SFHA Solutions 6.0.1: Understanding the udid_mismatch flag
Beginning with the Veritas Storage Foundation and High Availability release 5.0, a unique disk identifier (UDID) is added to the disk's private region when the disk is initialized or when the disk is imported into a disk group (if this identifier does not already exist). When a disk is brought online, the current UDID value that is known to the Device Discovery Layer (DDL) is compared with the UDID that is set in the disk’s private region. If the UDID values do not
match, the udid_mismatch flag is set on the disk. This usually means that the disk has been copied from another disk. For example, a disk may be copied by creating a hardware snapshot or clone, by using dd or some other command to replicate the disk, or by building a new logical unit (also known as a LUN or virtual disk device) from the space that was previously used by a deleted LUN. Duplicated disks are prevented from being imported to avoid duplicate disk IDs. The vxdisk list command displays the udid_mismatch flag in the event that the UDID values do not match.
For information on the udid_mismatch flag, see:
- Handling cloned disks with duplicated identifiers
- Writing a new UDID to a disk
- Importing a disk group containing cloned disks
- Sample cases of operations on cloned disks
- Clearing the udid_mismatch flag for non-clone disks
For information on what the udid_mismatch flag indicates, and how to solve mismatches, see:
Information regarding the udid_mismatch flag can also be found in the PDF versions of the following guides:
- Veritas Storage Foundation Cluster File System High Availability Administrator's Guide
- Veritas Storage Foundation and High Availability Solutions Troubleshooting Guide
vxdisk (1M) 6.0.1 manual pages:
vxdisk (1M) manual pages and Veritas Storage Foundation and High Availability documentation for other platforms and releases can be found on the SORT website.