CERN IT Department

CH-1211 Geneva 23

Switzerlandwww.cern.ch/

it

Emil Pilecki, IT-DB

Standby configurationclean up and standardization

CERN IT Department

CH-1211 Geneva 23

Switzerlandwww.cern.ch/

it

Standby configuration cleanup

• On both primary and stanbdby ensure that• DB_UNIQUE_NAME is set

• LOG_ARCHIVE_CONFIG=DG_CONFIG is set and lists all unique names in the configuration• useful for multi-standby configurations, especially in

synch mode and with broker

• Always specify DB_UNIQUE_NAME for each remote LOG_ARCHIVE_DEST_n destination

• LGWR option is removed from LOG_ARCHIVE_DEST_n• obsolete in 11.2

CERN IT Department

CH-1211 Geneva 23

Switzerlandwww.cern.ch/

it

Standby configuration cleanup

• Symmetric configuration for faster switchover• Configure redo transport on standby for easier

switchover/failover• now often not configured

• Configuration that use downstream capture are at risk if standby opened in RW mode and starts shipping redo

• Use LOG_ARCHIVE_DEST_STATE_n=DEFER to safeguard from accidental redo shipment from standby

• set to ENABLE before switchover

• Use LOG_ARCHIVE_CONFIG=NORECEIVE/NOSEND as a 2nd safety measure for configurations with downstream

• to be tested if it works correctly

• remove this settings before switchover

CERN IT Department

CH-1211 Geneva 23

Switzerlandwww.cern.ch/

it

Standby configuration in LDAP

• <SC_DB_UNIQUE_NAME> - already in LDAP

• Link between primary and standbys entities defined in LDAP• to quickly see what standby databases are configured for

a given primary

• useful for monitoring tools, such as RACMON

<SC_STANDBYS> - optional sub-entity of DB entity as <SC_HOSTS>

<SC_STANDBY_ID=1> - first standby<SC_STANDBY_ENTITY> - first standby DB entity name

<SC_STANDBY_TYPE> - disaster recovery or active (exposed to users)

<SC_STANDBY_ID=2> - second standby<SC_STANDBY_ENTITY> - second standby DB entity name

<SC_STANDBY_TYPE> - disaster recovery or active (exposed to users)

CERN IT Department

CH-1211 Geneva 23

Switzerlandwww.cern.ch/

it

Standby naming conventions

• Standardize naming for standby databases• Unify! Use the same naming scheme for

• LDAP entities

• DB_UNIQUE_NAME parameter

• Local TNS aliases

• Proposal• dbname – primary database

• dbname_dg_racX – standby for disaster recovery

• dbname_adg_racX – active standby exposed to end users

CERN IT Department

CH-1211 Geneva 23

Switzerlandwww.cern.ch/

it

Standby naming conventions

• Replace names in LDAP and DB_UNIQUE_NAME

• dbname_standby_racX => dbname_dg_racX

• Remove excess local TNS aliases

• dbname_primary and dbname_standby

• dbname_standby_racX

• aliases pointing to specific instances on standby databases

• There should be only one local TNS alias per database in the configuration

• dbname – always pointing to the primary

• dbname_dg_racX – pointing to the specific DR standby

• dbname_adg_racX – pointing to the specific active standby (exposed to end users)

• Retain TNS aliases pointing to specific instances on primary

• useful for troubleshooting and data pump

CERN IT Department

CH-1211 Geneva 23

Switzerlandwww.cern.ch/

it

Standby for migration purposes

• Temporary standby DBs created for migration purposes are not covered by the rules describedin this presentation• Symmetric configuration is not needed

• DB_UNIQUE_NAME don’t have to be set

• LDAP standby information can be omitted

• Local TNS aliases should eventually be the same as on primary

CERN IT Department

CH-1211 Geneva 23

Switzerlandwww.cern.ch/

it

Conclusions

• Use the new naming convention and setup guidelines while configuring new standby databases

• Gradual clean up of existing databases to make them compliant with the new guidelines

• Deadline for non-PROD: October 2012

• Deadline for PROD: November 2012

• LDAP changes not yet implemented – will be announced separately when ready