Attach Storage Volumes operation

Use the Attach Storage Volumes operation to attach selected volumes to all IBM Storage Scale Servers in the cluster, and configure the IBM Storage Scale file system.

Before you begin

Review the following information before you attempt to attach a storage volume:
  • You can attach a maximum of 14 storage volumes to a IBM Storage Scale server deployment instance.
  • A file system includes 1 or more volumes, resulting in a maximum of 14 file systems.
  • If you deploy a one-node IBM Storage Scale configuration, you can attach block volumes only. If you deploy a three-, five-, or seven-node IBM Storage Scale configuration, you can attach block shared volumes only. You need to use block shared volumes when you deploy more than one IBM Storage Scale node since the volumes must be shared by all IBM Storage Scale server nodes in that deployment. Only valid volume types are available for selection in the Shared Volumes field. For example, if the current instance is a one-node IBM Storage Scale configuration, the Shared Volumes field displays block volumes only, which are not attached to other deployments. If the current instance is a multi-node IBM Storage Scale configuration, the Shared Volumes field displays block shared volumes only, which are not attached to other deployments.
  • The attached volumes must be at least 2 GB. Because IBM Storage Scale holds data and metadata on each volume, it cannot partition the disk if the size is less than 2 GB.
  • The tiebreaker volume (one per file system) can be 1 GB since it contains only IBM Storage Scale metadata. To ensure better IBM Storage Scale performance, the other volumes (attached to the primary, mirror, or passive instances), must have a volume of 10 GB or more.
  • For best IBM Storage Scale performance, use the same size for the volumes attached to the same file system.
  • The maximum allowed size of the volumes that are attached to the file system after the file system creation depends on the size of the volumes that are used at the file system's initial creation. For more information, see Adding disks to a file system. The maximum size of any one disk that can be added is set approximately to the sum of the disk sizes when the file system is created. Plan ahead and make sure that the size of the initial volumes that are used at file system creation is large enough to allow a volume size that you expect to use later.

About this task

You typically use this operation to attach volumes to one or more of your IBM Storage Scale Primary, Mirror, Tiebreaker, and Passive configuration instances.
Note: Do not run the Attach Storage Volumes operation at the same time on multiple instances in the cluster.

The order in which you attach volumes to the various instances in your cluster depends on the type of IBM Storage Scale environment and whether you are attaching volumes to new or existing file systems.

For example, when you attach new volumes to an existing file system in a deployed active-active configuration, always perform the operation on the Primary instance last.

For an active-active configuration with Primary, Mirror, and Tiebreaker instances, run the Attach Storage Volumes operation on the instances in the following order:
  1. Attach volumes to the Mirror configuration instance, and wait for completion.
  2. Attach a volume to the Tiebreaker configuration instance, and wait for completion.
  3. Attach volumes (of the same number and size as you attached to the Mirror instance) to the Primary configuration instance, and wait for completion.

You must always follow this attach order so that the file system is available on the Mirror instance for data replication as soon as a client writes content to the file system.

Alternatively, when you attach volumes to a new file system, always perform the operation on the Primary instance first, especially in an active-active configuration. New file systems can be created only from the IBM Storage Scale Primary instance.

As you attach volumes to new or existing file systems in your instances, keep in mind the following considerations:
  • If you are attaching the volume to a new file system (you select the Create new file system check box):
    1. Attach a volume to the Primary instance first. Be sure to select the Create new file system check box.
    2. For an active-active configuration:
      1. Attach a volume to the Mirror instance, of the same size and for the same file system that you attached to the Primary instance.
        Note:
        • Do not select the Create new file system check box. The file system already exists, because it was created by the Primary instance and is now mounted to the Mirror instance.
        • Ensure that you attach the volumes to the file system on the Mirror instance immediately after the Primary instance creates the file system. Otherwise, if the Primary instance goes down and the Mirror instance must take over, this file system will be unavailable.
      2. Because the tiebreaker disk is used to hold metadata only, it is sufficient to attach one tiebreaker volume (so create one tiebreaker disk) per file system. If you use an external IBM Storage Scale Tiebreaker node, you add the tiebreaker disk to the file system by running the createTieDisk operation. For details, see Adding tiebreaker disks to an external IBM Storage Scale Tiebreaker node.
        Note: The tiebreaker disks are automatically created when the external tiebreaker node is first attached to the Primary cluster, so you need to add a tiebreaker disk only if the file system was created after the tiebreaker node was attached to the cluster.

        If you use a IBM Storage Scale Tiebreaker node that was created by using the IBM Storage Scale Tiebreaker template, attach a volume to the tiebreaker instance as you did for the mirror instance. Because the tiebreaker volume is used to hold metadata only, it is sufficient to create one tiebreaker volume per file system, with a size of 1 GB. You can attach as many volumes as you want to the primary and mirror for a file system; the tiebreaker needs to attach only one tiebreaker volume for that file system.

  • If you are attaching the volume to an existing file system:
    1. Attach the volume to the Mirror instance (for active-active configuration) first.
    2. Attach a volume (of the same size and for the same file system that you attached to the Mirror instance) to the Primary instance last.
  • Before adding volumes to an existing file system on the Primary instance, you must add the same number of volumes (and of the same size) to the Mirror instance first.
  • When you attach a Mirror instance to an existing Primary instance, you must have the same number of volumes for the file system specified and of the same size, as exist on the Primary instance. For example, if the Primary instance has a file system testFSys with five 1 GB volumes attached, then when you create the Mirror configuration, you must specify the same file system testFSys with five 1 GB volumes.
  • For every new file system that you create, you must define one tiebreaker volume for that file system. Because the tiebreaker volume holds metadata only, the size of the tiebreaker volume can be 1 GB.
  • Any volumes that you attach must be newly created and cannot have been previously used or partitioned by other entities.
  • The selection menu prompts you to select the right type of storage based on your deployment setting. As a result, if you are attaching a volume to a one node configuration, you can select only from a list of available block volumes to be used by the IBM Storage Scale shared file systems. When you attach a volume to a configuration with multiple nodes, you can select only from a list of available block shared volumes.

Procedure

  1. Expand the Manage Storage Volumes section of the GPFS_Manager operations.
  2. Expand the Attach Storage Volumes node.
  3. In the File System name field, specify the IBM Storage Scale file system name to associate with the volumes being attached.
    To create and configure a new file system, select the Create new file system check box.
  4. In the Shared Volumes field, click Select to select one or more shared volumes that are available to be attached to this IBM Storage Scale configuration.
  5. Click Submit.
  6. Click Confirm when asked to validate your request.

Results

A new entry is displayed under the Operation Execution Results list, with the name Attach Storage Volumes. When completed, the status of the operation changes from Active to Done, and the Return Value column displays a message that the operation has been performed, and a link to the resulting log file, similar to the following example:
GPFS-Manager.11402320054789.GPFS_Manager: Attach volume has been invoked. Click here to open the log status.

Click the link to display the log results showing the results of the operation. Verify that there are no errors in this log.

What to do next

After attaching a volume, the attached volume is still displayed in the Operations page as available to attach, until you refresh the page. Be sure to refresh the Operations page before attempting to attach or detach volumes. After refreshing the page, the newly attached volume is displayed in the list of volumes available to be detached.