# Using auto capacity expansion
The auto expansion service ensures applications are not stopped because they ran out of space on a volume. While the CIO software provide notification events at 70, 80 and 90% volume capacity full, an operator must still respond and issue the commands to resize a volume.
With the auto expansion service, when a pre-defined capacity threshold is crossed, the volume is automatically increased at both the block and file system level. The capacity expansion happens while the application is online, which means there is no disruption to the application.
Create auto expand volume from CLI
Enable auto expansion for a volume by using the
--autoexpand flag during volume creation. Specify the threshold percentage when expansion will be triggered, the percentage capacity to increase, and how many times a volume is allowed to be expanded, e.g.
$ cio volume create auto --capacity 2 --autoexpand yes --threshold 70 --increment 25 --limit 3 Succeed: Add vd2: Type:2-copy, Size:2GB
Create auto expand volume from profile
You can also use a profile to set the auto expansion parameters for creating a volume. The example below enables auto expansion, sets expansion to trigger at 70% capacity threshold, increases capacity by 25% each time, and caps the number of expansions to 3:
capacity: 2 directory: /cio/auto iops: min: 100 max: 2000 level: 2 local: no provision: thin type: ssd service: autoexpand: enabled: yes threshold: 70 increment: 25 limit: 3 compression: enabled: no algorithm: lzo encryption: enabled: no replication: enabled: no destination: none interval: 120
Save the profile as AUTO with
cio profile create AUTO.
Create a volume with profile AUTO by running
cio volume create auto -p AUTO.
Confirm the auto expansion parameters with:
$ cio volume info auto vdisk 2 uuid 6fb5f248 node c3 ipaddr 192.168.3.142 nodeid 25c1cec6 name auto capacity 2GB redundancy 2 drive type SSD local drive only no provisioning thin minimum iops 100 maximum iops 2000 directory /cio/auto/vd2 autoexpand enabled yes autoexpand threshold 70 autoexpand increment 25 autoexpand limit 3 autoexpand count 0 encryption disabled snapshot disabled snapshot interval 60 maximum snapshots 10 filesystem xfs labels allocated 3.9%
Update auto expansion service
Once the limit for the number of automatic capacity expansions is reached, the autoexpand service will be disabled. You can re-enable the auto expansion service for a volume with:
cio volume update VOLUMENAME --autoexpand yes
With the auto expansion service, there are no more worries about individual applications running out of space. Life is much easier because you only need to monitor the capacity of the storage pool.