Service Continuity

Automatic Service Restarting

SAP HANA provides the reliability mechanism. Its Daemon process monitors other SAP HANA processes, including the NameServer, IndexServer, Preprocessor, Complieserver, Statisticsserver, and Xsengine processes. When an SAP HANA process becomes faulty, the system automatically restarts the process.

HA

In single-node deployment:

• When the physical server where an SAP HANA node is deployed becomes faulty, the system automatically creates an SAP HANA node on another physical server, attaches the log and data volumes to the new node, and switches services from the faulty node to the new node to ensure service continuity.
• In HA mode, the active and standby nodes synchronize data using System Replication. When the active SAP HANA node becomes faulty, you can manually switch services to the standby node.

In cluster deployment:

SAP HANA provides host auto failover (HAF). When a worker node in the cluster becomes faulty, the system automatically switches services from the faulty node to the standby node for cluster HA.

Backup

The following backup modes are supported:

• Based on shared files

  This backup mode adapts to the SAP HANA backup mechanism. Two SAP HANA nodes (NFS servers) constitute an HA NAS system. SAP HANA data is backed up to the backup volume. Then, the data can be backed up to OBS buckets.

• Based on volumes
  This backup mode is provided based on volume backup on the public cloud platform. In this mode, you must back up and restore data by yourself and ensure data consistency in SAP HANA data and log volumes.

  • Data can only be backed up within an AZ. To do so, create a snapshot for volumes. Then, the snapshot can be used for rolling back data or creating new volumes. The newly created volumes are within the AZ where the original volumes locate.
  • Data can be backed up in OBS buckets. To do so, create a snapshot for volumes and back up data based on the snapshot. Then, data can be restored both within and across the AZ.