How Do I Set Up Data Center in Cold Stand By Mode With Backup of Assets Data Only?

About this task

This use case explains how to backup, restore assets data during failover, failback operations, and how to subsequently merge analytics data in both the data centers during failback operation.

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 REST API periodically to take a snapshot of assets data from DC1 and store the snapshots in a suitable externalized storage system based on the RPO.
```
curl -si -X POST -H "content-type:application/json" -d '{"indices": "gateway_tenant_assets"}' http://es-host:es-port/_snapshot/repo-name/backup_file_name
```
This command takes a backup of asset data only. For more information about back up and restore, see Data Backup.

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:
```
curl -si -X POST -H "content-type:application/json" -d '{"indices": "gateway_tenant_assets"}' http://es-host:es-port/_snapshot/repo-name/backup_file_name/_restore
```
- Start webMethods API Gateway in DC 2.
- Reconfigure the load balancer by exposing DC 2 to the client.
During the failback process, perform the restore (overwrite) operation in two parts. Firstly, restore the assets data, and dashboard data from DC2 to DC1. Secondly, merge the analytics data, and logging data from DC2 to DC1.
- Run the following command to restore the assets data, and dashboard data from DC2 to DC1:
```
curl -si -X POST -H "content-type:application/json" -d '{"indices": "gateway_tenant_assets"}' http://es-host:es-port/_snapshot/repo-name/backup_file_name/_restore
```
- Run the following command to restore other indices such as analytics data, logging data from DC2 to DC1 to ensure that the data is merged between both the data centers:
```
curl -si -X POST -H "content-type:application/json" -d '{"indices": "gateway_tenant_*"}' http://es-host:es-port/_snapshot/repo-name/backup_file_name/_restore
```
- Start webMethods API Gateway in DC 1.
- Reconfigure the load balancer by exposing DC 1 to the client.