Comparing the plexes of mirrored aggregate or traditional volumes

When you should compare plexes

Because the plexes of mirrored aggregate and traditional volumes are almost always synchronized, you rarely need to compare the plexes of a mirrored aggregate or traditional volume. If you do need to compare the plexes of a mirrored aggregate or traditional volume, Data ONTAP enables you to do the following tasks:

Compare plexes
Note
Comparing plexes might affect storage system performance.
Stop comparing plexes
Suspend and resume comparing plexes
View the progress of the comparison

Comparing plexes

The mirrored aggregate or traditional volume must be online before you can compare the plexes. When comparing the two plexes of a mirrored aggregate or traditional volume, you can choose one of the following options:

Data ONTAP compares plexes and corrects differences it finds.
Data ONTAP compares plexes without correcting differences. If you choose this option, you must determine which plex is the good one and synchronize the other plex to it. This process can be difficult and can use advanced Data ONTAP commands. Consult Technical Support before correcting differences using this option.

To compare the two plexes of a mirrored aggregate or traditional volume, complete the following step.

Step	Action
1	If you...	Then...
Want Data ONTAP to correct differences	Enter the following command: *{ aggr \| vol } verify start { aggrname* \| volname }** aggrname is the name of the mirrored aggregate whose plexes you are comparing. volname is the name of the mirrored volume whose plexes you are comparing. If neither aggrname nor volname is specified, the plexes of all online mirrored volumes are compared.
Do not want Data ONTAP to correct differences	Enter the following command: *{ aggr \| vol } verify start { aggrname* \| volname } -n** If neither aggrname nor volname is specified, Data ONTAP compares the plexes of a mirrored aggregate or traditional volume for all aggregates or traditional volumes.

Step

Action

If you...

Then...

Want Data ONTAP to correct differences

Enter the following command:

{ aggr | vol } verify start { 
aggrname | volname }

aggrname is the name of the mirrored aggregate whose plexes you are comparing. volname is the name of the mirrored volume whose plexes you are comparing. If neither aggrname nor volname is specified, the plexes of all online mirrored volumes are compared.

Do not want Data ONTAP to correct differences

Enter the following command:

{ aggr | vol } verify start { 
aggrname | volname } -n

If neither aggrname nor volname is specified, Data ONTAP compares the plexes of a mirrored aggregate or traditional volume for all aggregates or traditional volumes.

Stopping plex comparison

You might need to stop Data ONTAP from comparing mirrored aggregate or traditional volume plexes. For example, you might stop verifying because it affects storage system performance. To stop Data ONTAP from comparing plexes, complete the following step.

Step	Action
1	Enter the following command: *{ aggr \| vol } verify stop { aggrname* \| volname }** If aggrname or volname is not specified, Data ONTAP stops comparing plexes for all aggregates or traditional volumes.

Suspending and resuming plex comparison

Rather than stopping Data ONTAP from comparing the plexes of a mirrored aggregate or traditional volume, you can suspend the comparison of plexes. The comparison remains suspended until you resume it, stop it, or reboot the system.

To suspend or resume a comparison of plexes, complete the following step.

Step	Action
1	If you want to...	Then...
Suspend the comparison	Enter the following command: *{ aggr \| vol } verify suspend { aggrname* \| volname }** If aggrname or volname is not specified, Data ONTAP suspends the comparison of plexes for all aggregates or volumes.
Resume the comparison	Enter the following command: *{ aggr \| vol } vol verify resume { aggrname* \| volname }** If aggrname or volname is not specified, Data ONTAP resumes the comparison of plexes for all aggregates or volumes.

Step

Action

If you want to...

Then...

Suspend the comparison

Enter the following command:

{ aggr | vol } verify suspend 
{ aggrname | volname }

If aggrname or volname is not specified, Data ONTAP suspends the comparison of plexes for all aggregates or volumes.

Resume the comparison

Enter the following command:

{ aggr | vol } vol verify 
resume { aggrname | volname }

If aggrname or volname is not specified, Data ONTAP resumes the comparison of plexes for all aggregates or volumes.

Viewing the status of a plex comparison

Plex comparison status tells you what percentage of the plex comparison has been completed and whether plex comparison of a mirrored aggregate or traditional volume is suspended.

To view the status of a plex comparison, complete the following step.

Step	Action
1	Enter the following command: *{ aggr \| vol } verify status { aggrname* \| volname }** If aggrname or volname is not specified, Data ONTAP shows the status of all aggregates or volumes whose plexes are currently being compared.