Virtual Fabrics
This chapter describes Virtual Fabrics, provides examples of how to implement this feature, and highlights a sample environment where Virtual Fabrics are deployed.
Virtual Fabrics is an architecture to virtualize hardware boundaries. The Virtual Fabrics feature allows storage area network (SAN) design and management to be done at the granularity of a port. It is done by allowing a customer to partition a single physical switch into multiple Logical Switches.
This chapter includes the following sections:
8.1 IBM b-type Virtual Fabric
This section explains what the IBM b-type Virtual Fabrics feature is, and how it is configured to an operational state.
8.1.1 Virtual Fabrics introduction
IBM b-type Virtual Fabrics allows IT organizations to manage IT assets by corporate function, use different permission levels for SAN administrators, and maintain required levels of data and fault isolation without increasing cost and complexity. In addition, Virtual Fabrics can reduce hardware costs by optimizing resource utilization.
Physical switches can be partitioned into independently managed logical switches, each with their own data, control, and management paths.
Logical switches can allocate fabric resources “by the port” rather than by the switch. They also provide a way to simplify charge-back for storage by customer, department, or application while cost-effectively consolidating SAN resources. Because logical switches do not need to be enabled on every switch in a SAN, deployment is simple and nondisruptive in existing environments.
8.1.2 Logical switches and logical fabrics
This section describes some of the capabilities of logical switches and logical fabrics.
Figure 8-1 introduces logical switches and logical fabrics.
Figure 8-1 Logical switches and logical fabrics
Layer-2 traffic isolation is available with a special extended inter-switch link (XISL) shared by multiple logical fabrics, or with dedicated inter-switch link (ISL) connections between logical switches in the same logical fabric. Both ISL and XISL connections can use front ports or inter-chassis link (ICL) connections with frame trunking and dynamic path selection (DPS) for full bandwidth utilization. The logical fabrics capability supports Integrated Routing at Layer 3. Routing connections attach an integrated backbone fabric to multiple edge fabrics. Zoning allows traffic to flow between devices in any edge fabric.
Virtual Fabrics was introduced with FOS 6.2.0. It is available on IBM b-type Gen 5 16 Gbps products that are Virtual Fabrics-capable such as the IBM SAN768B, IBM SAN384B, IBM SAN80B, the IBM SAN40B switches. For investment protection, products that are not Virtual Fabrics capable (such as earlier 2 and 4 Gbps Fabric Operating System (FOS) products) can seamlessly connect to Virtual Fabrics-capable products without requiring a reconfiguration of the existing switches. See Table 8-1.
Table 8-1 Supported logical switch creation limits
|
Platform
|
Maximum Logical
Switches1/Chassis
|
|
SAN768B
|
8
|
|
SAN384B
|
8
|
|
SAN80B-4
|
4
|
|
SAN48B-5
|
3
|
1 Numbers include the Default Switch and Base Switch.
|
Important: On the SAN80B-4 and the SAN40B-4 switches, the Default Switch and Base Switch can be the same.
|
To simplify Virtual Fabrics management, organizations can use IBM Network Advisor. After they are created, logical switches and fabrics are managed the same as their physical counterparts. Alternatively, organizations can use the standard FOS command-line interface (CLI) to enter commands or script configuration and management operations for Virtual Fabrics.
The Virtual Fabrics (VF) feature is easy to set up and simple to manage for “port-level” partitioning of physical switches into independent logical switches. It does not reduce fabric or chassis scalability, preserving ROI and seamlessly supporting advanced FOS features. These feature include frame trunking, DPS, Fibre Channel Routing, Adaptive Networking, Access Gateway, Access Gateway trunking, and Fibre Channel over IP (FCIP) for extension.
8.2 Virtual Fabric features
This section describes different features of Virtual Fabrics.
The Virtual Fabrics suite consists of the following specific features:
•Logical switch
•Logical fabric
•Device sharing
For more information, see the Fabric OS version 7.4 Administrators Guide at the following website:
8.2.1 Logical switch
A logical switch is the fundamental component of a Virtual Fabric. When enabled on a VF-capable switch, Virtual Fabrics allows users to divide the switch into multiple logical switches. Ports in the physical switch can be dynamically allocated to any logical switch in the chassis, and can be reallocated to logical switches as needed. Port, switch, and fabric management are performed in the same way as for physical switches or fabrics.
Default logical switch
The default logical switch (default switch) is automatically created when Virtual Fabrics is enabled on a VF-capable switch. Initially, the default switch contains all the physical switch resources and ports. For director switches, the ports on any blade that is inserted into the chassis initially belong to the default switch. Ports that are required by user-defined logical switches are dynamically allocated from the default switch by the chassis administrator. When the Virtual Fabrics feature is enabled, there is a default switch even when all ports in the default switch have been allocated to other logical switches. The default switch supports all the same port types as the physical switch.
Base switch
A base switch is a logical switch that is used to communicate among different logical switches. The legacy EX_port is connected to the base logical switch. Also, ISLs connected to the Base Switch are used to communicate among different fabrics. The default logical switch supports E_ and EX_ports.
Logical switch
A logical switch is a collection of zero or more ports that act as a single Fibre Channel (FC) switch. When Virtual Fabrics is enabled on the chassis, there is always at least one default logical switch instance. You must assign each logical switch (default or general) in the same chassis to a different logical fabric. The logical switch supports all E_ and F_ports.
|
Attention: EX_ports are only allowed on the Base Switch.
|
8.2.2 Logical fabric
The Fabric ID (FID) assigned to a logical switch identifies its traffic as belonging to a specific logical fabric. Logical switches in other chassis with the same FID can join into a logical fabric. Logical switches within a logical fabric can be directly connected with ISLs (front ports, ICL connections, or both), supporting frame trunking and DPS. Similar to a physical fabric, the ISL connection carries traffic for a single fabric. An alternative to dedicated ISL connections at Layer 2 uses the base fabric to carry traffic for multiple logical fabrics on the same physical connection, maintaining fabric isolation.
8.2.3 ISL sharing
When a base switch is connected to another base switch, an XISL connection is created. When logical switches with the same FID are configured to use the XISL, the base switches automatically create a Logical ISL (LISL) within the XISL. The LISL isolates traffic from multiple fabrics. Each LISL is dedicated to traffic for a single fabric. The physical XISL connection between two base switches automatically forms an LISL “tunnel” dedicated to the traffic to and from logical switches.
8.2.4 User accounts
Table 8-2 lists the predefined user accounts in Fabric OS that are available in the local switch user database.
Table 8-2 Default local user accounts
|
Account name
|
Logical fabric
|
Description
|
|
admin
|
LF1-128
home: 128
|
Observe-modify permission
|
|
factory
|
LF1-128
home: 128
|
Reserved
|
|
root
|
LF1-128
home: 128
|
Reserved
|
|
user
|
LF1-128
home: 128
|
Observe-only permission
|
The password for all default accounts should be changed during the initial installation and configuration for each switch.
8.3 Configuring Virtual Fabrics
This section describes a limited set of instructions and commands for configuring and managing Virtual Fabrics. For a complete list, see the Fabric OS version 6.2.0 Administrators Guide and Fabric OS Command Reference Manual available only through the Partner Network website (go to Product Documentation and register or log in):
Virtual Fabrics can be managed with Data Center Fabric Manager (IBM Network Advisor). This section demonstrates how to configure VF by using the standard Fabric OS v6.4.+ CLI and IBM Network Advisor.
8.3.1 Changing the context to a different logical switch
When Virtual Fabric is enabled, you want to move between the defined virtual switches. This process can be done with either Web Tools or the setcontext command from the CLI.
Here is one method to change the context:
1. Connect to the physical chassis and log in with an account that is assigned to the admin role.
2. Set the context to the logical switch that you want to manage (if you are not already in that context). Example 8-1 shows how to switch to FID 20.
Example 8-1 Changing the logical switch context to FID 20
IBM_SAN384B_27:admin> setcontext 20
8.3.2 Enabling Virtual Fabrics
Virtual Fabrics is disabled by default on switches that you upgrade to Fabric OS v6.2.0 or later. Virtual Fabrics is enabled by default on a new chassis. Before you can use the Virtual Fabrics features, such as logical switch and logical fabric, you must enable Virtual Fabrics.
|
Attention: When you enable Virtual Fabrics, the Control processor blades (CPs) are rebooted and all EX_Ports are disabled after the reboot.
|
Using IBM Network Advisor
Complete the following steps to enable Virtual Fabrics:
1. Right-click the switch where VF will be configured to display the drop-down menus for the switch and select Enable Virtual Fabric as shown in Figure 8-2.
|
Requirement: SNMP V3 must be enabled and configured for management of Virtual Fabrics.
|
Figure 8-2 Enable Virtual Fabric
A warning message is displayed as shown in Figure 8-3.
Figure 8-3 VF warning message
2. Read the warning message and select the OK button to continue.
When this operation is completed and the reboot is done, you will see a V symbol above the VF enabled switch and a chassis group appears in the product list, as shown in Figure 8-4.
Figure 8-4 VF enabled switch
Using the command-line interface
To manage virtual fabrics, you must have admin privileges on the switch chassis.
Example 8-2 shows how to check whether Virtual Fabrics is enabled or disabled and then enable it.
Example 8-2 Enabling Virtual Fabrics
IBM_SAN384B_27:admin> fosconfig --show
FC Routing service: enabled
iSCSI service: Service not supported on this Platform
iSNS client service: Service not supported on this Platform
Virtual Fabric: disabled
Ethernet Switch Service: disabled
IBM_SAN384B_27:admin> fosconfig --enable vf
WARNING: This is a disruptive operation that requires a reboot to take effect.
All EX ports will be disabled upon reboot.
Would you like to continue [Y/N]: y
8.3.3 Disabling Virtual Fabrics
This section describes how to disable Virtual Fabrics.
Using IBM Network Advisor
Complete the following steps to disable Virtual Fabrics in IBM Network Advisor:
1. Select the switch in the chassis group that is displayed in the product list, right-click to open the drop-down menu options, and select the option to disable Virtual Fabrics, as shown in Figure 8-5.
Figure 8-5 Disable Virtual Fabric
A warning message appears. This is the same warning message that is shown for enabling the VF, as shown in Figure 8-3 on page 219.
2. Read the warning and select OK to close the window.
Using the command-line interface
Example 8-3 shows how to use the CLI to check whether Virtual Fabrics is enabled or disabled, and then disable it.
Example 8-3 Disabling Virtual Fabrics
IBM_SAN384B_27:admin> fosconfig --show
FC Routing service: disabled
iSCSI service: Service not supported on this Platform
iSNS client service: Service not supported on this Platform
Virtual Fabric: enabled
IBM_SAN384B_27:FID128:admin> fosconfig --disable vf
WARNING: This is a disruptive operation that requires a reboot to take effect.
Would you like to continue [Y/N]: y
VF has been disabled. Your system is being rebooted.
|
Attention: Enabling and disabling Virtual Fabrics is disruptive and will reboot the switch.
|
8.3.4 Logical switch management
IBM Network Advisor is used to manage logical switches after Virtual Fabrics is enabled. From the IBM Network Advisor Configure drop-down menu, right-click the switch and select Logical Switches, as shown in Figure 8-6.
Figure 8-6 Logical switches IBM Network Advisor
The Logical Switches management window is displayed as shown in Figure 8-7. When Virtual Fabrics is enabled, a base switch is automatically created with an FID of 128, the same as the backbone switch, and all ports in the switch are placed into this base switch.
Figure 8-7 Logical Switch management
8.3.5 Modifying the base switch
To modify the base switch, select the base switch from the Logical Switches window and select the Edit button. You can modify all base switch parameters, as shown in Figure 8-8.
Figure 8-8 Edit Properties
After the configuration edit is complete, Click OK in the Edit window, and then click OK in the Logical Switches management window.
This action opens a confirmation window. Read the message on the window and select OK. The system then performs a configuration operation and displays the progress of the command under the status field, as shown in Figure 8-9.
Figure 8-9 Confirmation window
8.3.6 Creating a logical switch
When the logical switch is created, it is automatically enabled and it has no ports assigned. Complete the following steps to create a logical switch:
1. Open the Logical Switches view and select the New Fabric option. This action opens the New Logical Fabric template.
Figure 8-10 New Logical Fabric Template
The new logical fabric is displayed in the Logical Switches window.
Figure 8-11 Adding a switch
The new logical switch window opens.
4. Configure the new logical switch as required by modifying the fields as shown in Figure 8-12.
Figure 8-12 New logical switch fabric parameters
Under the Switch option, you can change the switch name and domain ID, as shown in Figure 8-13.
Figure 8-13 New logical switch
5. Click OK to add the switch.
6. From the logical switch window, select the new logical switch and add the ports that are required for this switch by selecting them and adding them to the newly created logical switch, as shown in Figure 8-14. This process can be used at any time to add or delete ports from the logical switch.
Figure 8-14 Add ports to logical switch
7. Click OK to process the new configuration.
The Logical Switch Change Confirmation and Status window is displayed.
Read the information in the Logical Switch Change Confirmation and Status window and then click Start to complete the addition of the logical switch, as shown in Figure 8-15.
Figure 8-15 Logical switch change confirmation and status
The status bar displays the status of the activation. It will change to Success when completed, and the newly created fabric and switch will be displayed in IBM Network Advisor, as shown in Figure 8-16.
Figure 8-16 Logical Switch Status
Figure 8-17 shows the logical switch.
Figure 8-17 IBM Network Advisor logical switch
8.3.7 Deleting a logical switch
Complete the following steps to delete a logical switch:
1. Open the Logical Switches configuration window, select the switch that you want to delete, and click Delete.
Figure 8-18 Delete switch
3. When the delete is completed, click OK to activate the new configuration.
|
Important: The default logical switch cannot be deleted.
|
8.3.8 Displaying the logical switch configuration
Example 8-4 shows the configuration that is created by using the CLI.
Example 8-4 To display the logical switch configuration
IBM_SAN384B_27_VF:FID128:admin> lscfg --show
Created switches: 128(ds) 1
Slot 1 2 3 4 5 6 7 8
-------------------------------------------------------
Port
0 | 128 | | 128 | | | 128 | 128 | 128 |
1 | 128 | | 128 | | | 128 | 128 | 128 |
2 | 128 | | 128 | | | 128 | 128 | 128 |
3 | 128 | | 128 | | | 128 | 128 | 128 |
4 | 1 | | 128 | | | 128 | 128 | 128 |
5 | 1 | | 128 | | | 128 | 128 | 128 |
6 | 1 | | 128 | | | 128 | 128 | 128 |
7 | 1 | | 128 | | | 128 | 128 | 128 |
8 | 1 | | 128 | | | 128 | 128 | 128 |
9 | 128 | | 128 | | | 128 | 128 | 128 |
10 | 128 | | 128 | | | 128 | 128 | 128 |
11 | 128 | | 128 | | | 128 | 128 | 128 |
12 | 128 | | 128 | | | 128 | 128 | 128 |
13 | 128 | | 128 | | | 128 | 128 | 128 |
14 | 128 | | 128 | | | 128 | 128 | 128 |
15 | 128 | | 128 | | | 128 | 128 | 128 |
16 | 128 | | | | | | | 128 |
17 | 128 | | | | | | | 128 |
18 | 128 | | | | | | | 128 |
19 | 128 | | | | | | | 128 |
20 | 128 | | | | | | | 128 |
21 | 128 | | | | | | | 128 |
22 | 128 | | | | | | | 128 |
23 | 128 | | | | | | | 128 |
24 | 128 | | | | | | | 128 |
25 | 128 | | | | | | | 128 |
26 | 128 | | | | | | | 128 |
27 | 128 | | | | | | | 128 |
28 | 128 | | | | | | | 128 |
29 | 128 | | | | | | | 128 |
30 | 128 | | | | | | | 128 |
31 | 128 | | | | | | | 128 |
8.3.9 Changing the fabric ID of a logical switch
Complete the following steps to change the fabric ID of an existing logical switch:
1. Select the Logical Switches window and click Edit. This step opens the Edit Properties window, where you can change the logical fabric ID, as shown in Figure 8-19.
Figure 8-19 Change Logical Fabric ID
The fabric ID indicates in which fabric the logical switch participates. By changing the fabric ID, you are moving the logical switch from one fabric to another.
In the Logical Switches window, the switch will display under the new fabric ID, as shown in Figure 8-20.
Figure 8-20 Logical Switch view with changed ID
2. To activate the change, click OK on the Logical Switches window, then read the confirmation message and click Start to complete the operation.
The updated logical fabric ID is displayed in the logical switch view as shown in Figure 8-21.
Figure 8-21 Updated logical fabric ID in the logical switch view
8.3.10 Changing a logical switch to a base switch
Only the base switch can be used for ISLs. If there is no base switch, you might want to change one of the logical switches to a base switch.
Complete the following steps to change a logical switch to a base switch:
1. Select the logical switch in the Logical Switch View window and click Edit.
The Edit Properties window displays.
Figure 8-22 Edit Properties base unit
3. To activate the change, click OK in the Logical Switches window, read the confirmation message, and click Start to complete the operation.
|
Important: Trunk areas must be disabled to change a switch into a base switch. You can do this using the porttrunkarea --disable all command. The switch must be disabled to run this command successfully.
|
8.3.11 Configuring a logical switch for XISL use
When you create a logical switch, by default it is configured to use XISLs. Use the following procedure to allow or disallow the logical switch to use XISLs in the base fabric.
1. Run the switchshow command to check whether the switch is enabled for XISL use as shown in Example 8-5.
Example 8-5 Check XISL with the switchshow command
IBM_SAN384B_213:FID128:admin> switchshow
switchName: IBM_SAN384B_213
switchType: 77.3
switchState: Online
switchMode: Native
switchRole: Principal
switchDomain: 1
switchId: fffc01
switchWwn: 10:00:00:05:1e:94:3a:00
zoning: OFF
switchBeacon: OFF
FC Router: OFF
Allow XISL Use: OFF
LS Attributes: [FID: 128, Base Switch: No, Default Switch: Yes]
Index Slot Port Address Media Speed State Proto
===================================================
0 1 0 010000 -- N4 No_Module
1 1 1 010100 -- N4 No_Module
2 1 2 010200 -- N4 No_Module
2. Run the switchdisable command to disable the switch. No output will be returned.
Example 8-6 use configure to allow or disallow XISL use
switch_100:FID100:admin> configure
Configure...
Fabric parameters (yes, y, no, n): [no] y
Domain: (1..239) [1] 100
Allow XISL Use (yes, y, no, n): [yes]
Enable a 256 Area Limit
(0 = No,
1 = Zero Based Area Assignment,
2 = Port Based Area Assignment): (0..2) [0]
R_A_TOV: (4000..120000) [10000]
E_D_TOV: (1000..5000) [2000]
WAN_TOV: (0..30000) [0]
MAX_HOPS: (7..19) [7]
Data field size: (256..2112) [2112]
Sequence Level Switching: (0..1) [0]
Disable Device Probing: (0..1) [0]
Suppress Class F Traffic: (0..1) [0]
Per-frame Route Priority: (0..1) [0]
Long Distance Fabric: (0..1) [0]
BB credit: (1..27) [16]
Disable FID Check (yes, y, no, n): [no]
Insistent Domain ID Mode (yes, y, no, n): [no]
Virtual Channel parameters (yes, y, no, n): [no]
F-Port login parameters (yes, y, no, n): [no]
Zoning Operation parameters (yes, y, no, n): [no]
RSCN Transmission Mode (yes, y, no, n): [no]
Arbitrated Loop parameters (yes, y, no, n): [no]
System services (yes, y, no, n): [no]
Portlog events enable (yes, y, no, n): [no]
ssl attributes (yes, y, no, n): [no]
rpcd attributes (yes, y, no, n): [no]
webtools attributes (yes, y, no, n): [no]
WARNING: The domain ID will be changed. The port level zoning may be affected
4. Respond to the remaining prompts or press Ctrl+D to accept the other settings and exit.
5. Run the switchenable command to re-enable the switch. No output will be returned.
8.3.12 Creating a logical fabric that uses XISLs
The following procedure describes the flow of creating a logical fabric that uses XISLs, but does not provide every required detail.
Complete these steps to create a logical fabric that uses multiple chassis and XISLs:
1. Set up the base switches in each chassis:
a. Connect to the physical chassis and log in using an account assigned to the admin role with the chassis-role permission.
b. Enable the Virtual Fabrics feature, if it is not already enabled. This feature automatically creates the default logical switch, with FID 128. All ports in the chassis are assigned to the default logical switch.
c. Create a base switch and assign it a fabric ID that will become the FID of the base fabric.
d. Assign ports to the base switch.
e. Repeat these steps for all chassis that are to participate in the logical fabric.
2. Physically connect ports in the base switches to form XISLs.
3. Enable all of the base switches. This process forms the base fabric.
4. Configure the logical switches in each chassis:
a. Connect to the physical chassis and log in using an account assigned to the admin role with the chassis-role permission.
b. Create a logical switch and assign it a fabric ID for the logical fabric. This FID must be different from the FID in the base fabric.
c. Assign ports to the logical switch.
d. Physically connect devices and ISLs to the ports on the logical switch.
e. (Optional) Configure the logical switch to use XISLs, if it is not already XISL-capable. By default, newly created logical switches are configured to allow XISL use.
f. Repeat these steps for all chassis that are to participate in the logical fabric, using the same fabric ID whenever two switches need to be part of a single logical fabric.
5. Enable all logical switches by using the switchenable command.
Now the logical fabrics are formed.
The fabricShow command displays all logical switches that are configured with the same fabric ID as the local switch and all non-Virtual Fabric switches connected through ISLs to these logical switches.
The switchShow command displays logical ports as E_Ports, with -1 for the slot and the user port number for the slot port.
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