OpenVMS 8.3 backing Up the system disk(member of a shadow Set) - best way

[michaelk1]

Hi @ALL,

i've got an integrity Server running 8.3. I would Like to Back Up the system disk, which is a member of a shadow Set.

Usually i would do IT via standalone backup/Image to Not Run Info open file problems.

But due to the fact, the machine is a production system, so I cannot shut down the system.

For redundancy i usually use RAID subsystems. So I worked around the volume shadowing service..

My Idea is: i take a new disk, Put IT in the system disks shadow Set, wait for copy completion and dismount it, to get it out of the shadow set.

Any suggestions or hints?

I should bei pleased receiving any Help from you.

cua.

[support_s]

System recommended content:

1. OpenVMS Alpha - v 7.3.2 or up Fails to Dump Error Log Buffers to Remaining Shadow Set Members during Shutdown

Please click on "Thumbs Up/Kudo" icon to give a "Kudo".

Thank you for being a HPE valuable community member.

[michaelk1]

Hi,

sorry, but how can that help me in any way?

[Steven Schweda]

> [...] So I worked around the volume shadowing service..

   I don't know what that means.

> My Idea is: [...]

   I've never used volume shadowing, so I know nothing, but I believe
that this is a pretty standard technique.  A Web search for terms like:
      openvms shadow set backup
should find many things, including the Volume Shadowing Guide:

      https://vmssoftware.com/docs/VSI_VOLUME_SHAD_GD.pdf

In that guide, see, for example:

    4.10.4. Dismounting and Remounting With One Less Member for Backup
    7.12. Guidelines for Using a Shadow Set Member for Backup

> sorry, but how can that help me in any way?

   "support_s System Recommended" is a computer program which often
provides very poor advice.  (It knows even less than I do about this
topic.)  It asks for praise, but can't accept negative criticism, which
says much about its quality.

[michaelk1]

Hi Steven,

thanks for the information.

What i meant with "workaround" is, that i used hardware replication instead of software, which is a little bit slower. So i worked around Volume Shadowing using RAID. So my knowledge regarding volume shadowing is a little bit poor, but the links you told me, were in use by myself for a while. But there could be any hints regarding Volume shadowing, which I don't know. Thats the reason for this post.

cu
Michael

[Steven Schweda]

> [...] i worked around Volume Shadowing using RAID. [...]

Ok. Again, I have no actual experience, but I'd expect the same
basic method to work using hardware RAID or software volume shadowing.

> [...] But there could be any hints regarding Volume shadowing, which I
> don't know. [...]

   "hints"?  Do you have any specific questions?

   I still know nothing, but I'd start with that suggested Web search
(or a similar Forum search).  I'm confident that I've seen this
discussed here and on comp.os.vms many times over many years.  There's
also a VSI forum, which might have a bigger audience these days:

      https://forum.vmssoftware.com/index.php

[michaelk1]

Any hints, Well, i mean: are there any known Bugs within the usage of volume shadowing?

[Steven Schweda]

> [...] are there any known Bugs within the usage of volume shadowing?

   I don't use it, so I'd be unlikely to know, but it's a supported
product.  I'd expect people who use it to be more interested in data
integrity than people who don't, so I'd expect any bugs to get reported
and fixed promptly.  Again, I'd expect a Web/Forum search to find
complaints about such problems.

   Of course, V8.3 is not the latest VMS version.

[Volker Halle]

michaelk1,

if your system disk is a member of a shadowset, you could add another member to it with a shadow-copy operation. That new member must be the same size or bigger:

$ MOUNT/SYS/CONFIRM DSAx: label_of_system_disk/SHAD=name_of_new_disk

Once the shadow-copy has finished, you can dismount that member again with

$ DISMOUNT name_of_new_disk

Be aware, that the general problem of data consistency can not be solved by this method. It's about the same possible inconsistency as you get with BACKUP/IMAGE/IGNORE=INTERLOCK

Depending on what kind of files/databases etc. are on your system disk, the fact that you now have created a bootable backup of your system disk may outweight the fact, that some files may not be 100% consistent. 

Volker.