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F.2. Configuring HA-LVM Failover with Tagging
To set up HA-LVM failover by using tags in the
/etc/lvm/lvm.conffile, perform the following steps:
- In the global section of the
/etc/lvm/lvm.conffile, ensure that the
locking_typeparameter is set to the value '1' and the
use_lvmetadparameter is set to the value '0'.
NoteAs of Red Hat Enterprise Linux 6.7, you can use the
--enable-halvmoption of the
lvmconfto set the locking type to 1 and disable
lvmetad. For information on the
lvmconfcommand, see the
- Create the logical volume and file system using standard LVM and file system commands, as in the following example.
vgcreate shared_vg /dev/sd[cde]1#
lvcreate -L 10G -n ha_lv shared_vg#
mkfs.ext4 /dev/shared_vg/ha_lvFor information on creating LVM logical volumes, refer to Logical Volume Manager Administration.
- Edit the
/etc/cluster/cluster.conffile to include the newly created logical volume as a resource in one of your services. Alternately, you can use Conga or the
ccscommand to configure LVM and file system resources for the cluster. The following is a sample resource manager section from the
/etc/cluster/cluster.conffile that configures a CLVM logical volume as a cluster resource:
<rm> <failoverdomains> <failoverdomain name="FD" ordered="1" restricted="0"> <failoverdomainnode name="neo-01" priority="1"/> <failoverdomainnode name="neo-02" priority="2"/> </failoverdomain> </failoverdomains> <resources> <lvm name="lvm" vg_name="shared_vg" lv_name="ha_lv"/> <fs name="FS" device="/dev/shared_vg/ha_lv" force_fsck="0" force_unmount="1" fsid="64050" fstype="ext4" mountpoint="/mnt" options="" self_fence="0"/> </resources> <service autostart="1" domain="FD" name="serv" recovery="relocate"> <lvm ref="lvm"/> <fs ref="FS"/> </service> </rm>
NoteIf there are multiple logical volumes in the volume group, then the logical volume name (
lv_name) in the
lvmresource should be left blank or unspecified. Also note that in an HA-LVM configuration, a volume group may be used by only a single service.
- Edit the
volume_listfield in the
/etc/lvm/lvm.conffile. Include the name of your root volume group and your host name as listed in the
/etc/cluster/cluster.conffile preceded by @. The host name to include here is the machine on which you are editing the
lvm.conffile, not any remote host name. Note that this string MUST match the node name given in the
cluster.conffile. Below is a sample entry from the
volume_list = [ "VolGroup00", "@neo-01" ]This tag will be used to activate shared VGs or LVs. DO NOT include the names of any volume groups that are to be shared using HA-LVM.
- Update the
initramfsdevice on all your cluster nodes:
dracut -H -f /boot/initramfs-$(uname -r).img $(uname -r)
- Reboot all nodes to ensure the correct
initramfsimage is in use.