# Adding features to an existing volume

This chapter tells how to add additional EVMS features to an already existing EVMS volume.

## Why add features to a volume?

EVMS lets you add features such as drive linking to a volume that already exists. By adding features, you avoid having to potentially destroy the volume and recreate it from scratch. For example, take the scenario of a volume that contains important data but is almost full. If you wanted to add more data to that volume but no free space existed on the disk immediately after the segment, you could add a drive link to the volume. The drive link concatenates another object to the end of the volume and continues seamlessly.

## Example: add drive linking to an existing volume

The following example shows how to add drive linking to a volume with the EVMS GUI, Ncurses, and CLI interfaces.

> ### Add drive linking to an existing volume

> The following sections show how to add a drive link to volume `/dev/evms/vol` and call the drive link "DL."

> ### NOTE

> Drive linking can be done only on EVMS volumes; therefore, `/dev/evms/vol` must be converted to an EVMS volume if it is not already.

### Using the EVMS GUI

Follow these steps to add a drive link to the volume with the EVMS GUI:

1. Select Actions AddFeature to Volume.

2. Select /dev/evms/vol

3. Click Next.

4. Select Drive Linking Feature.

5. Click Next.

6. Type `DL` in the Name Field.

7. Click Add.

Alternatively, you can perform some of the steps to add a drive link with the GUI context sensitive menu:

1. From the Volumes tab, right click `/dev/evms/vol`.

2. Click Add feature...

3. Continue adding the drive link beginning with step 3 of the GUI instructions.

### Using Ncurses

Follow these steps to add a drive link to a volume with Ncurses:

1. Select Actions Add Feature to Volume.

2. Select /dev/evms/vol.

3. Activate Next.

4. Select Drive Linking Feature.

5. Activate Next.

6. Press Spacebar to edit the Name field.

7. At the "::" prompt enter `DL`.

8. Press Enter.

9. Activate Add.

Alternatively, you can perform some of the steps to add a drive link with the context sensitive menu:

1. From the Volumes view, press Enter on /dev/evms/vol.

2. Activate the Add feature menu item.

3. Continue adding the drive link beginning with step 3 of the Ncurses instructions.

### Using the CLI

Use the `add feature` to add a feature to an existing volume. Specify the command name followed by a colon, followed by any options and the volume to operate on. To determine the options for a given feature, use the following query:

    query: plugins, plugin=DriveLink, list options

The option names and descriptions are listed to help you construct your command. For our example, the command would look like the following:

    add feature: DriveLink={ Name="DL }, /dev/evms/vol