You can add disks or array LUNs to an aggregate so that it can provide more storage to its associated volumes. If you need to add enough storage to a 32-bit aggregate to increase its size beyond 16 TB, you can do so; this operation expands the aggregate to 64-bit format.
Following these best practices when you add storage to an aggregate optimizes aggregate performance:
The new RAID group does not have to be exactly the same size as the existing RAID groups, but it should not be less than one half the size of the existing RAID groups.
Doing so results in the added disks being the target for a disproportionate percentage of new data, causing the new disks to become a performance bottleneck.
For information about adding SSDs to a Flash Pool aggregate, see Technical Report 4070: NetApp Flash Pool Design and Implementation Guide.
If you are adding disks with a different checksum than the aggregate, as when creating a Flash Pool aggregate, or if you are adding disks to a mixed checksum aggregate, you must either specify the disks to be added with a disk list or use the -c option to specify the checksum.
If you are adding disks to a Flash Pool aggregate, you must either specify the disks to be added with a disk list or use the -T option to specify the disk type.
-f enables you to add disks or array LUNs from a different pool or, for disks, of a different speed.
-n displays the results of the command but does not execute it. This is useful for displaying the disks or array LUNs that Data ONTAP would automatically select. You can then decide whether to accept the selection provided by Data ONTAP or to add different disks or array LUNs.
If you specify the -g option, the storage is added to the RAID group you specify. raid_group_name is the name that Data ONTAP gave to the group—for example, rg0. If you are adding SSDs to the SSD cache of a Flash Pool aggregate, you do not need to specify the RAID group name; the SSD RAID group is selected by default based on the type of the disks you are adding. You should always fill up the existing SSD RAID group before creating a new one.
To add the storage to a new RAID group, use the new value instead of the group name.
To fill all existing RAID groups to the current value of the raidsize option before creating a new RAID group, use the all keyword instead of the group name. When you specify the all keyword, Data ONTAP adds disks to an existing RAID group until it reaches the maximum size, and then moves on to the next existing RAID group. If there are more disks to be added and all existing RAID groups are full, Data ONTAP creates a new RAID group.
disk_list is one of the following parameters:
The disk_size parameter is the approximate size of the disk in GB. Disks that are within approximately 20 percent of the specified size are selected.
After you add storage to an aggregate, you should run a full reallocation job on each FlexVol volume contained in that aggregate. For information about reallocation, see the Data ONTAP System Administration Guide for 7-Mode.