Tuesday, September 22, 2009

what is aggregate in Netapp

What is aggregate:

An aggregate is a collection of one or two plexes, depending on whether you
want to take advantage of RAID-level mirroring

When you create an aggregate, Data ONTAP assigns data disks and parity disks
to RAID groups, depending on the options you choose, such as the size of the
RAID group

aggregates to manage plexes and RAID groups because these entities
only exist as part of an aggregate

You can increase the usable space in an
aggregate by adding disks to existing RAID groups or by adding new RAID
groups.

Once you’ve added disks to an aggregate, you cannot remove them to
reduce storage space without first destroying the aggregate

SyncMirror feature is licensed and enabled, you can convert an unmirrored
aggregate to a mirrored aggregate and vice versa without any downtime

Planning aggregate:

New storage system with Data ONTAP 7.0 or later installed, the root FlexVol (vol0) and its containing aggregate (aggr0) are already configured.

remaining disks on the storage system are all unallocated. You can create any
combination of aggregates with FlexVol volumes, traditional volumes, qtrees,
and LUNs, according to your needs

Maximizing storage:

configure large aggregates containing multiple FlexVol volumes.
Because multiple FlexVol volumes within the same aggregate share the same
RAID parity disk resources, more of your disks are available for data storage.

Size of RAID groups

When you create an aggregate, you can control the size
of a RAID group. Generally, larger RAID groups maximize your data storage
space by providing a greater ratio of data disks to parity disks

Types of RAID protection

Data ONTAP supports two types of RAID protection, which you can assign on a per-aggregate basis: RAID4 and RAID-DP.

How to Create Aggregate:


To check free resource

aggr status -s
-s displays a listing of the spare disks on the filer.

Create aggregate:


aggr create [ -m ] [-r raidsize] aggr ndisks[@disksize]

Example:
aggr create aggr1 24@72G

Result: An aggregate named aggr1 is created. It consists of 24 72-
GB disks.
-m instructs Data ONTAP to implement SyncMirror
-r raidsize specifies the maximum number of disks of each RAID
group in the aggregate.

For size in kilobytes, enter:
df -A aggr1

For size in 4096-byte blocks, enter:

aggr status -b aggr1

For size in number of disks, enter:

aggr status { -d | -r } aggr0
-d displays disk information
-r displays RAID information

To check status

Aggr status aggr1

Adding disk to Existing aggregate:


Adding disks to a specific RAID group in an aggregate

aggr add aggr_name -g raidgroup ndisks[@disk-size] | -d
disk-name...
EX:
aggr add aggr0 -g rg0 2

Display Disk space:

df -A aggr1

Destroying an aggregate

aggr offline aggr_name

aggr destroy aggr_name

Physically moving on aggregate:































ggregate:

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