[Info-vax] OpenVMS - file selection abnormally with Copy / Rename or user ignorance?

[Stephen Hoffman]

On 2015-03-28 20:14:16 +0000, JF Mezei said:

> On 15-03-28 16:00, Michael Moroney wrote:
> 
>> It bypasses the usual VMS file locking mechanism so that the contents
>> BACKUP gets may not be consistent as a writer may be asynchronously
>> writing or changing data.
> 
> But Backup/ignore-=interlock does issue a warning when it encounters a 
> file currently opened for write by another process.
> 
> Hoff mentioned that those reports are not "complete".  So was wondering
> under what circumstances Backup would NOT report a potential for the log
> file not having indication that a file may have inconsistent data.

AFAIK, the circumstances are not officially documented.

This because there's no upside to discussing the details.

>From the OpenVMS documentation:


                                    NOTE

        File system interlocks are expressly designed to prevent
        data corruptions, and to allow applications to detect and
        report data access conflicts.

        Use of the INTERLOCK keyword overrides these file data
        integrity interlocks. The data that BACKUP subsequently
        transfers can then contain corrupted data for open files.
        Also, all cases in which these data corruptions can occur
        in the data that BACKUP transfers are not reliably reported
        to you; in other words, silent data corruptions are possible
        within the transferred data."




-- 
Pure Personal Opinion | HoffmanLabs LLC