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Can 7.3-2 expand disk on the fly?

Robert Brothers
Frequent Advisor

Can 7.3-2 expand disk on the fly?

An EVA5000 has the ability to expand a disk on the fly can VMS do the same?
Robert Gezelter
Honored Contributor

Re: Can 7.3-2 expand disk on the fly?


Within limits, the answer is yes.

Rather than make an extended posting, I suggest that you go through my presentation " Migrating OpenVMS Storage Environments without Interruption or Disruption", presented at the 2007 HP Enterprise Technology Forum in Las Vegas. The slides are available at: http://www.rlgsc.com/hptechnologyforum/2007/1512.html

Unless things are already set up in this vein, it will be necessary to momentarily interrupt operations to set the needed settings. After that, as shown in the presentation, expansion can be done during normal operation.

- Bob Gezelter, http://www.rlgsc.com
Honored Contributor

Re: Can 7.3-2 expand disk on the fly?

Yes, dynamic volume expansion (DVE) and its cousin dissimilar device shadowing (DDS) are available here.

Do get and do load the current ECOs for your (comparatively old) OpenVMS Alpha V7.3-2 version, too -- there are various mandatory ECOs around I/O, DVE and DDS.

As Bob G. quite correctly indicates, information on implementing DVE and DDS is available, as are pointers to a couple of the relevant kinks here such as the incorrect handling of DVE disks with the OpenVMS Alpha V7.3-2 distribution CD -- use of the V8.2 and later installation disks work rather better here when restoring or managing DVE disks, even for BACKUP /IMAGE copies of the V7.3-2 bits. In addition to Bob's materials, there are various presentations and manuals on this topic, including the manuals at:


The OpenVMS patches are available at:


Load all of the mandatory patches.

And you will have to dismount the DVE disk once -- and mount it privately -- to first enable this feature. Subsequent expansions can be online, and with no dismount required.