HPE Shadowbase Solution: Asymmetric Capacity Expansions
Internet travel companies send transaction requests to book to the master-booking node in Figure 1. The master-booking node is hosted on an HPE NonStop server, which is connected to any number of scalable NonStop and Windows query nodes via HPE Shadowbase data replication. This read-only function is offloaded from the master-booking node, since travel agents and Internet travel companies use the query nodes to look-up vacancy/seat availability information, etc.
- The outsource provider’s application is configured (no application modification was required) to perform all queries against the query nodes, yet still apply the booking transactions to the master booking node.
- At least one NonStop query node is architected to also act as a disaster recovery standby system for the booking application if that system fails.
- Additional query node replicates can be added as the query volume increases.
- The key structure on the master-booking node remains optimized for OLTP access (“skinny” keys), and the key structure on the query node is optimized for query (“fat” keys).
- Data from the master-booking node is also replicated to Windows servers running SQL, which supports a large Operational Data Store (ODS) application.
- Each of the NonStop read-only query nodes acts as a disaster recovery backup for the NonStop master node.
- The entire database resides on each of the read-only nodes, in essence allowing the provider to scale the application across multiple systems to handle unpredictable query volumes.
The above was adapted from the book: Breaking the Availability Barrier, Volume III: Active/Active Systems in Practice by Paul J. Holenstein, Dr. Bruce Holenstein, and Dr. Bill Highleyman.