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Using Oracle Data Guard for Applications Disaster Recovery … and More. Jeff Slavitz Independent Consultant Oracle Applications DBA and Developer Jeff@OracleAppsPro.Com. What Would You Do???. It’s Monday morning.

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using oracle data guard for applications disaster recovery and more

Using Oracle Data Guard for Applications Disaster Recovery … and More

Jeff Slavitz

Independent Consultant

Oracle Applications DBA and Developer

Jeff@OracleAppsPro.Com

what would you do
What Would You Do???
  • It’s Monday morning.
  • Fatal production system hardware problem, or production hardware location is now a smoking hole
  • Expect Production to be down for an unforseen amount of time
  • It is year-end, you have a new manager and your senior DBA is on vacation

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

slide3

What is your backup situation?

  • Do you have a cold backup? On-site or off-site?
  • Do you have a hot backup. On disk? On tape? On another accessible site? How recent is it?
  • Will you be able to read your tape backups?
  • How recent are the archive logs that are now on the system that is down?
  • Where are your archive log backups since the last hot backup?

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

options
Options
  • Restore and clone latest backup to a test box. How familiar is your DBA with RMAN recover? Is the box big enough to run the company? Will interfaces work (EDI, Payroll, …)
  • Rent or buy a box. How long would it take to find and setup a new box?
  • How long will it take to get the company up and running? Have you practiced this process or is this a fire drill? How many P1s will you need?
  • How much data will the company lose?
  • What does the company do while Oracle is down?

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

how do you feel
How Do You Feel?

How Does Your Manager Feel?

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

slide6
Or…
  • In 15 minutes you’ve fully switched Oracle Applications over to a standby database
  • You’ve tested the procedure with all DBAs
  • The failover procedure is fully supported and documented by Oracle
  • Interfaces are tested on the standby database
  • You run the entire company once a month for a short period of time on the standby database
  • You have a test standby database that DBAs practice on and you use for reporting purposes

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

how do you feel7
How Do You Feel?

How Does Your Manager Feel?

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

my goal today
My Goal Today
  • Tell you how you can be relaxed, not stressed, in a disaster recovery situation
  • What is Data Guard
  • Describe added value Data Guard and Flashback provide in addition to disaster recovery
  • On a high level, review steps to implement Data Guard and Flashback
  • Lessons learned - what Metalink notes don’t tell you
  • Please ask questions as I go along
  • Apologies to the non-DBAs

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

what is data guard
What is Data Guard?
  • Data Guard is part of Oracle, not a separate product, which provides a set of services that create, maintain, manage, and monitor one or more standby databases
  • Data Guard maintains these standby databases as transactionally consistent copies of the production database
  • Data Guard can switch any standby database to the production role

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

without data guard
Without Data Guard

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

with data guard
With Data Guard

Oracle® Database High Availability Best Practices 10g Release 2 (10.2)

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

why not use data guard
Why Not Use Data Guard?
  • Too expensive – not! You already have and license it if you have Oracle Enterprise Edition. Nothing to purchase in order to implement what we discuss today.
  • Too bleeding edge. Data Guard has been around since Oracle 9i and Oracle 8i as Standby Server.
  • Too difficult to implement. Well documented by Oracle and completely supported. This presentation is a roadmap through the process plus my own observations and experiences.
  • No DR box. Use test box for standby. Doesn’t protect against smoking hole but it’s better than nothing.
  • How often do you really need DR? Is once enough? Plus a standby database can be used for other purposes.

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

why you should use data guard
Why You Should Use Data Guard
  • If your Production Oracle Applications instance went away would anybody notice?
  • Our job is to protect the company’s data
  • Your manager will thank you – DR is important.
  • Data Guard plus Flashback provide added value:
    • Instant clone
    • Reporting instance
    • Many exciting possibilities!

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

what is flashback
What Is Flashback?
  • Introduced in Oracle 9i
  • Flashback is part of your Oracle database – no licensing requirement
  • Provides a rewind button for your data
  • Flashback Database - return database to a previous point in time
  • Flashback Table - return a table to a previous point in time
  • Flashback Query – see data at a previous point in time

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

data guard and flashback together
Data Guard and Flashback Together

Many possibilities when used together …

Scenario:

Show stopper problem in Production

Need to test a patch or data fix with current production data on test system ASAP

Old school: Clone

Time to complete: ??? Hours

Data Guard: Use standby database as an instant clone

Time to complete: 10 minutes

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

instant clone
Instant Clone
  • Activate standby database
  • Perform testing on standby database
  • When testing complete, flashback standby database to activation point in time
  • Test again? Allows destructive testing.
  • When all done, flashback and re-activate standby database

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

reporting database
Reporting Database

Scenario:

You want a data warehouse which is a snapshot of Production as of 9pm the day before. Users need access via Oracle Applications and Discoverer

Old School: Daily clone

Data Guard: Use standby database as a reporting database

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

reporting database18
Reporting Database
  • Activate standby database
  • Users login to standby database with Oracle Applications, Discoverer, or any other tool. Users can make changes in Application though they won’t be saved after Flashback.
  • Archive logs accumulate on standby database
  • At 9pm each day flashback database to the way it was at 9pm the day before, apply archive logs created since then, reopen database
  • Can have multiple standby databases – one for DR, one for reporting, one for ???
  • Oracle 11i Active Data Guard allows read-only access to standby database while it is being updated from primary

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

bumps along the way
Bumps Along the Way
  • Time implementation so it’s not at year-end
  • Bumpy transition into production – low Test database activity is not an accurate picture of how Data Guard and Flashback will work in Production
  • 3mb network was not enough for standby to keep up with primary - needed 10mb just for Data Guard
  • Do periodic full company test of standby system
  • Data Guard and Flashback implementation are well documented but there is a learning curve

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

implementing data guard and flashback
Implementing Data Guard and Flashback

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

hardware configuration
Hardware Configuration

Primary

(California)

Standby

(Nevada)

Database

Database

45mb of which

8-10mb used by

Data Guard

Application

Application

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

software configuration
Software Configuration
  • Database
    • 10.2.0.4
    • Data Guard Physical Bundle patch 7936993
    • Data Guard Logical Bundle patch 7937113
    • Data Guard Broker Bundle patch 7936793
  • Applications 11.5.10.2

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

data guard setup
Data Guard Setup

Two Metalink notes:

    • Note 216212.1: Business Continuity for Oracle Applications Release 11i, Database Releases 9i and 10g
    • Note 452056.1: Business Continuity for Oracle Applications Release 12 on Database Release 10gR2 (earned my vote for best Metalink note ever)
  • Use Release 12 note
  • Better configuration, simpler and works fine with 11i
  • Substitute APPL_TOP for Instance Top in text

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

logical vs physical
Logical vs Physical

Two types of standby databases

  • Physical
    • Byte-for-byte duplicate of the primary database
    • Archived redo logs transferred from primary database are directly applied to the standby database
    • When standby in recovery mode it is mounted not open
  • Logical
    • Different structure than the primary database
    • Oracle uses SQL statements to update standby
    • Standby can be open while it is being updated

Today we are talking about Physical standby databases

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

maximum protection mode
Maximum Protection Mode
  • Three types of protection – Maximum Protection is highest level of data security
  • Primary database changes are not committed until it has been confirmed that the data is available on at least one standby database
  • If Oracle determines that the redo data cannot be transferred from the primary server to the standby server, it will automatically stop the primary database instance
  • Data transmitted synchronously - network implications

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

maximum performance mode
Maximum Performance Mode
  • Default protection mode
  • The commit operation on the primary database is not contingent upon the data being received by the standby server
  • If all of the standby servers become unavailable, processing will continue on the primary database
  • Data transmitted asynchronously
  • This performance mode is what are discussing today

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

maximum availability mode
Maximum Availability Mode
  • Second highest level of data security
  • Primary database changes are not committed until it has been confirmed that the data is available on at least one standby database
  • If the standby database becomes unavailable for any reason, the protection mode is temporarily lowered to maximum performance until the problem has been corrected

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

data guard installation overview
Data Guard Installation Overview
  • Develop a naming convention for your primary and standby database servers e.g. PROD_<primary server>, PROD_<standby server>
  • Create standby redo logs: one more than number of redo logs, same size as redo logs, do not multiplex
  • Clone database to standby
  • Copy datafiles to standby with closed database or with open database using RMAN (see note 753241.1, Configuring Standby Database on R12 using RMAN Hot Backup)
  • Test primary and standby and listeners using tnsping
  • Clone application to standby
  • You are now ready to turn on Data Guard

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

primary init ora ifile parameters
Primary init.ora ifile Parameters

# Global unique name

db_unique_name=PROD_CAMELDB1

# Flash recovery area. This is the default location for control files, online

# redo logs, archived redo logs, flashback logs, RMAN backups.

db_recovery_file_dest=/u01/oracle/flash_recovery_area

# First destination for archived redo logs

log_archive_dest_1 =

'LOCATION=USE_DB_RECOVERY_FILE_DEST MANDATORY‘

# Second destination for archived redo logs

log_archive_dest_2 = 'SERVICE=PROD_LNXDRDB1

valid_for=(online_logfiles,primary_role)

db_unique_name=PROD_LNXDRDB1 LGWR ASYNC=20480

OPTIONAL REOPEN=15 NET_TIMEOUT=30‘

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

primary init ora ifile parameters30
Primary init.ora ifile Parameters

# Limit on the total space available to the flash recovery area.

db_recovery_file_dest_size=100g

# In minutes, how long you want to keep flashback files. Since using

# guaranteed flashback really don't need this to be too big.

db_flashback_retention_target=120

# On/Off switch for sending logs to standby system

log_archive_dest_state_2 = defer

# Databases in Data Guard configuration using my instance naming convention

log_archive_config='dg_config=(PROD_CAMELDB1,PROD_LNXDRDB1)‘

# Log gap detection and resolution when this database is the standby

fal_server = 'PROD_LNXDRDB1‘

fal_client = 'PROD_CAMELDB1'

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

start data guard
Start Data Guard

Start primary and second database and listeners

  • Primary: startup
  • Standby: startup mount

Turn on archive redo log transport on primary

  • alter system set log_archive_dest_state_2=enable;

Put standby in recovery mode

  • Recover managed standby database using current logfile disconnect;

Confirm logs are shipping to standby

  • Primary: alter system archive log current;
  • Standby: Check archive directory or query v$archive_log

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

care and feeding of data guard
Care and Feeding of Data Guard
  • Check alert log of primary and standby on a regular basis
  • Set Enterprise Manager to email you when an error shows up in alert log
  • Automatic archive log gap resolution usually works but network connectivity issue can require you to manually fix
  • Primary alert log will notify you when a gap exists:

FAL[client]: Failed to request gap sequence

GAP - thread 1 sequence 435-442

  • Copy missing archive logs from primary to standby
  • On standby: alter database register logfile …

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

flashback
Flashback
  • db_recovery_file_dest
    • defines Flash recovery area disk location
    • This is the default location for control files, online redo logs, archived redo logs, flashback logs, RMAN backups
    • Archive logs are placed in flashback area in sub-directory with date
    • DO NOT delete files in flashback area manually; database calculates space available based on what RMAN has done
  • db_recovery_file_dest_size
    • Specifies limit on the total space to be used by the flash recovery area
    • Check space usage using v$flash_recovery_area_usage
    • When recovery area is full database stops!
  • db_flashback_retention_target
    • Defines in minutes, how long you want to keep flashback files
    • Since using guaranteed flashback don't need this to be too big
  • To turn flashback on: mount database and alter database flashback on

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

switchover database steps
Switchover – Database Steps
  • Seamless switch from primary to standby
  • Switch existing primary to new standby:
    • Shutdown application
    • Confirm all logs received and applied on standby
    • alter database commit to switchover to standby with session shutdown;
    • Recover managed standby database using current logfile disconnect
  • Switch existing standby to new primary:
    • alter database commit to switchover to primary;
    • alter database open;
    • alter system set log_archive_dest_state_2=enable;
  • Confirm logs are shipping to standby by checking alert log, archive directory or query v$archive_log

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

switchover application steps
Switchover – Application Steps
  • Some of these steps are not in Metalink note but are required
  • Clear application context: exec fnd_conc_clone.setup_clean
  • Run adautocfg on database and application tiers
  • Run cmclean.sql (note 134007.1) to avoid Output Post Processing manager not starting
  • Update fnd_concurrent_requests
    • Change logfile_name and outfile_name to new APPLCSF path
    • Change logfile_node_name and outfile_node_name to new host name
  • Update fnd_conc_req_outputs (for XML reports)
    • Change file_name to new APPLCSF patch
    • Change file_node_name to new host name

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

switchover application steps36
Switchover – Application Steps
  • Update wf_notification_attributes.text_value with new node name
  • Update wf_item_attribute_values.text value with new node name
  • Check for any other profile values that contain old node name
  • Clear Apache cache
  • Start application and send users new login url
  • Synchronize APPLCSF log and out files
  • Use rsync
    • Faster than scp and only copies changed files

rsync -avz

$APPLCSF/out/${TWO_TASK}*/ - applprod@lnxdrapp1:$APPLCSF/out/${TWO_TASK}*

  • Consider setting cron job to synchornize APPLCSF in case of system failure

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

failover
Failover
  • Immediate switch of primary to standby system
  • Some archive log data may be lost due to network latency
  • On standby-soon-to-be-primary:
    • Cancel database recovery
    • alter database commit to switchover to primary
  • Configure application as shown in Switchover
  • Even with cron job synchronizing APPLCSF log and out files you probably won’t get all report output
  • Repair former primary system

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

failover sync old primary as new standby
Failover – Sync Old Primary as New Standby
  • Establish new standby by copying primary datafiles using RMAN, cold backup or flashback. To use flashback:
    • Find the SCN when the existing primary database became the primary:

select to_char(standby_became_primary_scn) from v$database;

  • On new standby:
      • Startup mount
      • flashback database to scn <above #>
      • alter database convert to physical standby;
      • recover managed standby database using current logfile disconnect;

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

instant clone or reporting database
Instant Clone or Reporting Database
  • On standby:

Cancel standby recovery

create restore point STBY_ON guarantee flashback database

Active and open database

Configure application as in Switchover

  • Users can now login to the standby database through Oracle Applications, Discoverer or anything.
  • Apply patches, test, update data in standby database.
  • To revert to restore point STBY_ON and do further testing as needed:

Shutdown immediate

Startup mount

Flashback database to guaranteed restore point STBY_ON

Alter database open

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

resume standby operation
Resume Standby Operation

On Standby:

  • Shutdown application
  • Shutdown database
  • Startup mount
  • Flashback database to restore point STBY_ON
  • Alter database convert to physical standby

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

lessons learned
Lessons Learned
  • Script as much as possible – you will make typos under time pressure
  • Use Enterprise Manager to see how Data Guard affects your system and tune accordingly
  • Implement Data Guard and flashback at different times
  • Setup one test database using Data Guard for testing and training

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

for the future
For the Future
  • Try Maximum Availability protection
  • Use Enterprise Manager to manage Data Guard. This requires Data Guard Broker implementation which requires use of spfile.
  • Completely script switchover and failover as shown in note 452056.1
  • Use RMAN to backup standby database only
  • Upgrade database to 11G and experiment with Active Data Guard. This allows you to create a read-only database that is open and is constantly updated from primary.

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

for more information
For More Information
  • Google (it knows everything)
  • http://blogs.oracle.com/stevenchan
  • Note 452056.1 – Business Continuity for Oracle Apps Release 12 on Database 10GR2 (works fine for 11i)
  • Note 216212.1 – Business Continuity for Oracle Apps Release 11i, Database Releases 9i and 10G
  • Note 753241.1 – Configuring Standby Database on R12 using RMAN Hot Backup (works fine for 11i)
  • Note 805438.1 – How to Open Physical Standby For Read Write Testing and Flashback
  • Data Guard Redo Transport & Network Best Practices Oracle 10GR2 White Paper
  • Oracle Data Guard Concepts and Administration manual
  • High Availability Best Practices manual
  • Backup and Recovery Reference manual

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

slide44

Questions?

Want the latest version of this presentation?

www.OracleAppsPro.com

Jeff Slavitz

Jeff@OracleAppsPro.com

(415) 388 - 3003

Jeff Slavitz - NorCal OAUG Training Day 2010 v3

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