[Info-vax] VMS defragmenters

[etmsreec at yahoo.co.uk]

On 14 Apr, 20:39, JF Mezei <jfmezei.spam... at vaxination.ca> wrote:
> This is worth its own topic.
>
> There was a fragmentation analyser on a decus tape last millenia.
>
> And there has been COPY/CONTIGUOUS for many eons which allowed
> individual files to be defragmented.
>
> But with more recent VMS versions, wasn't there a "built-in"
> defragmenter ? If not, what is the SET FILE/MOVE/NOMOVE used for ?

SET FILE/NOMOVE is there so that defragmentation tools (of which there
are a number - 2 that I know of) don't try to move the file in
question.
The HP Defragmentation tool (Disk File Optimiser) requires you to make
sure that you've set the right files to NOMOVE and won't run unless
you say "Yes" to the question of whether you've run the command
procedure that goes round and puts the right flag on all of the files
it's interested in.  the awkward thing for a running system is that
some of the files that it tries to set NOMOVE on won't allow you to if
you're booted from that disk.  Go figure.

PerfectDisk is still about, though Ultradisk has not and, reportedly,
will not be ported to VMS on Integrity.  This means that whichever
defrag tool you're looking at is likely to need you to shut down any
applications on the disk that you're defragging.  Not great for a
production environment but it's safest I guess.

Steve