I/O Error on DASD Device

[kabrahams]

Good day,

We did a DR test a week ago and have four partitions - No sysplex but have SHARE volumes that can be accessed from all the partitions.
When IPLing the "DR" partition one of the volumes where left online to the other systems and now when trying to vary it online we getting an I/O error on the device.
Message received.
V 961E,ONLINE
IEF503I UNIT 961E I/O ERROR

Kind regards
Karl Abrahams

[Robert Sample]

The error message explanation tells you

System programmer response
If the volume should use a non-standard label, ensure that a non-standard label handling routine exists. Otherwise, provide a standard label for the volume.
If the system issued this message for a DASD, ensure that the device is functioning correctly. Verify that the device has a correct standard label. If necessary:
Refresh the volume label and try to vary the device online so that the system can attempt to verify the volume serial number.
If the device is mountable, you also can replace the volume with one having a standard label.
Try to vary the device online so that the system can attempt to verify the volume serial. Further errors can indicate that the device experienced a hardware failure; in this case, contact hardware support.

It sounds like the volume needs to be re-initialized.