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Increasing the size of an aggregate

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.

Before you begin

You must understand the following concepts:
  • The requirement to add disks or array LUNs owned by the same system and pool
  • For aggregates composed of disks:
    • Benefits of keeping your RAID groups homogeneous for disk size and speed.
    • Which types of disks can be used together.
    • Checksum rules when disks of more than one checksum type are in use.
    • How to ensure that the correct disks are added to the aggregate (the disk addition operation cannot be undone).
    • How to add disks to aggregates from heterogeneous storage.
    • The minimum number of disks to add for best performance.
    • The number of hot spares you need to provide for protection against disk failures.
    • Requirements for adding disks from multi-disk carrier disk shelves
    • The requirement to add storage to both plexes of a mirrored aggregate at the same time to ensure that the plexes are the same size and contain the same disk types

About this task

When you add HDDs to an aggregate, you should add a complete RAID group. For information about adding SSDs to a Flash Pool aggregate, see Technical Report 4070: NetApp Flash Pool Design and Implementation Guide.


  1. Verify that appropriate spare disks or array LUNs are available for you to add by entering the following command: aggr status -s
    For disks, make sure that enough of the spares listed are of the correct type, size, speed, and checksum type for the target RAID group in the aggregate to which you are adding the disks.
  2. Add the disks or array LUNs by entering the following command: aggr add aggr_name [-T] [-c] [-f] [-n] [-g {raid_group_name | new | all}] disk_list

    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 tier 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:

    • ndisks[@disk_size]
    • -d disk1 [disk2...]

    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.

  3. If the previous step was unsuccessful because you are adding disks to a 32-bit aggregate and the additional disks would cause its size to exceed 16 TB, complete the following steps to expand the aggregate to 64-bit:
    1. Repeat the aggr add command you entered before, with the -64bit-upgrade normal parameter added.
      For example, if you entered the aggr add 10@600G command, you would enter the following command: aggr add -64bit-upgrade normal 10@600G
      Data ONTAP checks each volume associated with the aggregate to ensure that it has enough free space to be expanded to 64-bit. If all of the volumes have enough free space, the disks are added and the aggregate is expanded to the 64-bit format. If any of the volumes are too full to be expanded, the command fails.
    2. If the previous command failed, run the command again, replacing the -64-bit-upgrade normal parameter with the -64-bit-upgrade check parameter. Follow the instructions in the output of that command.
    3. If you had to add more space to any volume, repeat the aggr add command again, this time with the -64bit-upgrade normal parameter.
    4. If you want to ensure that the disk usage quota accounting for this aggregate is exactly correct, reinitialize quotas on all of its volumes.
      If you do not reinitialize quotas, quotas on volumes associated with this aggregate will remain active, but the disk usage accounting will be slightly lower than the actual usage until the next time quotas are reinitialized.


The following command adds four 300-GB disks to the aggr1 aggregate:

aggr add aggr1 4@300G

The following command adds the disks 5a.17, 5a.19, 5a.20, and 5a.26 to the rg1 RAID group of the aggr2 aggregate:

aggr add aggr2 -g rg1 -d 5a.17 5a.19 5a.20 5a.26

The following command adds four disks to each plex of a mirrored aggregate aggr_mir:

aggr add aggr_mir -d 5a.18 5a.19 5a.20 5a.21 -d 8b.14 8b.15 8b.16 8b.17

After you finish

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.