From: Sébastien Han Date: Mon, 10 Nov 2014 14:06:20 +0000 (+0100) Subject: doc: enable RBD cache and socket on OpenStack deployments X-Git-Tag: v0.90~103^2 X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=40994c918adf733bc907cb5d398c94e2e932afef;p=ceph.git doc: enable RBD cache and socket on OpenStack deployments Enabling the RBD cache improves sequential IOs and the socket helps a lot while troubleshooting. These 2 items are considered as best practice for OpenStack deployments with Ceph. Signed-off-by: Sébastien Han --- diff --git a/doc/rbd/rbd-openstack.rst b/doc/rbd/rbd-openstack.rst index 885e4469fa73..10d1d9af144c 100644 --- a/doc/rbd/rbd-openstack.rst +++ b/doc/rbd/rbd-openstack.rst @@ -263,6 +263,25 @@ Configuring Nova In order to boot all the virtual machines directly into Ceph, you must configure the ephemeral backend for Nova. +It is recommended to enable the RBD cache in your Ceph configuration file +(enabled by default since Giant). Moreover, enabling the admin socket +brings a lot of benefits while troubleshoothing. Having one socket +per virtual machine using a Ceph block device will help investigating performance and/or wrong behaviors. + +This socket can be accessed like this:: + + ceph daemon /var/run/ceph/ceph-client.cinder.19195.32310016.asok help + +Now on every compute nodes edit your Ceph configuration file:: + + [client] + rbd cache = true + rbd cache writethrough until flush = true + admin socket = /var/run/ceph/$cluster-$type.$id.$pid.$cctid.asok + +.. tip:: If your virtual machine is already running you can simply restart it to get the socket + + Havana and Icehouse ~~~~~~~~~~~~~~~~~~~ @@ -295,13 +314,13 @@ On every Compute node, edit ``/etc/nova/nova.conf`` and add:: To ensure a proper live-migration, use the following flags:: libvirt_live_migration_flag="VIR_MIGRATE_UNDEFINE_SOURCE,VIR_MIGRATE_PEER2PEER,VIR_MIGRATE_LIVE,VIR_MIGRATE_PERSIST_DEST" - - + + Juno ~~~~ -In Juno, Ceph block device was moved under the ``[libvirt]`` section. -On every Compute node, edit ``/etc/nova/nova.conf`` under the ``[libvirt]`` +In Juno, Ceph block device was moved under the ``[libvirt]`` section. +On every Compute node, edit ``/etc/nova/nova.conf`` under the ``[libvirt]`` section and add:: [libvirt]