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8.3. Preparing and Adding Local Storage

8.3.1. Preparing Local Storage

A local storage domain can be set up on a host. When you set up a host to use local storage, the host automatically gets added to a new data center and cluster that no other hosts can be added to. Multiple host clusters require that all hosts have access to all storage domains, which is not possible with local storage. Virtual machines created in a single host cluster cannot be migrated, fenced or scheduled. For more information on the required system users and groups see Appendix F, System Accounts.

Note

For information on preserving local storage domains when reinstalling Red Hat Virtualization Host (RHVH), see Upgrading to RHVH While Preserving Local Storage in the Upgrade Guide for Red Hat Virtualization 4.0 for more details.

Important

On Red Hat Virtualization Host (RHVH), local storage should always be defined on a file system that is separate from / (root). Red Hat recommends using a separate logical volume or disk, to prevent possible loss of data during upgrades.

Preparing Local Storage for Red Hat Enterprise Linux Hosts

  1. On the host, create the directory to be used for the local storage:

    # mkdir -p /data/images
  2. Ensure that the directory has permissions allowing read/write access to the vdsm user (UID 36) and kvm group (GID 36):

    # chown 36:36 /data /data/images
    # chmod 0755 /data /data/images

    Your local storage is ready to be added to the Red Hat Virtualization environment.

Preparing Local Storage for Red Hat Virtualization Hosts

Red Hat recommends creating the local storage on a logical volume as follows:

# mkdir /data
# lvcreate -L $SIZE rhvh -n data
# mkfs.ext4 /dev/mapper/rhvh-data
# echo "/dev/mapper/rhvh-data /data ext4 defaults,discard 1 2" >> /etc/fstab

Your local storage is ready to be added to the Red Hat Virtualization environment.

8.3.2. Adding Local Storage

Adding local storage to a host in this manner causes the host to be put in a new data center and cluster. The local storage configuration window combines the creation of a data center, a cluster, and storage into a single process.

Adding Local Storage

  1. Click ComputeHosts and select the host.
  2. Click ManagementMaintenance and click OK.
  3. Click ManagementConfigure Local Storage.
  4. Click the Edit buttons next to the Data Center, Cluster, and Storage fields to configure and name the local storage domain.
  5. Set the path to your local storage in the text entry field.
  6. If applicable, click the Optimization tab to configure the memory optimization policy for the new local storage cluster.
  7. Click OK.

Your host comes online in a data center of its own.