SAP on IBM i – Update week 33, 2016: Online Backup Improvements with IBM i 7.3
Today’s globalized environment requires your productive SAP system to stay up and running 24 hours a day for 7 days a week all year round. Maintenance windows are hard to obtain, so it is important that you can back up your SAP database and application data while the SAP system is staying up and running. A new feature in IBM i 7.3 makes this task easier to accomplish.
Since many years, IBM i has offered full online backup capabilities for the database with the *NOCMTBDY option for parameter SAVACTWAIT on the save commands for libraries and objects. However, saving integrated file system data (directories and files in directories) could prove challenging for busy systems. This was not considered a huge problem, because in most cases only data was affected that was not critical to your business, such as log files or temporary files that were rebuild at system restart anyway. However, you could still encounter problems in one of the following ways:
- You may have had problems starting background jobs or creating spooled output in your SAP system while a backup was running (Unable to open file, error 16).
- You may have had problems opening secondary database connections in a work process while a backup was running (CPDA0FF – XDNFileTokenAuth::SendChallenge: WriteTokenFile Failed).
- You may have received error messages from your backup job (CPFA09E – Object in use and CPF3837 – <x> objects saved. <y> objects not saved).
In the past, SAP has documented these cases in SAP Note 825473 (IBM i: Online backup from V5R3M0) and SAP Note 1695963 (DB4/XDN: Token File Prefix). The “allow write during save” attribute for integrated file system objects would help avoid some of these issues, but this attribute had to be set before opening the file and could not be used on directories. You could also workaround those problems by excluding a list of directories and files with temporary data from the backup.
With IBM i 7.3, the operating system has been enhanced to allow write operations during save for both directories and files in the integrated file system, and directories can be configured so that objects created in those directories inherit their attributes from the parent directory. With that, a true online backup of integrated file system data is possible.
When your system is running IBM i 7.3, you can setup your SAP system for allowing online backups simply by running the following four commands once:
CHGATR OBJ(‘/usr/sap/<sid>/*’) ATR(*ALWCKPWRT) VALUE(*YES) SUBTREE(*ALL) SYMLNK(*YES)
CHGATR OBJ(‘/usr/sap/<sid>/*’) ATR(*INHCKPWRT) VALUE(*YES) SUBTREE(*ALL) SYMLNK(*YES)
CHGATR OBJ(‘/sapmnt/<sid>/*’) ATR(*ALWCKPWRT) VALUE(*YES) SUBTREE(*ALL) SYMLNK(*YES)
CHGATR OBJ(‘/sapmnt/<sid>/*’) ATR(*INHCKPWRT) VALUE(*YES) SUBTREE(*ALL) SYMLNK(*YES)
Replace <sid> with the 3-character SAP system ID of your system. If your system is configured to run in an independent auxiliary storage pool (IASP), you need to add the IASP device name to the beginning of the path names. Once you have run these commands, you can use the options SAVACT(*YES) SAVACTOPT(*ALWCKPWRT) on the SAV command in order to save your integrated file system data while your SAP system stays up and running.