Graphical User Interface › Class Editor -- Simple Appliances › Volumes Tab

Volumes Tab

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The Volumes tab allows you to create and destroy the set of volumes required for the operation of the appliance.

Note: See OS Limitations for details related to the maximum number of volumes supported by each OS.

Volume Information

For each volume, the following fields are defined:

Name

Logical name of the volume within the appliance. This name represents the role of the volume for the appliance class. It is a single word, case-sensitive, alphanumeric ([A-Za-z0-9_]).

Mount on

Path where the volume should be automatically mounted inside of the appliance (for example, /mnt/data). If left empty, it is up to the appliance to mount the volume.
For Windows appliances, boot volumes may only be mounted as c or c:\. The mount path for non-boot volumes can be only one of the following: letter, letter:\, or c:\path where letter is any valid drive letter except for c and path is not empty.
The mount path for the boot volume does not need to be set to c or c:\ as this will be done automatically by CA AppLogic® for System z.
This feature is only available if the Configuration Mode is set to dhcp.

Device

Name of a device, on which CA AppLogic® for System z makes the volume available to the appliance. For Linux appliances this is typically in the form of /dev/hdaN, where N is a digit between 1 and 9. The appliance itself determines in its /etc/fstab configuration file how and where in the filesystem hierarchy the volume is mounted unless Mount on path is specified.

Boot

Determines the boot volume for the appliance. Each appliance MUST have a boot volume, otherwise it will not start. See the Appliance Creation Guide for more information about how to create an appliance boot volume.

Type

Volume type. CA AppLogic® for System z supports the following volume types:

• Instantiable : A class volume of the appliance that needs to be instantiated for each appliance instance. CA AppLogic® for System z makes a separate copy of such volumes for each instance of the appliance. Most boot volumes are of this type. Press button to create a new volume.
• Placeholder : A placeholder for a volume that can be configured with an application volume for the appliance instance. The appliance class itself does not carry the volume. Each appliance instance is configured explicitly with a volume from the application. Most content, data and code-containing volumes are of this type.
• Common : This type of class volume is shared between all instances of the appliance class. All instances access the same volume and it must be read-only. No separate copy of the volume is made.
  This volume type is useful for large read-only data sets that are not used heavily.
• Blank : An empty volume, that will be created for each appliance instance.
  The blank volume type is similar to the instantiable volume type, except that no template volume exists for the class and instance volumes are created empty (unformatted). This type of volumes may be useful for appliances that hold user data (like database and other).

  Size

  Volume size for blank volumes. This field defines the size of the volume that CA AppLogic® for System z will create. The size is specified as integer with optional M or G suffix (for example, 256M). This field is shown and needed only for volumes of type blank. For all other volumes, CA AppLogic® for System z gets the volume size from the volumes themselves.

Constraints

Performance constraints for the volume. There are three volume constraints: none, high bandwidth and local only. CA AppLogic® for System z currently ignores the constraints setting, as such this setting should not be used.

Options

A set of important volume options described below.
The mandatory attribute makes the placeholder volumes required (currently all volumes are required, so this attribute is not used).
The read-only attribute makes the volume read-only (write-protected) for the appliance
The shared attribute marks the volume as shareable between appliances (see a number of cautions below)

Important: When there is no Mount on path specified, it is the responsibility of the appliance to mount a volume itself whenever it needs it in the file system and needs to select the r/o or r/w option on the mount within /etc/fstab to specify the type of access to the file system. The R/O and R/W setting in the editor does not affect how the appliance mounts the volume but only how it can mount it. For example, if a volume is specified as R/O in the editor then the appliance can only mount the volume as R/O. However, if the volume is specified as R/W in the editor, the appliance may mount the volume as R/O or R/W.

Volume Operations

Add

Add a new volume to the class. Press this button to create a new volume and assign it to the class.

Delete

Delete the selected volume. This operation permanently removes the volume from the class and from the grid. All volume content is lost. There is no undelete.
You cannot remove a volume that is currently used by the appliance.

Rename

Rename the selected volume.

Resize

Resize the selected volume. This operation changes the size of the volume.

Manage

Manage the selected volume. This operation provides access to the volume contents via a web browser. Files may be uploaded, downloaded, edited, deleted, and so on. See the Volume Browser Reference for more information.

Cautions:

• don't make a volume shared unless it is also read-only (shared r/w access will corrupt the filesystem)
• don't make boot volumes read-only unless you have configured the boot volume specifically for this
• when making a volume read-only, help ensure that /etc/fstab is properly configured for read-only mount
• when designing the set of volumes for appliances, keep the user data on a placeholder volume
• when possible, use instantiable volumes instead of blank volumes -- they are easier

Note:

• Combining the read-only and shared attributes allows you to share read-only volumes between appliances. Further, you can define properties to configure root directories, so that multiple appliances can use the same volume to obtain different file sets from it (for example, HTML content, application code, and so on.)
• You can arrange the order of the volumes in the list using the up and down arrows. The order affects only how the volumes will be shown to you in the property sheets; it has no runtime impact.