Automatic iSCSI Optimization

The following steps will enable automatic iSCSI optimization on interfaces.  This will also enable jumbo frame support across all interfaces on the 55xx series - note that jumbo frame support will be available after the configuration has been saved and the switch has been reset to adjust for the new frame size.

CLI:

1. Login to the CLI and enable iSCSI optimization globally:

console>enable
console#configure
console(config)#iscsi enable

Switch output:

Enabling iSCSI also automatically enables jumbo-frames. However, jumbo-frames will be enabled only after copying running configuration to startup configuration and resetting the device

2. Verify that jumbo frames will be enabled after reset:

console(config)#exit
console#show ports jumbo-frame

Jumbo frames are disabled
Jumbo frames will be enabled after reset

3. Save the configuration:

console#copy running-config startup-config


Overwrite file [startup-config] ?[Yes/press any key for no]....
%COPY-I-FILECPY: Files Copy - source URL running-config destination URL flash://startup-config
%COPY-N-TRAP: The copy operation was completed successfully
Copy succeeded
4. Reset the switch:

console#reload


This command will reset the whole system and disconnect your current session. Do you want to continue ? (Y/N) Y
Shutting down...

Web UI:


1. Navigate to Switching > iSCSI Optimization > Global Parameters. Set "iSCSI Status" to "Enable", then click Apply.

2. Click OK to acknowledge that jumbo frames support will require a switch reset:

3. Verify that the configuration was successfully applied:

4. To save the switch configuration, navigate to System > File Management > Copy Files. Verify that "Copy Configuration" is selected with source "Running Configuration" and destination "Startup Configuration", then click Activate.

5. Once the configuration has been copied, click Close:

6. To reset the switch to activate jumbo frame support, navigate to System > Stack Management > Reset. Select "Reset Device", then click Apply. Note that this will drop all traffic for several minutes while the switch management is restarted.

7. Click OK to confirm the reset

Jumbo Frames

Jumbo frame support is disabled by default and is configured globally for all interfaces - enabling jumbo frame support is effective after a switch reset:

CLI:

1. Login to the CLI and enable jumbo frame support globally:


console>enable
console#configure
console(config)#port jumbo-frame

This setting will take effect only after copying running configuration to startup configuration and resetting the device



2. Verify that jumbo frames will be enabled after reset:

console(config)#exit
console#show ports jumbo-frame


Jumbo frames are disabled
Jumbo frames will be enabled after reset

3. Save the configuration:

console#copy running-config startup-config


Overwrite file [startup-config] ?[Yes/press any key for no]....
%COPY-I-FILECPY: Files Copy - source URL running-config destination URL flash://startup-config
%COPY-N-TRAP: The copy operation was completed successfully
Copy succeeded

4. Reset the switch:

console#reload

This command will reset the whole system and disconnect your current session. Do you want to continue ? (Y/N)
Shutting down ...

5. After the switch has reset, verify that jumbo frames are now enabled:

console>enable
console#show ports jumbo-frame

Jumbo frames are enabled
Jumbo frames will be enabled after reset


Web UI:

1. Navigate to Switching > Ports > Jumbo Frames. Set "New Setting" to "Enabled", then click Apply:

2. Verify that the configuration was successfully applied:

3. Save the configuration via System > File Management > Copy Files - this process is described above in "Automatic iSCSI Optimization". After reset, verify that jumbo frames support is now enabled:

Spanning Tree PortFast

The PowerConnect 55xx series switches run IEEE 802.1w Rapid Spanning Tree Protocol by default. For interfaces connected directly to SAN and host NICs, enabling spanning tree portfast ensures that the switch interfaces begins passing traffic immediately when a link is detected, and prevents unnecessary spanning tree topology changes if the interface link state changes (for example, if a host is rebooted). Spanning tree portfast is disabled by default, and is referred as "Fast Link" via the web UI.

Note that spanning tree portfast typically should not be enabled on interfaces attached to other network devices (switches, routers, firewalls, etc) to ensure that any network loops are detected prior to passing traffic through the interface.

CLI:

1. Login to the CLI and enable spanning tree port-fast on the appropriate interfaces - this example configures gigabit interfaces 1-12:

console>enable
console#configure
console(config)#interface range gigabitethernet 1/0/1-12
console(config-if-range)#spanning-tree portfast

2. Verify that spanning tree port-fast is enabled on the interface:

console(config-if-range)#end
console#show spanning-tree

Spanning tree enabled mode RSTP
...
...
Interfaces
Name State Prio.Nbr Cost Sts Role PortFast Type
--------- -------- -------- -------- ------ ---- -------- -----------------
gi1/0/1 enabled 128.1 2000000 Dsbl Dsbl Yes -
gi1/0/2 enabled 128.2 2000000 Dsbl Dsbl Yes -
...
...

3. Save the configuration:

console#copy running-config startup-config


Overwrite file [startup-config] ?[Yes/press any key for no]....
%COPY-I-FILECPY: Files Copy - source URL running-config destination URL flash://startup-config
%COPY-N-TRAP: The copy operation was completed successfully
Copy succeeded


Web UI:

1. After logging into the web UI, navigate to Switching > Spanning Tree -> STP Port Settings > Edit. Select an interface to configure, select "Fast Link", then click Apply:

2. After configuring each appropriate interface, select "Summary" to verify that "Fast Link" is enabled:

3. Save the configuration via System > File Management > Copy Files - this process is described above in "Automatic iSCSI Optimization".

Flow Control

Flow control support is enabled by default on all interfaces and can be configured on a per-interface basis, effective immediately:

CLI:

1. Login to the CLI and enable flow control on the necessary interfaces - this example configures gigabit interfaces 1-48 on the PowerConnect 5548:

console>enable
console#configure
console(config)#interface range gigabitethernet 1/0/1-48
console(config-if-range)#flowcontrol on
2. Save the configuration:
console(config-if-range)#end
console#copy running-config startup-config

Overwrite file [startup-config] ?[Yes/press any key for no]....
%COPY-I-FILECPY: Files Copy - source URL running-config destination URL flash://startup-config
%COPY-N-TRAP: The copy operation was completed successfully
Copy succeeded

Web UI:


1. Navigate to Switching > Ports > Port Configuration > Edit. Select an interface to configure, set Flow Control to "Enable", then click Apply:

2. Save the configuration via System > File Management > Copy Files - this process is described above in "Automatic iSCSI Optimization".

Storm Control


The PowerConnect 55xx series switches support broadcast storm control - this feature is disabled by default on all interfaces. If the switch has previously been configured to use broadcast storm control for a non-iSCSI environment, use the following steps to disable broadcast storm control:

CLI:

1. Login to the CLI and disable broadcast storm control on the necessary interfaces - this example configures gigabit interfaces 1-48 on the PowerConnect 5548:

console>enable
console#configure
console(config)#interface range gigabitethernet 1/0/1-48
console(config-if-range)#no storm-control broadcast enable
2. Verify that broadcast storm control is disabled:


console(config-if-range)#end
console#show storm-control


Port State Admin Rate Oper Rate [Kbits/Sec] Included
-------- -------- ---------- --------------------- ------------------
gi1/0/1 Disabled 8500 8500 BC
gi1/0/2 Disabled 8500 8500 BC
gi1/0/3 Disabled 8500 8500 BC
...

3. Save the configuration:

console(config-if-range)#end
console#copy running-config startup-config

Overwrite file [startup-config] ?[Yes/press any key for no]....
%COPY-I-FILECPY: Files Copy - source URL running-config destination URL flash://startup-config
%COPY-N-TRAP: The copy operation was completed successfully
Copy succeeded

Web UI:


1. After logging into the web UI, navigate to Switching > Ports > Storm Control > Edit. Select an interface to configure, set Broadcast Control to "Disable", then click Apply:

2. After configuring each appropriate interface, select "Summary" to verify that broadcast storm control is disabled:

3. Save the configuration via System > File Management > Copy Files - this process is described above in "Automatic iSCSI Optimization".

The settings above can also be utilized in a VMware virtualized environment.

External links