Ceph

Please add this to the page:

http://ceph.com/docs/master/rbd/qemu-rbd/#enabling-discard-trim

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If using libvirt, edit your libvirt domain's 'XML' file to include the xmlns:qemu value, then add a qemu:commandline block as a child of that domain. This example shows how to set two devices with qemu id= to different discard_granularity values.

<domain type='kvm' xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0&#039;>
<qemu:commandline>
<qemu:arg value='-set'/>
<qemu:arg value='block.scsi0-0-0.discard_granularity=4096'/>
<qemu:arg value='-set'/>
<qemu:arg value='block.scsi0-0-1.discard_granularity=65536'/>
</qemu:commandline>
</domain>