VERITAS Storage Foundation 4.1 Cross-Platform Data Sharing Administrator's Guide
Chapter 3, Maintaining Your System
Disk Tasks
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If two of the three labels are intact, the disk is still recognized as a cdsdisk (though in the 'error'
state) and vxdisk flush can be used to restore the CDS disk labels from their backup copies.
Primary labels are at sectors 0, 7, and 16; and a normal flush will not flush sectors 7 and 16. Also,
the private area is not updated as the disk is not in a disk group. There is no means of finding a
“good” private region to flush from. In this case, it is possible to restore the CDS disk labels from
the existing backups on disk using the flush operation.
If a corruption happened after the labels were read and the disk is still online and part of a disk
group, then a flush operation will also flush the private region.
Caution Caution and knowledge must be employed because the damage could involve more than
the CDS disk labels. If the damage is constrained to the first 128K (as would be the case
if some entity on the fabric - such as a Windows box - wrote a disk label to a disk which
was actually a cdsdisk being used in some disk group), then the disk flush would fix
it.
Use the following command to rewrite the CDS ID information to a specific disk (this rewrites all
labels except sectors 7 and 16):
# vxdisk flush disk_accessname
Use the following command to rewrite all the disks in a CDS disk group (this rewrites all labels
except sectors 7 and 16):
# vxdg flush dg_name
Use the -f option with the vxdisk command to forcibly rewrite the AIX coexistence label (sector
7), VxVM ID block (sector 16), and HP-UX Coexistence Labels:
# vxdisk -f flush disk_accessname
This command rewrites all labels if there exists a valid VxVM ID block that points to a valid
private region.
Note Sectors 7 and 16 are only rewritten if the -f flag is given. The reason for this is that these
sectors lay within the first track of the disk, and Windows systems use the first track for their
own purposes. In the example above where the disk was taken offline due to label
corruption, if it involved sectors 7 or 16, then -f is required to fix the problem.