Hi Again, As you can imagine, over the years our L2 folks have been called out to help recover data after many an 'oops'. In many cases, there isn't a backup for all of the data, which has resulted in data loss. Hence, most will concur that any backup is better than no backup.
For the case of backing up Online Systems, investigate what the applications themselves offer. In the case of DB2, DB2 and DFSMS have worked together to create a Continuous Data Protection solution (CDP) through the DB2 BACKUP SYSTEM / RESTORE SYSTEM utilities. BACKUP SYSTEM creates a fuzzy backup that can be made consistent during recovery through Log Applies. In order to create a consistent recovery, creates/renames/deletes/extended must be quiesced during the backup, but data updates are allowed to continue. (Essentially VTOC updates are held to ensure that the VTOCs are data consistent). DB2 invokes DFSMShsm to create FlashCopy PiT backups (FRBACKUP). During Recovery, the client selects the recovery point, which can be 'current', or a prior point in time. DFSMShsm recovers the PiT copy using FlashCopy (if still on disk) or from Tape (if the backup copy has rolled off to tape). DB2 then performs a log apply up to the recovery point, creating a data consistent recovery. Some clients also use this process to create Clones. When this CDP solution is combined with Metro Mirror, there is a very high level of protection from both physical and logical loss. This solution can also be used for SAP systems, when DB2 is the database. Glenn Wilcock DFSMShsm Architect ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
