Using Incremental IFS Backup To Speed Up Backup Time
March 20, 2013 Hey, Joe
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Is there a trick to speeding up AS/400 Integrated File System (IFS) nightly backups? My nightly backups run over 300 minutes and 120 of those minutes are tied to the IFS backup, so it runs into production hours. Here’s the Save (SAV) command I’m using to backup the IFS.
SAV DEV('/QSYS.LIB/TAP01.DEVD') OBJ(('/*') +
('/QSYS.LIB' *OMIT) ('/QDLS' *OMIT)) +
SAVACT(*SYNC) ENDOPT(*UNLOAD) +
UPDHST(*YES) DTACPR(*DEV)
— C To cut down on IFS backup times, you can modify your backups to perform a full IFS backup once a week and an incremental backup the other nights of the week. Here’s how this works. 1. Perform a weekly full IFS backup, at a time where longer processing times won’t affect system performance (say Sunday morning at 3 a.m). Use the same command you sent me.
SAV DEV('/QSYS.LIB/TAP01.DEVD') OBJ(('/*') +
('/QSYS.LIB' *OMIT) ('/QDLS' *OMIT)) +
SAVACT(*SYNC) ENDOPT(*UNLOAD) +
UPDHST(*YES) DTACPR(*DEV)
This backup will take the same amount of time as the backups you’re performing now, but you’ll only be running it once a week during off-hours. One thing to note: Make sure that the Update History (UPDHST) parameter stays at its current value of *YES. This tells the system to update the save history (archive bit) of all objects that were saved with the SAV command. This is important because your object’s save history will be used in the incremental backup I’ll explain next. 2. Use the SAV command below to perform an incremental backup on the other days of the week. Call this the daily backup. This backup command will only save the IFS files that were changed since the last full backup.
SAV DEV('/QSYS.LIB/TAP01.DEVD') OBJ(('/*')
('/QSYS.LIB' *OMIT) ('/QDLS' *OMIT))
SAVACT(*SYNC) ENDOPT(*UNLOAD) CHGPERIOD(*LASTSAVE)
UPDHST(*NO)
DTACPR(*DEV)
This incremental backup depends on the following two parameters.
Since this command is only saving changed objects since the last full backup, it will run a lot faster than the weekly full IFS backup. What’s more, since you’re not updating the object date and time archive bit, this SAV command will always backup ALL the objects that have changed since your last weekly save. Each daily tape will be a complete incremental backup of all changed objects since the last full IFS save in step 1. The end result is that you have both a full and an incremental backup of the IFS. If you needed to restore the entire IFS, you would restore from the full system backup first, and then restore the most recently changed objects from the latest incremental backup. Determining Whether An IFS Object Has Been Modified You can also use either the green screen or System i Navigator to determine if an IFS object has been updated since the last time it was backed up. From the green screen, use the Work with Object Links (WRKLNK) command to navigate to the object you want to check. Place an ‘8’=Display Attributes in front of the object and press ENTER. This will display the following Display Attributes screen.
(Click graphic to enlarge.) Look at the Need to archive (System) line on this screen. This setting is the archive bit. If it is set to ‘Yes’, the IFS object has been changed since the last backup. If set to ‘No’, the object has not changed. To view an object’s archive bit in the System i Navigator package that comes with IBM i Access for Windows 7.1, open the File Systems→Integrated File System→Root path for your target partition. Navigate to the object you want to check the archive bit for and right-click on that object. Select Properties from the pop-up menu that appears. Click on the General tab of the Properties screen for your object. You’ll see a screen that looks something like this.
Look at the Archive check box under the i5/OS area. If Archive is checked, that object has changed since the last full IFS backup. If the Archive check box is unchecked, the object has not changed since the backup. HTH –Joe EDITOR’S NOTE: This tip was tested with the SAV command that comes with the IBM i 6.1.1 operating system and the System i Navigator program that is included with IBM i Access for Windows 7.1. Follow Me On My Blog, On Twitter, And On LinkedIn Check out my blog at joehertvik.com, where I focus on computer administration and news (especially IBM i); vendor, marketing, and tech writing news and materials; and whatever else I come across. You can also follow me on Twitter @JoeHertvik and on LinkedIn. Joe Hertvik is the owner of Hertvik Business Services, a service company that provides written marketing content and presentation services for the computer industry, including white papers, case studies, and other marketing material. Email Joe for a free quote for any upcoming projects. He also runs a data center for two companies outside Chicago. Joe is a contributing editor for IT Jungle and has written the Admin Alert column since 2002.
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