Plex states reflect whether or not plexes are complete and are consistent copies (mirrors) of the volume contents. VxVM utilities automatically maintain the plex state. However, if a volume should not be written to because there are changes to that volume and if a plex is associated with that volume, you can modify the state of the plex. For example, if a disk with a particular plex located on it begins to fail, you can temporarily disable that plex.
A plex does not have to be associated with a volume. A plex can be created with the
plex command and be attached to a volume later.
VxVM utilities use plex states to:
This section explains the individual plex states in detail.
See the Veritas Volume Manager Troubleshooting Guide.
Plexes that are associated with a volume have one of the following plex states:
In the latter case, a system failure can leave plex contents in an inconsistent state. When a volume is started, VxVM does the recovery action to guarantee that the contents of the plexes marked as ACTIVE are made identical.
A plex is in a CLEAN state when it is known to contain a consistent copy (mirror) of the volume contents and an operation has disabled the volume. As a result, when all plexes of a volume are clean, no action is required to guarantee that the plexes are identical when that volume is started.
The IOFAIL plex state is associated with persistent state logging. When the
This state indicates that the plex is out-of-date with respect to the volume, and that it requires complete recovery. It is likely that one or more of the disks associated with the plex should be replaced.
This state indicates a snapshot plex that is being attached by the snapstart operation. When the attach is complete, the state for the plex is changed to SNAPDONE. If the system fails before the attach completes, the plex and all of its subdisks are removed.
This state indicates a snapshot plex that is fully attached. A plex in this state can be turned into a snapshot volume with the
If there is a possibility that a plex does not have the complete and current volume contents, that plex is placed in the STALE state. Also, if an I/O error occurs on a plex, the kernel stops using and updating the contents of that plex, and the plex state is set to STALE.
Setting a plex to the TEMP state eases some plex operations that cannot occur in a truly atomic fashion. For example, attaching a plex to an enabled volume requires copying volume contents to the plex before it can be considered fully attached.
A utility sets the plex state to TEMP at the start of such an operation and to an appropriate state at the end of the operation. If the system fails for any reason, a TEMP plex state indicates that the operation is incomplete. A later
A TEMPRM plex state is similar to a TEMP state except that at the completion of the operation, the TEMPRM plex is removed. Some subdisk operations require a temporary plex. Associating a subdisk with a plex, for example, requires updating the subdisk with the volume contents before actually associating the subdisk. This update requires associating the subdisk with a temporary plex, marked TEMPRM, until the operation completes and removes the TEMPRM plex.