Backup And Restore

10 pts.
Tags:
AS/400 backup
AS/400 backup and recovery
Backup and restore
SAVF
Virtual backups
I'm trying to find the fastest way to backup a library amongst others and restore it to a new library in order to make it available for inquiry mode while the production library is available for Monthend processing. Currently the process is to do a backup of a few libraries (approx.2.5 hrs) and then restore one library from tape (approx. 2.5 hrs) to a new library called xxxxOLD.A cpylib command takes longer than the enire backup. Is there a faster way to do this? Is it faster to backup to virtual tape or SAVF and then restore to the new library plus back it up to tape? Space is a factor since restoring the library adds 10% to the ASP from 77% to 87%.

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The fastest way to backup and restore the libraries would be with a disk to disk backup system connected by 10 GBE, which would cost about 10K and require a Windows server. It doesn’t use any disk space on the AS/400 and it will run up to ten times faster than LTO3, depending on your hosts ability to save and restore the data.

Brad Jensen
Laservault

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Hi,

I suspect saving and restoring to save files will be quicker, but will take up more disk space. Depending on how many logicals and the size of your files (and the speed of your system), it may speed things up if you don’t save access paths and let the system rebuild them after the restore.

Do you use journalling? It may help if you un-journal your files first and re-journal them after, if you can get a window when the data is not in use.

Regards,

Martin Gilbert.

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So what you want to do is really to make available a copy of a library as at a point in time?

Duplicate the library and rename it by using Copy, – can I assume that users do not need to update anything? – remove all update rights so they do not create locks, then take a backup of the copied library.

Or why not use Save while active – this establishes a checkpoint on the library, and does the backup. Beware that it could take an age longer to establish a library wide checkpoint, and I have to say that I’ve not been on a site where I was aware of it being used in anger.

If your aim is to create a library called xxxOLD, then save/restore is a waste of time. Copy the one library you need and give it to users. Do the saves as a separate question.

If you write a bit of CL both processes can run concurrently – again, lets make an assumption that you have everyone off the box. begin by handling the xxxOLD issue by spawning a job running CPYLIB, then begin a backup of all other libraries. You say the overall process takes 2+ hours, so after saving all other libraries, check if your CPYLIB job has ended, and if so, save that library. You now have all libraries saved and your xxxOLD library.

I recommend some experimentation, and in particular examine the metrics from performance information, or old joblogs to see the timings for the individual library saves. You may also care to conduct some timings on the speed of CRTDUPOBJ (library) versus CPYLIB (Library)
Both of these should be faster by an order of magnitude than a save/restore. If you have disk space, then always do a savobj to disk, then copy to tape (if we’re talking real tapes) – peripheral data transfer is almost always fastest to disk, as that’s the channel that gets optimised the most.

Yorkshireman
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If its for just quering .. you could use DDM files.

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  • DanD
    You would have to test to be sure it is quicker, but you could make this a one step process by doing a dspobjd to an outfile the having a program read the outfile and crtdupobj for all of the objects. You might have an if statement for *files that says if the otype eq '*file the command includes Duplicate Data *yes. You could also have this submit each dupe as a batch job so you could copy mulitple objects at once. With either method, be careful of logical files pointing to the original object not the restored or duped object.
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