Configure and use volume number weigher¶
OpenStack Block Storage enables you to choose a volume back end according
to free_capacity and allocated_capacity. The volume number weigher
feature lets the scheduler choose a volume back end based on its volume
number in the volume back end. This can provide another means to improve
the volume back ends’ I/O balance and the volumes’ I/O performance.
Enable volume number weigher¶
To enable a volume number weigher, set the
scheduler_default_weighers to VolumeNumberWeigher flag in the
cinder.conf file to define VolumeNumberWeigher
as the selected weigher.
Configure multiple-storage back ends¶
To configure VolumeNumberWeigher, use LVMVolumeDriver
as the volume driver.
This configuration defines two LVM volume groups: stack-volumes with
10 GB capacity and stack-volumes-1 with 60 GB capacity.
This example configuration defines two back ends:
scheduler_default_weighers=VolumeNumberWeigher
enabled_backends=lvmdriver-1,lvmdriver-2
[lvmdriver-1]
volume_group=stack-volumes
volume_driver=cinder.volume.drivers.lvm.LVMVolumeDriver
volume_backend_name=LVM
[lvmdriver-2]
volume_group=stack-volumes-1
volume_driver=cinder.volume.drivers.lvm.LVMVolumeDriver
volume_backend_name=LVM
Volume type¶
Define a volume type in Block Storage:
$ openstack volume type create lvm
Create an extra specification that links the volume type to a back-end name:
$ openstack volume type set lvm --property volume_backend_name=LVM
This example creates a lvm volume type with
volume_backend_name=LVM as extra specifications.
Usage¶
To create six 1-GB volumes, run the openstack volume create --size 1 --type lvm volume1 command six times:
$ openstack volume create --size 1 --type lvm volume1
This command creates three volumes in stack-volumes and
three volumes in stack-volumes-1.
List the available volumes:
# lvs
LV VG Attr LSize Pool Origin Data% Move Log Copy% Convert
volume-3814f055-5294-4796-b5e6-1b7816806e5d stack-volumes -wi-a---- 1.00g
volume-72cf5e79-99d2-4d23-b84e-1c35d3a293be stack-volumes -wi-a---- 1.00g
volume-96832554-0273-4e9d-902b-ad421dfb39d1 stack-volumes -wi-a---- 1.00g
volume-169386ef-3d3e-4a90-8439-58ceb46889d9 stack-volumes-1 -wi-a---- 1.00g
volume-460b0bbb-d8a0-4bc3-9882-a129a5fe8652 stack-volumes-1 -wi-a---- 1.00g
volume-9a08413b-0dbc-47c9-afb8-41032ab05a41 stack-volumes-1 -wi-a---- 1.00g
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