Configuring DB2 HADR with Zero downtime

A few weeks ago I setup DB2 HADR for a large bank and they wanted the setup to be in the minimal downtime.Traditionally, I have been implementing this using offline backups. Using offline backups will make the system offline for a certain period that vary based on you database size. The new challenge was to make it with the minimal or no downtime. I thought online backup would require certain workarounds or tweaks and might not work. However, it worked like a charm and very straightforward.

Here are the steps I followed to make the implementation in zero down time:

1. Take full online backup from the primary DB.
2. Restore the backup on the standby server.
3. Change HADR configuration parameters for the standby machine.
4. [OPTIONAL -for 9.7.1 or higher] enable read on standby on the standby machine.
5. Configure HADR parameters on the primary database.
6. Start HADR on the standby machine as standby.
7. Start HADR on the primary database as primary.

You need not to do any roll-forward commands on the standby database. HADR will take case of transferring all the delta logs from the primary to the standby.

A common pitfall would be the HADR ports are not open or blocked by the firewall. So, please make sure you communicate these ports to your network administrator.