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vxdco [-g diskgroup] attlogvol dco dco_volume
vxdco [-g diskgroup] [-o rm] dis dco
vxdco [-g diskgroup] [-o rm] dislogvol dco
vxdco [-g diskgroup] -o force enable dco
The vxdco command is used to manipulate version 0 data change objects (DCO objects or DCOs) and DCO volumes that allow the use of Persistent FastResync with volumes.
The att operation attaches a DCO object, dco, to a volume, volume. If the DCO object has an associated DCO volume, you can use the command vxvol set fmr=on volume to enable Persistent FastResync on the volume after the att operation has completed.
The attlogvol operation associates a DCO volume, dco_volume, with a DCO object, dco. If the DCO object is already attached to a volume, you can use the command vxvol set fmr=on volume to enable Persistent FastResync on the volume after the attlogvol operation has completed.
The dis operation dissociates a DCO object, dco, from a volume, and disables FastResync on that volume. If the -o rm option is specified, the DCO object, the DCO volume, its plexes and associated subdisks are removed in the same operation.
The dislogvol operation dissociates a DCO volume from a DCO object, dco, and disables FastResync on the parent volume. If the -o rm option is specified, the DCO volume, its plexes and associated subdisks are removed in the same operation.
If an error occurs while reading or writing a DCO volume, it is detached and the badlog flag is set on the DCO. (You can use one of the options -a, -F or -m to vxprint to check if the badlog flag is set on a DCO.) The -o force enable operation clears the badlog flag on the DCO.
The following command sequence demonstrates how to recover the DCO volume that tracks the top-level volume vol1 in the disk group egdg:
vxdco -g egdg -o force enable vol1_dco vxvol -g egdg stop vol1 vxvol -g egdg start vol1
Here vol1_dco is the DCO associated with vol1.
Caution: Only use the -o force enable operation if you are certain that no writes have gone to the volume since the error occurred that caused its DCO volume to become detached. Otherwise, data corruption may result.
The -g diskgroup option specifies the disk group to which the parent volume, DCO object, and DCO volume belong.
You can use the make keyword to vxassist to create a volume with an attached DCO object and DCO volume. You can also use the addlog keyword to vxassist to create and add a DCO object and DCO volume to an existing volume. vxdco may then be used to dissociate a DCO object from its parent volume, and subsequently reattach it if the DCO object and DCO volume have not been removed.
The vxdco command is also used by vxassist and vxplex to handle the DCO objects and DCO volumes that are associated with volumes. The vxmake command is used to create DCO objects, which can be specified using output from vxprint.
Note: When using disk group move, split and join (see vxdg(1M)) to move volumes or snapshot volumes between disk groups, take care to ensure that the DCO volumes accompany their parent volumes.
See vxintro(1M) for a list of standard exit codes.
Last updated: 28 Jul 2003
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