yury
Whitepaper!

You most probably dont need an RMAN catalog database

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