4.1. Accessing Virtuozzo Storage Clusters via NFS

To access a Virtuozzo Storage Cluster via NFS, you need to:

  1. Create and mount a ploop with the ext4 file system.
  2. Set up an NFS share using either the standard exportfs command or the /etc/exports file.
  3. Access the NFS share on the remote computer.

The following sections describe these steps in detail.

4.1.1. Preparing the Ploop

Loopback block devices (ploops) allow you to attach any Virtuozzo Storage file as a block device and format it to a conventional file system like ext4. Since Virtuozzo Storage is not optimized for small files and does not use a POSIX-compliant file system, you can use ploops with ext4 when you need the aforementioned functionality.

To prepare the ploop, do the following:

  1. Load the required modules:

    # modprobe ploop pfmt_ploop1 pio_kaio
    
  2. Create the ploop:

    # mkdir /vstorage/ploop0
    # ploop init -s 1g -t ext4 /vstorage/ploop0/img0
    

    This command creates a 1 GB ploop with the ext4 file system.

  3. Mount the ploop:

    # mkdir /mnt/ploop0
    # ploop mount -m /mnt/ploop0 /vstorage/ploop0/DiskDescriptor.xml
    
  4. (Optional) Set up a permanent ploop mount using /etc/fstab:

    # cat >> /etc/fstab <<EOF
    /vstorage/ploop0/DiskDescriptor.xml        /mnt/ploop0     ploop           defaults 0 0
    EOF
    

4.1.2. Setting Up the NFS Share

For the purpose of this example, let us assume that:

  1. The source computer IP address is 192.168.0.1 and the destination computer IP address is 192.168.0.2.
  2. The exportfs command is used to set up the NFS share
  3. On the destination computer, the NFS share is mounted to the /nfsshare directory.

To share the created file system via NFS, do the following:

  1. On the source computer, make sure the nfsd service is running.

  2. On the source computer, run the exportfs command as follows:

    # exportfs 192.168.0.2:/mnt/ploop0
    
  3. On the remote computer, mount the shared path as follows:

    # mount 192.168.0.1:/mnt/ploop0 /nfsshare
    

Now you can access the contents of the shared ext4 file system on the remote computer.

Note

More details on setting up NFS shares are provided in the Red Hat Enterprise Linux Storage Administration Guide.