Jay S. Bryant e9857d616d Migrate the blockstorage admin-guide to Cinder

This patch is part of the docs migration for Cinder.
It is more or less a drag and drop of the docs from
openstack-manuals admin-guide directory.  I needed to
change some syntax to work with Cinder's more stringent
doc build.

Note that the purpose of this patch is just to get the
documentation back to an accessible location.  Later patches
will clean up the organization and content.

Change-Id: Ib3f9255e0f9f2ff42a0ee4126607ff319a3d901e

2017-07-08 12:44:49 -05:00

2.8 KiB

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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

2.8 KiB Raw Blame History