How Do I Set Up Data Center in Cold Standby Mode?

About this task

This use case explains how to set up data centers in cold standby mode for achieving disaster recovery.

For example, assume that you have two data centers DC 1 and DC 2 in the following landscape:

Data Center Name	Host Name	Region
DC 1	uk.myhost.com	United Kingdom
DC 2	us.myhost.com	United States

Here, the DC 1 is in active mode and DC 2 is passive. You want to bring up DC 2, when DC 1 goes down. Assume that DC 2 is in cold standby mode, then there would be no data in DC 2.

Pre-requisites

Install API Gateway in DC2 and ensure that the fix upgrades of DC1 is applied to DC2 too.
Run the following backup script periodically to take a snapshot of data from DC1 and store the snapshots in a suitable externalized storage system based on the RPO.
```
apigatewayUtil.sh create backup -name backup_file_name
```
For more information about back up and restore, see Data Backup.
Note: This command takes a complete backup. This impacts your RTO. To take a backup of the assets data alone, see How Do I Set Up Data Center in Cold Stand By Mode With Backup of Assets Data Only?.

Failover and Failback process

Procedure

During the failover process:
- Start API Data Store in DC2.
- Run the following command in DC 2 to restore the backed up data in API Data Store:
```
apigatewayUtil.sh restore backup -name backup_file_name
```
- Start API Gateway in DC 2.
- Reconfigure the load balancer by exposing DC 2 to the client.
During the failback process:
- Run the following command in DC 2 to back up the data:
```
apigatewayUtil.sh create backup -name backup_file_name
```
- Run the following command in DC 1 to restore the backed up data:
```
apigatewayUtil.sh restore backup -name backup_file_name
```
- Start API Gateway in DC 1.
- Reconfigure the load balancer by exposing DC 1 to the client.
To optimize your RTO, perform the following:
- Configure an external API Data Store to store the Trasactional Events (TE) and logs. For more information, see Connecting to an External Elasticsearch.
- Instead of taking a complete backup, take a backup of the assets data alone from the primary data center (DC1) and restore it in the secondary data center (DC2), which will in turn reduce your RTO. To take a backup of assets data, see How Do I Set Up Data Center in Cold Stand By Mode With Backup of Assets Data Only?.