I sometimes come across
situations where people don't know you can add
larger disks into an aggregate of smaller disks, and not
suffer the larger disks being right-sized down to keep inline with
the smaller disks. If you have larger disks to add to your system,
and you want to maintain a system with as few aggregates as possible
(or 1), the key is to use the
switch -raidgroup new
when adding the new disks to the aggregate.
In the below
walk-through we demonstrate this. I am using a NetApp ONTAP 9.7
simulator with 14 * 1GB disks and 14 * 4GB disks.
Note i: Good to know
that this 2013 blog post Clustered
ONTAP 8.2 SIM: Maximizing Available Usable Space still works to
some extent with the ONTAP 9.7 simulator.
Note ii: The
8 year old Home Lab lives on! ;-)
Walk-Through
These
5 bullet points cover the essence of what's happening in the
succeeding Clustershell output.
- Create a RAID-DP aggregate of 10 * 1GB disks and see it has usable space of 7.03GB.
- See the aggregate disks usable size is 1020MB (~1GB).
- See our 14 * 4GB spare disks have usable size 3.93GB.
- Simulate adding a new RAID-DP raidgroup of 12 * 4GB disks to our aggregate, and see each disk has usable size 3.91GB.
- After adding the 12 disks to our 10 disk 7.03GB aggregate, the aggregate now has a total size of 42GB.
CLU01::> aggr create -aggregate aggr1_CLU01_01 -diskcount 10 -node CLU01-01 -simulate
The layout for aggregate "aggr1_CLU01_01" on node "CLU01-01" would be:
First Plex
RAID Group rg0, 10 disks (block checksum, raid_dp)
Position Disk Size Size
---------- -------- -------- --------
dparity NET-1.18 - -
parity NET-1.19 - -
data NET-1.20 1000MB 1.00GB
data NET-1.21 1000MB 1.00GB
data NET-1.22 1000MB 1.00GB
data NET-1.23 1000MB 1.00GB
data NET-1.24 1000MB 1.00GB
data NET-1.25 1000MB 1.00GB
data NET-1.26 1000MB 1.00GB
data NET-1.27 1000MB 1.00GB
Aggregate capacity available for volume use would be 7.03GB.
CLU01::> aggr create -aggregate aggr1_CLU01_01 -diskcount 10 -node CLU01-01
CLU01::> disk show -container-name aggr1_CLU01_01 -fields usable-size,physical-size
disk physical usable
-size -size
-------- -------- ----------
NET-1.18 1.00GB 1020MB
NET-1.19 1.00GB 1020MB
NET-1.20 1.00GB 1020MB
NET-1.21 1.00GB 1020MB
NET-1.22 1.00GB 1020MB
NET-1.23 1.00GB 1020MB
NET-1.24 1.00GB 1020MB
NET-1.25 1.00GB 1020MB
NET-1.26 1.00GB 1020MB
NET-1.27 1.00GB 1020MB
10 entries were displayed.
CLU01::> disk show -usable-size 3.93G -fields usable-size,container-type
disk container usable
-type -size
-------- --------- ----------
NET-1.1 spare 3.93GB
NET-1.2 spare 3.93GB
NET-1.3 spare 3.93GB
NET-1.4 spare 3.93GB
NET-1.5 spare 3.93GB
NET-1.6 spare 3.93GB
NET-1.7 spare 3.93GB
NET-1.8 spare 3.93GB
NET-1.9 spare 3.93GB
NET-1.10 spare 3.93GB
NET-1.11 spare 3.93GB
NET-1.12 spare 3.93GB
NET-1.13 spare 3.93GB
NET-1.14 spare 3.93GB
CLU01::> aggr add-disks -aggregate aggr1_CLU01_01 -disksize 4 -diskcount 12 -raidgroup new -simulate true
Disks would be added to aggregate "aggr1_CLU01_01" on node "CLU01-01" in the following manner:
First Plex
RAID Group rg1, 12 disks (block checksum, raid_dp)
Position Disk Size Size
---------- -------- -------- --------
dparity NET-1.2 - -
parity NET-1.3 - -
data NET-1.4 3.91GB 3.93GB
data NET-1.5 3.91GB 3.93GB
data NET-1.6 3.91GB 3.93GB
data NET-1.7 3.91GB 3.93GB
data NET-1.8 3.91GB 3.93GB
data NET-1.9 3.91GB 3.93GB
data NET-1.10 3.91GB 3.93GB
data NET-1.11 3.91GB 3.93GB
data NET-1.12 3.91GB 3.93GB
data NET-1.13 3.91GB 3.93GB
Aggregate capacity available for volume use would be increased by 35.16GB.
CLU01::> aggr add-disks -aggregate aggr1_CLU01_01 -disksize 4 -diskcount 12 -raidgroup new
CLU01::*> df -A -aggregate aggr1_CLU01_01 -skip-snapshot-lines -gigabyte
Aggregate total used avail capacity
aggr1_CLU01_01 42GB 0GB 42GB 0%
Image: Adding 14 type 23 disks (1000MB) to the ONTAP VSIM
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