You can create a mirrored aggregate or traditional volume using one of the following ways.
- You can create a new aggregate or traditional volume that has two plexes.
- You can add a plex to an existing unmirrored aggregate or traditional volume.
Note: A mirrored aggregate or traditional volume cannot have more than two plexes.
Regardless of which way you create a mirrored aggregate or traditional volume, when you create it or add disks to it,
Data ONTAP determines what disks to use.
Data ONTAP uses the following policies when selecting disks for mirrored aggregate or traditional volumes.
- Disks selected for each plex come from different disk pools.
- The number of disks selected for one plex must equal the number of disks selected for the other plex.
- Disks are selected first on the basis of equivalent bytes per sector (bps) size, then on the basis of the size of the disk.
- If there is no equivalent-sized disk, Data ONTAP takes a larger-capacity disk and downsizes it.
Note: When creating an unmirrored volume, Data ONTAP selects disks from the plex which has the most available disks. You can override this selection policy by specifying the disks to use.
Data ONTAP allows you to select disks when creating mirrored aggregate or traditional volumes or adding disks to them. You need to follow the same disk selection policies that Data ONTAP follows when selecting disks for mirrored aggregate or traditional volumes.
Regardless of how a mirrored aggregate or traditional volume is created, Data ONTAP names the plexes of the mirrored aggregate or traditional volume.
