IBM 201 manual Volumes, Name, Read-only or read-write, Retention value, Persistent Images

Persistent Images

This panel lists all of the persistent images that exist on all volumes. On this panel you can:

vCreate a new persistent image immediately (without scheduling it via the Schedules panel).

vDelete an existing persistent image.

vModify properties of an existing persistent image, including read-only or read-write, and retention value.

When you create the persistent image, you can specify properties for the persistent image, including:

Volume(s)	The persistent image can contain a single volume
	or multiple volumes. To select multiple volumes,
	hold down the Ctrl key while clicking on the
	volumes you wish to select. For multi-volume
	persistent images, a virtual directory containing data
	for a volume will appear under the persistent image
	directory in the top level of each volume in the
	persistent image (the name of the persistent image
	directory is configured in the Global Settings panel).
Name	You can name the persistent image. This will be the
	name of the virtual directory containing the
	persistent image, underneath the persistent image
	directory in the top level of the volume (the name of
	the persistent image directory is configured in the
	Global Settings panel).
Read-only or read-write	A persistent image is read-only by default, so no
	modifications can be made to it. However, you can
	set the persistent image to read-write, which
	permits you to modify it. When a persistent image is
	written, the modifications made are also persistent
	(they survive a reboot of the system). Changing a
	persistent image from read-write to read-only resets
	the persistent image to its state at the time you took
	the persistent image, as does selecting Undo
	Writes for a read-write persistent image from the
	Persistent Images panel.
Retention value	A persistent image can be given a relative retention
	value or weight. This is important when PSM needs
	to delete some persistent images for a volume
	because the cache file for the volume for which the
	persistent image was taken capacity has reached a
	certain threshold, as described later in this section.
	If the volume cache file completely fills, then all
	persistent images for that volume are deleted
	regardless of the retention values. By default, a
	new persistent image is assigned a “Normal”
	retention value (there are other higher and lower
	values which can be selected).

38NAS 200 User’s Reference