7.2. Native Client

Native Client is a FUSE-based client running in user space. Native Client is the recommended method for accessing Red Hat Storage volumes when high concurrency and high write performance is required.
This section introduces Native Client and explains how to install the software on client machines. This section also describes how to mount Red Hat Storage volumes on clients (both manually and automatically) and how to verify that the Red Hat Storage volume has mounted successfully.

Table 7.6. Red Hat Storage Server Support Matrix

Red Hat Enterprise Linux version Red Hat Storage Server version Native client version
6.5 3.0 3.0, 2.1*
6.6 3.0.2, 3.0.3, 3.0.4 3.0, 2.1*

Note

*If an existing Red Hat Storage 2.1 cluster is upgraded to Red Hat Storage 3.0, older 2.1 based clients can mount the new 3.0 volumes, however, clients must be upgraded to Red Hat Storage 3.0 to run rebalance. For more information, see Section 7.2.3, “Mounting Red Hat Storage Volumes”

7.2.1. Installing Native Client

After installing the client operating system, register the target system to Red Hat Network and subscribe to the Red Hat Enterprise Linux Server channel.

Important

All clients must be of the same version. Red Hat strongly recommends upgrading the servers before upgrading the clients.

Use the Command Line to Register, and Subscribe a System.

Register the system using the command line, and subscribe to the correct channels.

Prerequisites

  • Know the user name and password of the Red Hat Network (RHN) account with Red Hat Storage entitlements.
  1. Run the rhn_register command to register the system with Red Hat Network. 
    # rhn_register
  2. In the Operating System Release Version screen, select All available updates and follow the prompts to register the system to the standard base channel of the respective Red Hat Enterprise Linux Server version.
  3. Run the rhn-channel --add --channel command to subscribe the system to the correct Red Hat Storage Native Client channel:
    • For Red Hat Enterprise Linux 7.x clients using Red Hat Satellite Server: 
      # rhn-channel --add --channel= rhel-x86_64-server-rh-common-7
    • For Red Hat Enterprise Linux 6.x clients: 
      # rhn-channel --add --channel=rhel-x86_64-server-rhsclient-6
    • For Red Hat Enterprise Linux 5.x clients: 
      # rhn-channel --add --channel=rhel-x86_64-server-rhsclient-5
  4. Execute the following commands, for Red Hat Enterprise Linux clients using Subscription Manager.
    1. Run the following command and enter your Red Hat Network user name and password to register the system with the Red Hat Network. 
      # subscription-manager register --auto-attach
    2. Run the following command to enable the channels required to install Red Hat Storage Native Client:
      • For Red Hat Enterprise Linux 7.x clients: 
        # subscription-manager repos --enable=rhel-7-server-rpms --enable=rhel-7-server-rh-common-rpms
      • For Red Hat Enterprise Linux 6.1 and later clients: 
        # subscription-manager repos --enable=rhel-6-server-rpms --enable=rhel-6-server-rhs-client-1-rpms
      • For Red Hat Enterprise Linux 5.7 and later clients: 
        # subscription-manager repos --enable=rhel-5-server-rpms --enable=rhel-5-server-rhs-client-1-rpms
      For more information, see Section 3.2 Registering from the Command Line in the Red Hat Subscription Management guide.
  5. Run the following command to verify if the system is subscribed to the required channels. 
    # # yum repolist

Use the Web Interface to Register, and Subscribe a System.

Register the system using the web interface, and subscribe to the correct channels.

Prerequisites

  • Know the user name and password of the Red Hat Network (RHN) account with Red Hat Storage entitlements.
  1. Log on to Red Hat Network (http://rhn.redhat.com).
  2. Move the mouse cursor over the Subscriptions link at the top of the screen, and then click the Registered Systems link.
  3. Click the name of the system to which the Red Hat Storage Native Client channel must be appended.
  4. Click Alter Channel Subscriptions in the Subscribed Channels section of the screen.
  5. Expand the node for Additional Services Channels for Red Hat Enterprise Linux 6 for x86_64 or for Red Hat Enterprise Linux 5 for x86_64 depending on the client platform.
  6. Click the Change Subscriptions button to finalize the changes.
    When the page refreshes, select the Details tab to verify the system is subscribed to the appropriate channels.

Install Native Client Packages

Install Native Client packages from Red Hat Network
  1. Run the yum install command to install the native client RPM packages. 
    # yum install glusterfs glusterfs-fuse
  2. For Red Hat Enterprise 5.x client systems, run the modprobe command to load FUSE modules before mounting Red Hat Storage volumes. 
    # modprobe fuse
    For more information on loading modules at boot time, see https://access.redhat.com/knowledge/solutions/47028 .

7.2.2. Upgrading Native Client

Before updating the Native Client, subscribe the clients to the channels mentioned in Use the Command Line to Register, and Subscribe a System.
Run the yum update command to upgrade the native client: 
# yum update glusterfs glusterfs-fuse

7.2.3. Mounting Red Hat Storage Volumes

After installing Native Client, the Red Hat Storage volumes must be mounted to access data. Two methods are available:
After mounting a volume, test the mounted volume using the procedure described in Section 7.2.3.4, “Testing Mounted Volumes”.

Note

  • When a new volume is created in Red Hat Storage 3.0, it cannot be accessed by an older (Red Hat Storage 2.1.x) clients, because the readdir-ahead translator is enabled by default for the newly created Red Hat Storage 3.0 volumes. This makes it incompatible with older clients. In order to resolve this issue, disable readdir-ahead in the newly created volume using the following command: 
    # gluster volume set VOLNAME readdir-ahead off
  • Server names selected during volume creation should be resolvable in the client machine. Use appropriate /etc/hosts entries, or a DNS server to resolve server names to IP addresses.

7.2.3.1. Mount Commands and Options

The following options are available when using the mount -t glusterfs command. All options must be separated with commas. 
# mount -t glusterfs -o backup-volfile-servers=volfile_server2:volfile_server3:.... ..:volfile_serverN,transport-type tcp,log-level=WARNING,log-file=/var/log/gluster.log server1:/test-volume /mnt/glusterfs
backup-volfile-servers=<volfile_server2>:<volfile_server3>:...:<volfile_serverN>
List of the backup volfile servers to mount the client. If this option is specified while mounting the fuse client, when the first volfile server fails, the servers specified in backup-volfile-servers option are used as volfile servers to mount the client until the mount is successful.

Note

This option was earlier specified as backupvolfile-server which is no longer valid.
log-level
Logs only specified level or higher severity messages in the log-file.
log-file
Logs the messages in the specified file.
transport-type
Specifies the transport type that FUSE client must use to communicate with bricks. If the volume was created with only one transport type, then that becomes the default when no value is specified. In case of tcp,rdma volume, tcp is the default.
ro
Mounts the file system as read only.
acl
Enables POSIX Access Control List on mount.
background-qlen=n
Enables FUSE to handle n number of requests to be queued before subsequent requests are denied. Default value of n is 64.
enable-ino32
this option enables file system to present 32-bit inodes instead of 64- bit inodes.

7.2.3.2. Mounting Volumes Manually

Manually Mount a Red Hat Storage Volume

Create a mount point and run the mount -t glusterfs HOSTNAME|IPADDRESS:/VOLNAME /MOUNTDIR command to manually mount a Red Hat Storage volume.

Note

The server specified in the mount command is used to fetch the glusterFS configuration volfile, which describes the volume name. The client then communicates directly with the servers mentioned in the volfile (which may not actually include the server used for mount).
  1. If a mount point has not yet been created for the volume, run the mkdir command to create a mount point. 
    # mkdir /mnt/glusterfs
  2. Run the mount -t glusterfs command, using the key in the task summary as a guide. 
    # mount -t glusterfs server1:/test-volume /mnt/glusterfs

7.2.3.3. Mounting Volumes Automatically

Volumes can be mounted automatically each time the systems starts.
The server specified in the mount command is used to fetch the glusterFS configuration volfile, which describes the volume name. The client then communicates directly with the servers mentioned in the volfile (which may not actually include the server used for mount).
Mounting a Volume Automatically
Mount a Red Hat Storage Volume automatically at server start.
  1. Open the /etc/fstab file in a text editor.
  2. Append the following configuration to the fstab file. 
    HOSTNAME|IPADDRESS:/VOLNAME /MOUNTDIR glusterfs defaults,_netdev 0 0
    Using the example server names, the entry contains the following replaced values. 
    server1:/test-volume /mnt/glusterfs glusterfs defaults,_netdev 0 0
    If you want to specify the transport type then check the following example: 
    server1:/test-volume /mnt/glusterfs glusterfs defaults,_netdev,transport=tcp 0 0

7.2.3.4. Testing Mounted Volumes

Testing Mounted Red Hat Storage Volumes

Using the command-line, verify the Red Hat Storage volumes have been successfully mounted. All three commands can be run in the order listed, or used independently to verify a volume has been successfully mounted.
  1. Run the mount command to check whether the volume was successfully mounted. 
    # mount
server1:/test-volume on /mnt/glusterfs type fuse.glusterfs(rw,allow_other,default_permissions,max_read=131072
    If transport option is used while mounting a volume, mount status will have the transport type appended to the volume name. For example, for transport=tcp: 
    # mount
server1:/test-volume.tcp on /mnt/glusterfs type fuse.glusterfs(rw,allow_other,default_permissions,max_read=131072
  2. Run the df command to display the aggregated storage space from all the bricks in a volume. 
    # df -h /mnt/glusterfs 
Filesystem           Size  Used  Avail  Use%  Mounted on
server1:/test-volume  28T  22T   5.4T   82%   /mnt/glusterfs
  3. Move to the mount directory using the cd command, and list the contents. 
    # cd /mnt/glusterfs 
# ls