IBM® IMS® Recovery Expert for z/OS® is a storage-aware backup and recovery solution that integrates storage processor fast-replication facilities with IMS backup and recovery operations to allow instantaneous backups, reduce recovery time, and simplify disaster recovery procedures while using less CPU, I/O, and storage resources.
IMS Recovery Expert integrates IBM FlashCopy® and other storage-based fast-replication services and exposes them to IMS DBAs in a transparent manner. IMS system-level backup methods are the foundation for these backup and recovery processes. IMS system-level backups that are performed using FlashCopy have many operational advantages:
- Backup, recovery, and disaster recovery procedures are simplified and costs are reduced.
- Application availability is increased because IMS systems can be backed up instantaneousy without affecting running applications. Backup windows are eliminated and application processing windows can be extended.
- FlashCopy operations are coordinated with IMS activities to back up IMS systems and validate that that all database resources are contained within the backup volumes.
- System-level backups reduce recovery time. IMS systems or application databases are restored instantaneously from a system-level backup using FlashCopy facilities while IMS recovery operations are performed in parallel to the restoration.
- IMS system-level backups provide an effective disaster restart business continuity solution that simplifies disaster recovery operations. Disaster recovery becomes as simple as restarting after a power failure.
Storage-aware IMS system-level backup solutions use volume-based FlashCopy operations to back up IMS systems. Volume-level backups have many operational advantages over data-set copy methods: They can be executed quickly, leverage storage-based consistency functions, and use storage processor resources efficiently.
When the IMS system volumes are discovered and backup target volumes are associated, FlashCopy facilities back up the IMS system instantaneously without affecting running applications. Backup volume and associated database recovery information is stored in a metadata repository and used during recovery and backup offload processing.
A- IMS system-level backup created by using volume-based FlashCopy
B- Disk-based system-level backup offloaded to tape
C- Disk-based-level backup used to restore an IMS system
D- IMS application or database recovery from a system-level backup
E- Restoring an IMS system or database from an offloaded system-level backup
Figure 1. IMS storage-aware database backup and recovery
A shows how IMS Recovery Expert uses volume-based FlashCopy to create a system-level backup for IMS.
Although IMS system-level backups on disk provide fast and effective restore recovery operations, maintaining multiple backup generations on disk can be costly. IMS Recovery Expert’s tape offload facilities provide long-term backup retention while allowing recovery from the archived copy.
B shows an IMS system-level backup that is archived to tape by IMS Recovery Expert. The archived copy can be used for subsequent IMS system, application, and database recovery.
IMS system-level backups are restored from disk or tape automatically when recovery operations are required. The recovery process determines which backup provides the optimal and most expeditious recovery: a disk-based IMS system-level backup or an IMS system-level backup.
In a disk-based IMS system-level backup, FlashCopy restores the data at a volume level to expedite the restoration process. IMS system recovery processes are performed in parallel during the restoration. Database logs are used to roll forward the restored application data.
C shows an IMS system recovery operation in which volume-based fast replication is used to restore database data. E shows an IMS system recovery from an IMS SLB that has been archived to tape.
When IMS applications or databases are recovered, appropriate corresponding data sets are restored from the system-level backup volumes by using data set FlashCopy facilities. Application recovery time is reduced because the data restoration process in the storage processor is performed in parallel with the IMS recovery processes. That is, IMS logs are applied while data is being restored in the storage processor as a result of the data set FlashCopy operation. The parallel restore and recovery processing reduces both overall recovery time and application downtime. D shows an IMS application or database recovery operation in which data-set-level fast replication is used to restore database data.
Intelligent Recovery Manager
IMS Recovery Expert has an embedded Intelligent Recovery Manager that coordinates and manages data restoration, recovery, and post recovery processes. The Intelligent Recovery Manager determines which SLB or image copy provides the most expedient recovery, and IMS Recovery Expert drives appropriate FlashCopy facilities to restore the data. You can configure recovery and post-recovery products and utilities to perform your recovery and post recovery processing needs.
Figure 2 shows the role of the Intelligent Recovery Manager in the recovery process.
Figure 2 IMS Recovery Expert Intelligent Recovery Manager
When IMS recovery is needed, the Intelligent Recovery Manager analyzes all available recovery assets and drives the recovery of an IMS system, application,or database in the most efficient manner. All recovery jobs are set up through an ISPF interface and all recovery utilities can be managed from a centralized point. Complex IMS recover processes are simplified, recovery steps are automated, and recovery time is reduced.
IMS Recovery Expert promotes parallel recovery operations by restoring backup copies while IMS recovery operations are performed in parallel. The Intelligent Recovery Manager invokes appropriate FlashCopy facilities and initiates IMS recovery procedures while data is being restored in the storage processor. Parallelizing the data restoration and IMS recovery processes shortens recovery time and reduces IMS recovery time objectives.
IMS Disaster Restart and Recovery
An IMS Recovery Expert-generated system-level backup simplifies disaster recovery operations and reduces recovery time objectives. You can use IMS system-level backups to restart the IMS system at a point in time when the backup was performed by using IMS emergency restart procedures. You can also roll forward IMS system-level backups by using available database logs and recovery assets at your disaster recovery site.
The Intelligent IMS Disaster Recovery Manager has both local and remote DR site components. The local component tracks IMS log archive processes and correlates them to IMS SLB creation and offsite transport. The remote DR site component provides facilities to roll the offsite IMS SLB forward using image copies, change accumulations, and archive logs that have been sent to the DR site. Tedious IMS disaster recovery operations can be transformed into efficient disaster restart procedures to simplify the IMS recovery process, reduce recovery time objectives, and reduce recovery point objectives at the disaster recovery site.
Offloading FlashCopy-based IMS system-level backups to tape and then transporting the tapes to a disaster recovery site provides the foundation for a tape-based disaster restart solution. Such solutions simplify disaster recovery operations, reduce recovery time objectives, and provide similar advantages to storage-based business continuity solutions that use remote storage replication such as IBM PPRC (peer-to-peer remote copy). Tape-based disaster restart solutions can provide an excellent and cost-effective tertiary disaster recovery solution when they are implemented with PPRC
Metro Mirror remote mirroring solutions.
For more information about IMS Recovery Expert for z/OS, visit www.ibm.com/software/data/ims/.