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Our OpenVMS 8.3 ODS-5 machines, disks mounted as shadow set members sometimes lose freeblocks suddenly with no obvious cause. Adding up the FREEBLOCKS and the total size of all files on the disk gives a much lower total than the actual total available blocks on the disk. Can anyone suggest what might be causing this?

I have found that purging files will usually eliminate the issue but have no explanation for it and cannot find the file(s) causing it.

The machine is not in a cluster and ANALYZE/RMS told me, and others whom I consulted, nothing. All file versions were considered but it may be that dir/size needs to be qualified further. I am not aware of any temporary/scratch files but ideally I would like to find them if they exist. The shortfall between TOTALBLOCK-FREEBLOCKS and the output of dir/siz/grand [000000...] was approx 60 million blocks (about half the drive).

I am unfamiliar with DFU.

David Hoelzer
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user3602462
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  • Use DIR/SIZE=ALLOCATION or DIR/SIZE=ALL. The command you show only shows the 'USED' blocks', not the pre-allocated block. Pre-allocation can be deliberate by the program, or unavoidable due to CLUSTERSIZE round up. Google: openvms dfu download. If you are serious about files and allocation and freespace then DFU is a MUST HAVE. – Hein May 06 '14 at 10:15

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  • Don't worry. be happy. It is sure NOT to be a problem just a lack of understanding. ( Of course one could consider that in and of itself a bigger problem than an apparent mismatch in numbers. :-)

  • "Much lower" is almost meaningless. Everything is relative. How about some quantitative numbers.

  • Is this a cluster? Each cluster member can, and will have its own extend cache, possibly 10% of the free space each. Did you flush that/those before counting?

  • Were the ALLOCATED blocks counted, as one should, or perhaps just used blocks?

  • Were all versions of all files included in the count (since purge possibly changed the result)

  • Do the application on the system use TEMPORARY files which are not entered into a directory, and thus possibly not counted?

  • Have you considered enabling DISK QUOTA, just for the count, not to limit usage?

  • How about ANALYZE / DISK?

  • How about poking at the drive with DFU... highly recommended! Likely "Much faster" :-), and "Much more accurate" than anything DIRECTORY based.

Regards, Hein.

Hein
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  • Point #4. Command used was "dir/siz/grand" should be "dir/siz=ALL/grand" but really should be DFU REPORT xxx: – Hein May 06 '14 at 10:18