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F.2. Configuring HA-LVM Failover with Tagging

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To set up HA-LVM failover by using tags in the /etc/lvm/lvm.conf file, perform the following steps:
  1. In the global section of the /etc/lvm/lvm.conf file, ensure that the locking_type parameter is set to the value '1' and the use_lvmetad parameter is set to the value '0'.

    Note

    As of Red Hat Enterprise Linux 6.7, you can use the --enable-halvm option of the lvmconf to set the locking type to 1 and disable lvmetad. For information on the lvmconf command, see the lvmconf man page.
  2. Create the logical volume and file system using standard LVM and file system commands, as in the following example. 
    # pvcreate /dev/sd[cde]1

# vgcreate shared_vg /dev/sd[cde]1

# lvcreate -L 10G -n ha_lv shared_vg

# mkfs.ext4 /dev/shared_vg/ha_lv
    For information on creating LVM logical volumes, refer to Logical Volume Manager Administration.
  3. Edit the /etc/cluster/cluster.conf file to include the newly created logical volume as a resource in one of your services. Alternately, you can use Conga or the ccs command to configure LVM and file system resources for the cluster. The following is a sample resource manager section from the /etc/cluster/cluster.conf file 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>

    Note

    If there are multiple logical volumes in the volume group, then the logical volume name (lv_name) in the lvm resource 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.
  4. Edit the volume_list field in the /etc/lvm/lvm.conf file. Include the name of your root volume group and your host name as listed in the /etc/cluster/cluster.conf file preceded by @. The host name to include here is the machine on which you are editing the lvm.conf file, not any remote host name. Note that this string MUST match the node name given in the cluster.conf file. Below is a sample entry from the /etc/lvm/lvm.conf file: 
    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.
  5. Update the initramfs device on all your cluster nodes: 
    # dracut -H -f /boot/initramfs-$(uname -r).img $(uname -r)
  6. Reboot all nodes to ensure the correct initramfs image is in use.
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