Friday Fine-Tune: Cleaning Up Correctly
June 16, 2017
Classic 3000 Advice
By John Burke
Good intentions about maintenance sometimes stumble in their implementation. As an example, here’s a request for help on cleaning up.
“We have a 989/650 system. Every weekend we identify about 70,000 files to delete off the system. I build a jobstream that basically executes a file that has about 70 thousand lines. Each line says ‘PURGE file.group.account’. This job has become a real hog. It launches at 6 AM on Sunday morning, but by 7 PM on Sunday night it has only purged about 20,000 files. While this job is running, logons take upwards of 30 seconds. What can I do?”
This reminds me of the old joke where the guy goes to the doctor and complains “Gee, doc, my arm hurts like hell when I move it like this. What can I do?” The doctor looks at him and says “Stop moving it like that.” But seriously, the user above is lucky the files are not all in the same group or he would be experiencing system failures like the poor user two years ago who was only trying to purge 40,000 files.
In either case, the advice is the same; purge the files in reverse alphabetic order. This will avoid a system failure if you already have too many files in a group or HFS directory, and it will dramatically improve system performance in all cases. However, several people on the 3000-L list have pointed out that if you find you need to purge 70,000 files per week, you should consider altering your procedures to use temporary files. Or if that will not work, purge the files as soon as you no longer need them rather than wait until it becomes a huge task.
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