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how to replace disk which is mirrored in Open VMS

Regular Advisor

how to replace disk which is mirrored in Open VMS


we are facing problem in Aplha 4100 server. i am getting increasing error code on both disk in the mirror group. I am new to OVMS. i got new disks. but could you please tell me how to replace disk in the Open VMS.

Bob Blunt
Respected Contributor

Re: how to replace disk which is mirrored in Open VMS

Please give us some details about your configuration. There are several types of adapters and controllers that can be configured to mirror disks and OpenVMS has products called "shadowing" and "Host Based RAID" that allow similar setups.

The disk names may help some. Are your disk names (SHOW DEVICE D):


There are disk array controllers that can be connected to an AlphaServer 4100. Older ones are the HSJ, HSZ, HSD and HSG families and all "sit between" the Alpha and the disks you see. Fortunately those usually have unique device names so it isn't as hard to figure out what type array controller.
SCSI attached devices are a little more difficult because those disks are DK devices as are disks presented by the HSZ.

And all the different adapters and controllers have their own unique and special ways necessary to swap out failing or failed disks... So I hope you can see that we really need more information about your setup before we can lay the magic on you.

Andy Bustamante
Honored Contributor

Re: how to replace disk which is mirrored in Open VMS

As Bob asks, what is the configuration, including operating system version. Second, preserve your data with a backup. Copy critical files to another disk, create a tape backup or both. OpenVMS will generally provide warning before a disk failure, but if you have two disks in a raid-1 configuration generating errors, preserve that data first.

Depending on the disk configuration, consider adding a third disk or fourth member to the raid-1 set. Some configurations may not allow this gracefully.

If you don't have time to do it right, when will you have time to do it over? Reach me at first_name + "." + last_name at sysmanager net
Robert Gezelter
Honored Contributor

Re: how to replace disk which is mirrored in Open VMS


I will strongly concur with Andy's comment.

First, before anything else: Use BACKUP to preserve the contents of the entire system to a completely separate disk volume, tape, or CDROM/DVD.

Then, please provide precise details of the hardware configuration and how the volumes involved are configured. Note since both volumes in the mirror group are showing errors, it is possible that the problem does not lie with the drives themselves, but may be a controller or cable problem.

Once precise configuration information is available, the problem can be dealt with. However, I once again agree with Andy that the first critical step is to do that BACKUP. While drives can often be replaced without a shutdown, it depends on the hardware, and in inexperienced hands, a degree of risk; things can go wrong even in experienced hands.

Also consider getting access to experienced assistance [Disclosure: We provide such assistance, as do others who contribute to this forum]. Loss of data incidents are ruinously expensive.

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