SANRAD V-Switch manual Resizing a Volume, Advanced Volume Operations 153

If you are working in a V-Switch cluster, a volume must be resized on both V Switches.

Resizing a Volume

You can increase a virtual volume’s potential capacity using the CLI command volume resize. This is the first step in increasing a virtual volume’s actual capacity. Potential capacity is the maximum capacity a volume could be. Actual capacity is the capacity that the server recognizes a virtual volume as having.

Resizing a volume is done while the top-level volume in the hierarchy is exposed on an iSCSI target. Simple, snapshot, concatenated and previously resized volumes can be resized. Resizing a volume concatenates a new volume with the source volume. Only a simple volume can be used to resize a simple or snapshot volume.

After one or more volumes in a hierarchy are resized, the volume must be expanded to make its actual capacity equal to its new potential capacity. See “Expanding a Volume,” page 158.

In Figure 84, is a mirrored volume with a potential capacity of one terabyte. The smallest child of the mirrored volume determines the mirrored volume’s potential capacity. Resizing the one-terabyte child to two terabytes will increase the mirrored volume’s potential capacity to two terabytes. The actual capacity of the mirrored volume remains unchanged until it is expanded to match its potential size.

Mir

1T

Ch 1 Ch 2

1T

2T

Sim3

1T

10251

Figure 84. Asymetrical Mirrored Volume

When a simple or snapshot volume is resized with another simple volume, the first step in their resize concatenation is the creation of a cube. A cube is a special type of volume intermediary created for resizing a volume through concatenation. In Figure 85, page 154, the original connection to the child to resize is broken and transferred to the cube. A cube’s default alias is X+resized volume’s alias. In Figure 85, page 154, the alias of the volume to resize is Ch2; the alias of the cube isXCh2.

Chapter 8: Advanced Volume Operations 153