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About Device Alias Modes

Device alias supports two modes: basic and enhanced mode.

• When device alias runs in the basic mode, all applications function like the applications on the Cisco SAN-OS Release 3.0 switches. When you configure the basic mode using device aliases, the application immediately expands to pWWNs. This operation continues until the mode is changed to enhanced.
• When device alias runs in the enhanced mode, all applications accept the device-alias configuration in the native format. The applications store the device alias name in the configuration and distribute it in the device alias format instead of expanding to pWWN. The applications track the device alias database changes and take actions to enforce it.

A native device-alias configuration is not accepted in the interop mode VSAN. IVR zoneset activation will fail in interop mode VSANs if the corresponding twilight zones being injected are native device alias members.

Changing Mode Settings

When the device alias mode is changed from basic to enhanced mode, the applications are informed about the change. The applications start accepting the device alias-based configuration in the native format.

Note Because the device alias was previously running in the basic mode, the applications do not have any prior native device alias configuration.

The applications check for an exisiting device alias cofiguration in the native format. If the device alias is in the native format, the applications reject the request and device alias mode cannot be changed to basic.

All native device alias configurations (both on local and remote switches) must be explicitly removed, or all device alias members must be replaced with the corresponding pWWN before changing the mode back to basic.

Device Alias Mode Distribution

If the device alias distribution is turned on, it is distributed to the other switches in the network whenever there is a change in the mode. You cannot change the mode from basic to enhanced unless all the switches are upgraded to Cisco SAN-OS Release 3.1. The device alias enhancements will not apply unless the entire fabric is upgraded to Cisco SAN-OS Release 3.1.

Note When all the switches are upgraded to Cisco SAN-OS Release 3.1, you cannot automatically convert to enhanced mode. You do not need to change to enhanced mode, you can continue working in the basic mode.

Merging Device Alias

If two fabrics are running different device alias modes and are joined together, the device alias merge will fail. There is no automatic conversion of one mode to the other during the merge process. You will need to resolve the issue.

Note Release 3.0 switches run in basic mode.

At the application level, a merger takes place between the applications and the fabric. For example, zone merge occurs when the E port is up and the IVR/PSM/DPVM merge occurs due to CFS. This merge is completely independent of the device alias merge.

If the application running on an enhanced fabric has a native device alias configuration, the application must fail the merge. The application has to fail the merge even though the other fabric is can support the native device alias-based configuration, but is running in the basic mode. You will need to resolve the issue. Once the device alias merge issue is resolved, each application must be fixed accordingly.

Resolving Merge and Device Alias Mode Mismatch

If two fabrics are running in different modes and the device alias merge fails between the fabrics, the conflict can be resolved by selecting one mode or the other. If you choose the enhanced mode, ensure that all the switches are running at least the Cisco SAN-OS Release 3.1. Otherwise, the enhanced mode cannot be turned on. If you choose the basic mode, the applications running on the enhanced fabric have to comply with the device alias merge.

The device alias merge fails because of mode mismatch, but the application merge succeeds if it does not have any native device alias configurations.

If the native device alias configuration is attempted on an application from a Release 3.1 switch, the commit must be rejected because of device alias mode mismatch on some of the applications.

Note The applications should not accept any native device alias configuration over SNMP if the device alias is running in the basic mode on that particular switch.

Note Confcheck is added when the enhanced mode is turned on and removed when it is turned off. Applications have to add confcheck if they have a device alias configuration in the native format. They have to remove confcheck once the configuration is removed.

Device Alias Features

Device aliases have the following features:

• The device alias information is independent of your VSAN configuration.
• The device alias configuration and distribution is independent of the zone server and the zone server database.
• You can import legacy zone alias configurations without losing data.
• The device alias application uses the Cisco Fabric Services (CFS) infrastructure to enable efficient database management and distribution. Device aliases use the coordinated distribution mode and the fabric-wide distribution scope (refer to the Cisco MDS 9000 Family NX-OS System Management Configuration Guide ).
• When you configure zones, IVR zones, or QoS features using device aliases, and if you display these configurations, the device aliases are automatically displayed along with their respective pWWNs.

Device Alias Requirements

Device aliases have the following requirements:

• You can only assign device aliases to pWWNs.
• The mapping between the pWWN and the device alias to which it is mapped must have a one-to-one relationship. A pWWN can be mapped to only one device alias and vice versa.
• A device alias name is restricted to 64 alphanumeric characters and may include one or more of the following characters:

– a to z and A to Z

– 1 to 9

– - (hyphen) and _ (underscore)

– $ (dollar sign) and ^ (up caret)

Zone Aliases Versus Device Aliases

Table 26-1 compares the configuration differences between zone-based alias configuration and device alias configuration.

Device Alias Databases

The device alias feature uses two databases to accept and implement device alias configurations:

• Effective database—The database currently used by the fabric.
• Pending database—Your subsequent device alias configuration changes are stored in the pending database.

If you modify the device alias configuration, you need to commit or discard the changes as the fabric remains locked during this period.

About Device Alias Distribution

By default, device alias distribution is enabled. The device alias feature uses the coordinated distribution mechanism to distribute the modifications to all switches in a fabric.

If you have not committed the changes and you disable distribution, then a commit task will fail.

About Creating a Device Alias

When you perform the first device alias task (regardless of which device alias task), the fabric is automatically locked for the device alias feature. Once you lock the fabric, the following situations apply:

• No other user can make any configuration changes to this feature.
• A copy of the effective database is obtained and used as the pending database. Modifications from this point on are made to the pending database. The pending database remains in effect until you commit the modifications to the pending database or discard ( abort ) the changes to the pending database.

Fabric Lock Override

If you have performed a device alias task and have forgotten to release the lock by either committing or discarding the changes, an administrator can release the lock from any switch in the fabric. If the administrator performs this task, your changes to the pending database are discarded and the fabric lock is released.

Tip The changes are only available in the volatile directory and are subject to being discarded if the switch is restarted.

About Legacy Zone Alias Configuration Conversion

You can import legacy zone alias configurations to use this feature without losing data if they follow the following restrictions:

• Each zone alias has only one member.
• The member type is pWWN.
• The name and definition of the zone alias should not be the same as any existing device alias name.

If any name conflict exists, the zone aliases are not imported.

Tip Ensure that you copy any required zone aliases to the device alias database as required by your configuration.

When an import operation is complete, the modified alias database is distributed to all other switches in the physical fabric when you perform the commit operation. At this time if you do not want to distribute the configuration to other switches in the fabric, you can perform the abort operation and the merge changes are completely discarded.

Creating Device Aliases

To a create a device alias in the pending database, follow these steps:

To display the device alias configuration, use the show device-alias name command.

To lock the fabric and create a device alias in the pending database, follow these steps:

Step 1 Expand End Devices, and then select Device Alias in the Physical Attributes pane.

You see the device alias configuration in the Information pane.

Step 2 Click the Configuration tab and click the Create Row icon.

You see the Device Alias Creation dialog box.

Step 3 Select a switch from the drop-down menu.

Step 4 Complete the Alias name and pWWN fields.

Step 5 Click Create to create this alias or click Close to discard any unsaved changes.

Distributing the Device Alias Database

To enable the device alias distribution, follow these steps:

Step 1 Expand End Devices and then select Device Alias in the Physical Attributes pane.

You see the device alias configuration in the Information pane.

The CFS tab is the default tab.

Step 2 Select enable from the Global drop-down menus to enabled switch aliases.

Step 3 Select commit from the Config Action drop-down menu for the newly enabled switches.

Step 4 Click Apply Changes to commit and distribute these changes or click Undo Changes to discard any unsaved changes.

Committing Changes

If you commit the changes made to the pending database, the following events occur:

1. The pending database contents overwrites the effective database contents.

2. The pending database is emptied of its contents.

3. The fabric lock is released for this feature.

To commit the changes, follow these steps:

To commit the changes to the device alias database, follow these steps:

Step 1 Expand End Devices, and then select Device Alias in the Physical Attributes pane.

You see the device alias configuration in the Information pane. The CFS tab is the default tab.

Step 2 Select enable from the Global drop-down menus to enable switch aliases.

Step 3 Select commit from the Config Action drop-down menu for the newly enabled switches.

Step 4 Click Apply Changes to commit and distribute these changes or click Undo Changes to discard any unsaved changes.

Discarding Changes

If you discard the changes made to the pending database, the following events occur:

1. The effective database contents remain unaffected.

2. The pending database is emptied of its contents.

3. The fabric lock is released for this feature.

To display the status of the discard operation, use the show device alias status command.

Step 1 Expand End Devices and then select Device Alias in the Physical Attributes pane.

You see the device alias configuration in the Information pane. The CFS tab is the default tab.

Step 2 Select abort from the Config Action drop-down menu.

Step 3 Click Apply Changes to discard the session.

Disabling and Enabling Device Alias Distribution

To disable or enable the device alias distribution, follow these steps:

Examples

To display the status of device alias distribution, use the show device-alias status command (see Example 26-1 and Example 26-2).

Example 26-1 Displays Device Alias Status When Distribution Is Enabled

Example 26-2 Displays Device Alias Status When Distribution Is Disabled

Importing a Zone Alias

To import the zone alias for a specific VSAN, follow these steps:

Examples

To display device alias information in zone sets, use the show zoneset command (see Example 26-3 and Example 26-4).

Example 26-3 Displays the Device Aliases in the Zone Set Information

Example 26-4 Displays the Device Aliases in the Active Zone Set

Using Device Aliases or FC Aliases

You can change whether DCNM-SAN uses FC aliases or global device aliases from DCNM-SAN Client without restarting Cisco DCNM for SAN.

To change whether DCNM-SAN uses FC aliases or global device aliases, follow these steps:

Step 1 Click Server > Admin.

You see the Admin dialog box.

Step 2 For each fabric that you are monitoring with Cisco DCNM for SAN, check the Device Alias check box to use global device aliases, or uncheck to use FC aliases.

Step 3 Click Apply to save these changes or click Close to exit the dialog box without saving any changes.

Populating Device Alias to Interface Description

When an end device is not logged into the switch, the Device Alias is blank. To find out what device is supposed to connect to an FC port when the device is logged out, you can populate the interface description with the device alias when the devices are logged in.

To populate the interface description with the device alias, follow these steps:

Step 1 From the Physical Attributes pane, expand End Devices.

Step 2 From the right pane, click the General tab.

Step 3 Select the rows of FC interfaces.

Step 4 Click the Alias->Description button.

Step 5 Click the commit button.

Rename Device Alias

There are two options for renaming the device alias form SAN client.

To rename the device alias, follow these steps:

Step 1 From the Logical Domains pane, select Data Center > SAN >Fabric name .

Step 2 In the information pane on the right-hand side, click Host Ports or Storage Ports .

Step 3 Double click the Device Alias column and enter the new name.

Step 4 Click the Apply Changes icon.

Another way to rename the device alias is as below:

Step 1 From the Physical Attributes pane, expand End Devices and select Hosts or Storage .

Step 2 Double click the Device Alias column and enter the new name.

Step 3 Click the Apply Changes icon.

Displaying a Failed Status

Example 26-17 Displays a Failed Status

To use administrative privileges and release a locked device alias session, use the clear device-name session command in EXEC mode.

To display the status of the clear operation, use the show device-alias status command.

Device Alias Configuration

Device Alias Mode

Device Alias Discrepancies

Related Document

Standards

RFCs

MIBs