Where Did All The DASD Go??

f you already know what is using up disk space on your AS/400, and are sure that your system has no garbage whatsoever on it, just turn the page and go on to the next article in the newsletter. However, if you wonder what is chewing up the disk space lately, and want to know if there is anything you ought to clean up before spending money (or begging for money) for new drives, keep reading.

Create a File

Start by creating a file that has information about every object on the system. At first, it may seem unreasonable to create a big file of information, when the point of the exercise is to reduce DASD usage. However, it is likely that you will save a lot more space than you use when monitoring DASD usage.

Another advantage of gathering all of your object information in one file is that you will then have the information available for running a series of specific housekeeping reports.

How to Create the File

Create this file in one of two ways. Use command DSPOBJD OBJ(*ALL/*ALL) OBJTYPE(*ALL) OUTFILE(mylib/myfile).

Alternatively, use GO DISKTASKS to get to the DISKTASKS menu and then Option 1. Collect Disk Space Information (RTVDSKINF) to collect information. The RTVDSKINF command will output the information to file QAEZDISK in library QUSRSYS.

When to Create the File

Both of the above commands will run for a long time, so run in batch, preferably off-hours. The first reason for running off-hours is obvious - to avoid annoying all the other system users and developers while you run a long tedious job.

The second reason for running in an off-hours time slot is that you can get incomplete information if objects are in use when you try to gather information on them.

Authority for Creating the File

For either RTVDSKINF or DSPOBJD, ensure that you have provided for sufficient authority to get all of the information you need. The AS/400 will give you information for only those objects to which you are authorized.

Commands that adopt authority can be helpful for this purpose. For example, if you use the command DSPOBJD as QPGMR, you will get only object descriptions that QPGMR is authorized to see. So, create a command and command-processing program called, for example, ALLOBJD. Have QSECOFR compile these new objects with USRPRF(*OWNER). When you use the command ALLOBJD, you will get object descriptions for all objects, without the inconvenience of requiring QSECOFR to always submit the command, or the security problem of giving QPGMR permanent authority to all objects.

Create Reports

Now that you have a file with information on every object, what you do to create reports depends on which way you gathered the information in the first place.

If you used the DISKTASKS menu, then you can use Option 2. Print Disk Space Information (PRTDSKINF) on the same menu. The PRTDSKINF command allows you to create custom reports by library, or by folder, or by object. It also allows some selection based on object or library size, to provide only the information that is most likely to be interesting.

If you used DSPOBJD to create the file of information (or if you used RTVDSKINF, but want additional reports or a different format than that available in PRTDSKINF) you can use query to summarize by library, or to sort by size, or to select libraries or objects of a certain size and print reports.

Summarize in File

A small summary file can be handy for future reference. If you create a summary file with one record per library to record the library name and the total storage used by the library, you will have the ability to do a quick comparison next week when you re-run and summarize, and highlight the major changes immediately.

Unused Objects

Unused objects information can be very helpful. In both files (through DISKTASKS and DSPOBJD) the last change and the last used dates for every object are provided. By comparing those dates to your run date, you can determine if you have any objects that may be obsolete, and therefore wasting disk space.

Now What?

Now that you know where storage is being used unnecessarily, and where the largest, most useless objects are located, all that's left to do is to employ a little friendly persuasion, to encourage those responsible to tidy up! T < G