topic Re: analyze/disk/usage 1 block off in allocated size in Operating System - OpenVMS

analyze/disk/usage 1 block off in allocated size

SDIH1 — Thu, 05 Mar 2009 15:15:43 GMT

Hi,

Did anyone ever notice that in the output of anlyze/disk/usage the allocated block count is always 1 higher than what e.g. directory gives with a dir/size=all?

The minimum space allocated according to this utility is 1 block, never 0.
The workaround is simple: subtract 1 off the allocated size.

The used block count does not suffer from this peculiar offset of 1.

Re: analyze/disk/usage 1 block off in allocated size

Hoff — Thu, 05 Mar 2009 15:18:23 GMT

Contact HP support, and let them know.

Re: analyze/disk/usage 1 block off in allocated size

SDIH1 — Thu, 05 Mar 2009 15:39:52 GMT

Ok, just confirming it's not a feature I had missed.

Re: analyze/disk/usage 1 block off in allocated size

Hein van den Heuvel — Thu, 05 Mar 2009 15:49:24 GMT

Disk quota should, and apparently will, count the FILE HEADER as a block. That's a block you use, even though it has no datat.
As you know, heavily fragmented, or heavily ACLed files may need more than 1 header.

Cheers,
Hein.

Re: analyze/disk/usage 1 block off in allocated size

Hein van den Heuvel — Fri, 13 Mar 2009 13:31:14 GMT

So.. was the file header block indeed the explanation? That would suggest 1 per file (at least) and you mentioned just a single 1.
Maybe the test was with just 1 file?

Hein.

(stuur eens een Email?)

Re: analyze/disk/usage 1 block off in allocated size

SDIH1 — Tue, 21 Jul 2009 14:50:08 GMT

Better late than never:

Yes, the file header was the culprit, mainly to accommodate for disk quota to function properly. For 'entered' files as found on the system disk this gives interesting results, as there you have multiple file headers but only one allocated size.

Re: analyze/disk/usage 1 block off in allocated size

Hein van den Heuvel — Tue, 21 Jul 2009 18:33:20 GMT

>>>> For 'entered' files as found on the system disk this gives interesting results, as there you have multiple file headers but only one allocated size.

Nitpicking...

'Entered' files (SET FILE/ENTER) have additional DIRECTORY ENTRIES, but they all have the same File-ID pointing to one and the same file header.

Of course the directory _might_ grow a block as a new file is entered.

Hein

Re: analyze/disk/usage 1 block off in allocated size

SDIH1 — Wed, 22 Jul 2009 12:31:21 GMT

I stand corrected.

The little project I wanted to use this for (making a treemap a la Sequoia (Google) of a VMS disk ) proved to have performance issues on the graphical side anyway. Without tweaking more than I wanted to there was hardly a satisfying user experience, to coin a phrase.

I am closing this thread. Thanks everyone!

Re: analyze/disk/usage 1 block off in allocated size

SDIH1 — Wed, 22 Jul 2009 12:31:53 GMT

Closed