Creating mirrored aggregates and traditional volumes

Two ways to create mirrored aggregates or traditional volumes

You can create a mirrored aggregate or traditional volume in 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.

How Data ONTAP selects disks

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.

Disk selection policies if you select disks

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. See the previous section, How Data ONTAP selects disks.

See Creating a mirrored aggregate or traditional volume and Adding a plex for information about creating mirrored aggregate or traditional volumes with disks you select.

Data ONTAP names plexes

Regardless of how a mirrored aggregate or traditional volume is created, Data ONTAP names the plexes of the mirrored aggregate or traditional volume. For more information about the plex naming convention, see What mirrored aggregates and traditional volumes are.

Viewing plex and disk pools

Viewing the disks in a plex or the spare disks in a disk pool is useful for adding disks to a plex or for understanding which plex is using which disk pool. To view plexes and disk pools, complete the following step.

Step	Action
1	Enter one of the following commands: sysconfig -r or aggr status -r or vol status -r

Example

In this example, the aggr status -r command is used to view the disks in plexes and spare disks in disk pools:

system1> aggr status -r

Aggregate vol0 (online, raid4) (block checksums)

Plex /vol0/plex0 (online, normal, active, pool1)

RAID group /vol0/plex0/rg0 (normal)



RAID Disk Device  HA  SHELF BAY CHAN Pool Type  RPM  Used (MB/blks) Ph)

--------- ------  ------------- ---- ---- ---- ----- --------------    ---

parity    9a.16   9a    1   0   FC:A   1  FCAL 10000 34000/69632000    34

data      9a.17   9a    1   1   FC:A   1  FCAL 10000 600/1228800       76

data      9a.20   9a    1   4   FC:A   1  FCAL 10000 34000/69632000    34



Aggregate GreG (online, raid4) (block checksums)

Plex /GreG/plex0 (online, normal, active, pool1)

RAID group /GreG/plex0/rg0 (normal)



RAID Disk Device  HA  SHELF BAY CHAN Pool Type  RPM  Used (MB/blks)    Ph)

--------- ------  ------------- ---- ---- ---- ----- --------------    ---

parity    9a.18   9a    1   2   FC:A   1  FCAL 10000 34000/69632000    34

data      9a.19   9a    1   3   FC:A   1  FCAL 10000 34000/69632000    34





Pool1 spare disks



RAID Disk       Device  HA  SHELF BAY CHAN Pool Type  RPM  Used (MB/blks)    Ph)

---------       ------  ------------- ---- ---- ---- ----- --------------    ---

Spare disks for block or zoned checksum traditional volumes or aggregates

spare           9a.24   9a    1   8   FC:A   1  FCAL 10000 34000/69632000    34

spare           9a.29   9a    1   13  FC:A   1  FCAL 10000 34000/69632000    34



Pool0 spare disks (empty)



Partner disks



RAID Disk       Device  HA  SHELF BAY CHAN Pool Type  RPM  Used (MB/blks)    Ph)

---------       ------  ------------- ---- ---- ---- ----- --------------    ---

partner         9b.25   9b    1   9   FC:B   1  FCAL 10000 0/0               34

partner         9b.16   9b    1   0   FC:B   1  FCAL 10000 0/0               34

partner         9b.17   9b    1   1   FC:B   1  FCAL 10000 0/0               34

partner         9b.21   9b    1   5   FC:B   1  FCAL 10000 0/0               34

partner         9b.18   9b    1   2   FC:B   1  FCAL 10000 0/0               34

partner         9b.22   9b    1   6   FC:B   1  FCAL 10000 0/0               34

tpubs-cf1>

Example

In this example, the vol status -r command is used to view the disks in plexes and spare disks in disk pools:

system1> vol status -r

Volume vol0 (online, raid4) (block checksums)

  Plex /vol0/plex0 (online, normal, active, pool1)

    RAID group /vol0/plex0/rg0 (normal)

      RAID Disk Device  HA  SHELF BAY CHAN Pool Type  RPM  Used (MB/blks)    Ph)

      --------- ------  ------------- ---- ---- ---- ----- --------------    ---

      parity    9a.16   9a    1   0   FC:A   1  FCAL 10000 34000/69632000    34

      data      9a.17   9a    1   1   FC:A   1  FCAL 10000 600/1228800       76

      data      9a.20   9a    1   4   FC:A   1  FCAL 10000 34000/69632000    34

Aggregate aggrz (online, raid4) (block checksums)

  Plex /aggrz/plex0 (online, normal, active, pool1)

    RAID group /aggrz/plex0/rg0 (normal)

      RAID Disk Device  HA  SHELF BAY CHAN Pool Type  RPM  Used (MB/blks)    Ph)

      --------- ------  ------------- ---- ---- ---- ----- --------------    ---

      parity    9a.25   9a    1   9   FC:A   1  FCAL 10000 34000/69632000    34

      data      9a.26   9a    1   10  FC:A   1  FCAL 10000 34000/69632000    34

      data      9a.27   9a    1   11  FC:A   1  FCAL 10000 34000/69632000    34

      data      9a.28   9a    1   12  FC:A   1  FCAL 10000 34000/69632000    34

Pool1 spare disks

RAID Disk       Device  HA  SHELF BAY CHAN Pool Type  RPM  Used (MB/blks)    Ph)

---------       ------  ------------- ---- ---- ---- ----- --------------    ---

Spare disks for block or zoned checksum traditional volumes or aggregates

spare           9a.24   9a    1   8   FC:A   1  FCAL 10000 34000/69632000    34

spare           9a.29   9a    1   13  FC:A   1  FCAL 10000 34000/69632000    34

Pool0 spare disks (empty)

Partner disks

RAID Disk       Device  HA  SHELF BAY CHAN Pool Type  RPM  Used (MB/blks)    Ph)

---------       ------  ------------- ---- ---- ---- ----- --------------    ---

partner         9b.25   9b    1   9   FC:B   1  FCAL 10000 0/0               34

partner         9b.16   9b    1   0   FC:B   1  FCAL 10000 0/0               34

partner         9b.17   9b    1   1   FC:B   1  FCAL 10000 0/0               34

partner         9b.21   9b    1   5   FC:B   1  FCAL 10000 0/0               34

partner         9b.18   9b    1   2   FC:B   1  FCAL 10000 0/0               34

partner         9b.22   9b    1   6   FC:B   1  FCAL 10000 0/0               34

partner         9b.23   9b    1   7   FC:B   1  FCAL 10000 0/0               34

For detailed information

The following sections discuss the ways you can create mirrored aggregate or traditional volumes: