Chapter 4. Hosting Virtual Machine Images on Red Hat Gluster Storage volumes

Red Hat Gluster Storage provides a POSIX-compatible file system to store virtual machine images in Red Hat Gluster Storage volumes.
This chapter describes how to configure volumes using the command line interface, and how to prepare Red Hat Gluster Storage servers for virtualization using Red Hat Virtualization Manager.

4.1. Configuring Volumes Using the Command Line Interface

Red Hat recommends configuring volumes before starting them. For information on creating volumes, see Red Hat Gluster Storage Volumes in the Red Hat Gluster Storage Administration Guide: https://access.redhat.com/documentation/en-us/red_hat_gluster_storage/3.4/html/administration_guide/chap-red_hat_storage_volumes.

Procedure 4.1. Configuring Volumes Using the Command Line Interface

  1. Configure the rhgs-random-io tuned profile

    Install the tuned tuning daemon and configure Red Hat Gluster Storage servers to use the rhgs-random-io profile:
    # yum install tuned
    # tuned-adm profile rhgs-random-io
    For more information on available tuning profiles, refer to the tuned-adm man page, or see the Red Hat Gluster Storage 3.4 Administration Guide: https://access.redhat.com/documentation/en-us/red_hat_gluster_storage/3.4/html/administration_guide/.

    Note

    When you upgrade, a new virt file may be created in /var/lib/glusterd/groups/virt.rpmnew. Apply the new virt file to the existing volumes by renaming the virt.rpmnew file to virt.
  2. Assign volumes to virt group

    Assign volumes that store virtual machine images to the virt volume group to apply the settings in the virt profile. This has the same effect as the Optimize for Virt Store option in the management console.
    # gluster volume set VOLNAME group virt
    See Appendix A, The virt group profile for more information about this configuration.

    Important

    Volumes in the virt group must only be used for storing machine images, and must only be accessed using the native FUSE client.
  3. (Recommended) Configure improved self-heal performance

    Run the following command to improve the performance of volume self-heal operations.
    # gluster volume heal volname cluster.granular-entry-heal enable
  4. Allow KVM and VDSM brick access

    Set the brick permissions for vdsm and kvm. If you do not set the required brick permissions, creation of virtual machines fails.
    1. Set the user and group permissions using the following commands:
      # gluster volume set VOLNAME storage.owner-uid 36
      # gluster volume set VOLNAME storage.owner-gid 36
    2. If you are using QEMU/KVM as a hypervisor, set the user and group permissions using the following commands:
      # gluster volume set VOLNAME storage.owner-uid 107
      # gluster volume set VOLNAME storage.owner-gid 107