Adding an HDR server to a cluster

About this task

Let's add an HDR secondary node to our cluster

Procedure

Prepare the SQLHOSTS files

Update the SQLHOSTS file at primary. and at both SDS and HDR secondary servers:

g_mach11  group     -         -          i=10
 myprim    ontlitcp  primhost  prim_port  g=g_mach11
 hdr       ontlitcp  hdrhost   hdr_port   g=g_mach11 
 sds1      ontlitcp  sds1host  sds1_port  g=g_mach11

Configure the ONCONFIG files

In order for HDR to work, certain ONCONFIG parameters must be exactly the same on both the primary and secondary. In many cases, this means they cannot be changed while either server is running. These parameters include DRAUTO, DRINTERVAL, DRTIMEOUT, settings related to the root dbspace, settings related to logical logs, and more. To ensure these settings match, one technique is to copy the onconfig of the primary to the secondary, and then modify the few things that must be different, such as DBSERVERNAME. You should plan for these settings before bringing the primary up. This example just uses the defaults.
Backup the primary
On the primary, take a level zero backup:
```
ontape -s -L 0
```
Register the HDR secondary server with the primary
On the primary, run:
```
onmode -d primary hdr
```
Prepare the HDR secondary server's disk

The storage used on the HDR secondary must match that of the primary (for example, number of dbspaces, number of chunks, chunk sizes, pathnames, and offsets). Since this example uses the backup to restore the HDR secondary server, it is only necessary that the chunk files exist and have the proper permissions.

Restore the backup on the HDR secondary server

On the HDR server, perform a physical restore of the level 0 backup:

ontape -p
  Three questions will be asked.  Answer as shown below:
   Continue restore? (y/n) y
   Do you want to back up the logs? (y/n) n
   Restore a level 1 archive (y/n) n

Bring the HDR secondary server into online mode
After the restore is complete, the HDR secondary will be in recovery mode. Run the following command:
```
onmode -d secondary myprim
```
HDR secondary is up and running! Run onstat -g driat the primary and HDR secondary to check HDR status. Our cluster now looks like this:
Figure 1: The cluster: Primary and one SD secondary