r4 - 2014-01-14 - 15:36:51 - RalphSchoonYou are here: TWiki >  Deployment Web > DeploymentInstallingUpgradingAndMigrating > BackupCLM > ReplacingOfflineBackupsWithOnlineBackups

uc.png Replacing offline backups with online backups

Authors: HariVetsa
Build basis: CLM

This article is intended to replace existing offline backup process with online backup of database during maintenance activities.

Currently, Rational Engineering Services (RES) takes backups of all the databases, work item indices and full text indices before every scheduled upgrade of the CLM Server. The above backups are being taken after the application was shut down but before the upgrade process starts.

Unfortunately, this process is causing longer application unavailability than necessary. Both RES and CLM Development are in constant search for opportunities to reduce the downtime required to upgrade CLM software. This initiative promoted us to reevaluate our process.

The primary objective for the offline backups before an upgrade process is to guarantee the application state of recovery in case we have to backout the change. This is traditional recommendation from every software and hardware vendor. Our hunt was to ensure the objectives are not compromised, but break out the traditional thought process that doesn't work for us any longer.

What happens if we use online backups instead of offline backups for backout plan? We already use the online backups and rollforward recovery for Business Continuity Process (BCP). Why canít we use the same online backups for application recovery before any software upgrade?

The only difference we have observed is, the BCP Process minimizes the data loss (we want to recovery to the latest point possible) whereas the backout process needs to recover the application to an exact point before the software upgrade. The recovery information is already there in the Archive logs.

After little bit more analysis, the following process can be used to replace offline backups with online backups:

  1. 2-3 hours before the application upgrade, take an online backup of all the databases
  2. Make sure all the online backups are completed successfully
  3. Stop the CLM applications for upgrade
  4. Note the timestamp after all the applications are stopped and disconnected from the databases. (This timestamp will be used for recovery.)
  5. Take a backup of work item indices and full text indices
  6. Make sure you have all the archive log files of the databases to rollforward
  7. Perform application upgrade

The following diagram depicts the change in backup processes using offline backups and online backups.

offlineonlinebackupprocess.png

In case you need to execute a backout plan, there is only one difference between the backout plan between offline and online backups. Instead of just restoring your backup, you will restore the backup and rollforward the transactions. Since the online backups are taken just few hours before the upgrade, the recovery of these transactions will be quick.

We upgrade the CLM server behind jazz.net, which is being used by RTC development team, once every milestone (or sprint). On average this server gets upgraded 15-20 times in a calendar year. We had to execute a backout procedure one in the last 2 years. Given the low probability of needing to resort to a backout plan, it makes sense to move to an online backup process before starting application upgrades.

Please ensure the process works for you in our staging or test environments before adopting into production.

Here are some commands that can be used as reference:

  1. How to determine last successful backup for IBM DB2?
    SELECT MAX(start_time) FROM SYSIBMADM.DB_HISTORY WHERE operation = 'B' AND operationtype = 'N' AND sqlcode IS NULL
  2. How can I obtain details of archive logs produced since last backup for IBM DB2?
    SELECT start_time, end_time, location, entry_status, sqlcode, sqlstate FROM SYSIBMADM.DB_HISTORY WHERE operation = 'X' AND operationtype = '1' AND start_time > (SELECT MAX(start_time) FROM SYSIBMADM.DB_HISTORY WHERE operation = 'B' AND operationtype = 'N' AND sqlcode IS NULL)

Related topics:

External links:

Additional contributors: None

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