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Okay, so here we go …. setting up an hadr environment….  HADR in it’s lowest form is very straight forward to set up.  Here are the steps to start HADR

1. You need to have either a second machine with DB2 installed, or alternately you can use a second instance.  I’m sure I don’t have to tell you that using a second instance of DB2 on the same machine defeats the whole purpose of this, but it is fine for testing
2. Make sure you have Log Retain set on either explicitly or implicitly
3. Make sure you have db cfg LOGINDEXBUILD set to On
   you need to set the following db config parameters –
   HADR_LOCAL_HOST set to the IP address or host name of the local host
   HADR_LOCAL_SVC set to the port you are going to assign
   HADR_REMOTE_HOST set to the IP address of standby instance – same as LOCAL if using an alternate instance
   HADR_REMOTE_SVC set to the standby port should be at least LOCAL +2
   HADR_REMOTE_INST set to standby instance name
4. Make a backup of your database – can be either online or offline
5. Send the backup to the standby machine.  If you are using two instances, then you can skip this
6. restore from the backup on the standby instance  — I’m assuming you are using the IBM SAMPLE database for this excerise.
7. On the standby database, you need to set the same db config values except you need to flip them around so they are correct – LOCAL values become REMOTE values.
8. On the standby machine/instance “db2 start hadr on database sample as standby”
9. On the primary machine/instance “db2 start hadr on database sample as primary”
10. Check if HADR is working – Do “db2 get snapshot for database on sample” — in the output look for:
    HADR Status
      Role                   = Primary
      State                  = Peer
      Synchronization mode   = Nearsync
      Connection status      = Connected , 11/26/2009 17:47:40.447523
      Heartbeats missed      = 0
      Local host             = 192.168.0.105
      Local service          = 10000
      Remote host            = 192.168.0.101
      Remote service         = 11000
      Remote instance        = DB2
      timeout(seconds)       = 120
      Primary log position(file, page, LSN) = S0000036.LOG, 0, 000000000B3B0000
      Standby log position(file, page, LSN) = S0000036.LOG, 0, 000000000B3B0000
      Log gap running average(bytes) = 0

    if it says anything other than ‘peer’ then there is a problem. One common problem is a firewall… if you are doing this on a windows box with a firewall, then you will have to open up the HADR ports both ways.

You now have a HADR pair up and running — anything you do on the primary will be done on the standby as well.  Be sure to review things that don’t work. 

Standby for Part 3 where we will go over how to switch back and forth from primary to standby.