Tuesday, 16 June 2015

Backup Guidelines

Causes of Unplanned Down Time

Software Failures
o Operating system
o Database
o Middleware
o Application
o Network

Hardware Failures
o CPU
o Memory
o Power supply
o Bus
o Disk
o Tape
o Controllers
o Network
o Power

Human Errors
o Operator error
o User error
o DBA
o System admin.
o Sabotage
„h Disasters
o Fire
o Flood
o Earthquake
o Power failure
o Bombing

Causes of Planned Down Time

Routine Operations
o Backups
o Performance mgmt
o Security mgmt
o Batches
Periodic Maintenance
o Storage maintenance
o Initialization parameters
o Software patches
o Schema management
o Operating system
o Middleware
o Network
 New deployments
o HW upgrade
o OS upgrades
o DB upgrades
o MidW upgrades
o App upgrades
o Net upgrades


Minimizing Unplanned Downtime Guidelines
 Use RAID data storage with mirroring ( 1+0 is a good choice).
 Maintain offsite storage of your backups with a reliable vendor. Make is part of your
recovery testing program.
 Normally, for a production database, operating in Archivelog mode is a must.
 Multiplex the control files on separate disk drives managed by different disk controllers.
 Oracle strongly recommends that you multiplex the redo log file.
 After every major structural change, back up the control file. You can take backup of the
control file every hour.
 If you backup to a tape, backup to two copies. The media might be defective.
 Make auxiliary files part of your backup: (SPFILE) or the init.ora, sqlnet.ora,
tnsnames.ora, password and wallet files.
 Log your backup operations.
 Make every application has its own tablespace.
 Use Data Pump utility for supplemental protection.
 Make a plan to make sure that the backups are actually readable and valid.
Make database recovery testing plan.
Always keep a redundancy set online (use flash recovery area for this purpose) so you can recover faster. A redundancy set has:

  •  Last backup of all datafiles
  •  Last backup of the control file
  •  Multiplexed copies of the current redo log files
  •  Copies of the current control file
  •  The archived redo logs since the last backup
  •  Auxilary files: SPFILE or the init.ora, listener.ora, and tnsnames.ora, pwsd