Limitation on number of versions within VMS?

[Jorge Cocomess]

Hi,

Sorry for asking this dumb question, but I must find out;
Is there a limit on how many version can you within a single directory? What's the default value for numbe rof versions if you don't set to a value (version=7).

Thanks,
J

[John Gillings · Accepted solution]

Jorge,

The ultimate limit for versions is 32767. If a file with ;32767 exists you cannot create a new version.

The default version limit for a file is the default for the directory. See SET DIRECTORY/VERSION. It's displayed by DIRECTORY/FULL of the directory file.

There is no "default default" so a directory with no version limit is really 32767. A new directory will inherit the version limit of its parent.

[Jan van den Ende]

Jorge,

maybe superfluous, but I think I understand from your question that you are still very inexperienced in VMS, so let me elaborate on Johns answer.


The ultimate limit for versions is 32767. If a file with ;32767 exists you cannot create a new version.

The default version limit for a file is the default for the directory. See SET DIRECTORY/VERSION. It's displayed by DIRECTORY/FULL of the directory file.


This is entirely correct, but fails to mention the big difference between the default, hard limit and the settable limit.

IF version ;32767 is present, there is NO way that you create the next version. (although, if not all 32767 versions are present, it IS possible to specifically address a non-existing version and create THAT).
If however a version limit is set, and you try to create the next version, then first the lowest version will have to be deleted. Ie, a DELETE for it will be issued, and that must succeed (locking & protection must allow it) before the next higher version will be created.

The mechanism is not unlike a M$ or U*X creation of an existing file: you must be able to delete that one before the create can succeed.
In a way, M$ and U*X can be considered to have a hard-coded version limit of 1. :-)

hth,

Proost.

Have one on me.

jpe

[Jorge Cocomess]

Thank you. This is exactly the answers taht I was hoping for.

Cheers.

J

[Arch_Muthiah]

Jorge,

If it is ODS-1 (VAX only), the max version is 32,767; version limits are not supported.

Also you may be known this....
if you SET the version limit to 3 when there are already 5 versions of that file in your dire, the version limit continue to be 5 unless you specifically delete or purge the files.

Archunan

[Thomas Ritter]

Jorge, knowing this magical number is good, but addtionally as a system manager you will need to have in place procedures to detect files which are reaching this number. It is usually not obvious when a process fails as a result of 32767.

We use DFU inside a command procedure.

$ dfu search /version=mini=30000

As version numbers exceed 30000 we commence and investigation.

Thomas

[John Gillings]

>We use DFU inside a command procedure.
>
>$ dfu search /version=mini=30000
>
>As version numbers exceed 30000 we
>commence and investigation.

As of V8.2, the DIRECTORY command can do this too:

$ DIRECTORY/SELECT=VERSION=MINIMUM=number
$ DIRECTORY/SELECT=VERSION=MAXIMUM=number

A neat trick for "resetting" the version sequence of a filename:

$ RENAME file.type;* file_type.TMP;
$ RENAME file_type.TMP;* file.type;

This will renumber all versions of a file to start at 1, preserving the order of the original files. Note the wildcards and semicolons, they are critical.

Be a bit careful as there are potential timing windows if other processes are creating or deleting files while the RENAMEs are proceeding.

[Jiri_5]

For resetin version number I use command:

$RENAME file.type; file.type;

but it's work only when in directory is only one (last) versin of file


Jirza