How to configure jumbo frames on Compellent?

Is the Series 40 interface that different? On our Series 30 you can drill down to Controllers -> (controller name) -> IO Cards -> iSCSI -> (WWN), right click on the WWN of the adapter (not the virtual port) and select properies, IP and MTU are configurable right there

hellraiseruk,

I did some research and was able to find some of our Compellent best practices when it come to iSCSI.

iSCSI Best Practices

· Gigabit Full Duplex connectivity between Storage Center and all local Servers.

· Auto-Negotiate for all interfaces that will correctly negotiate at Gigabit Full Duplex.

· Gigabit Full Duplex hard set for all interfaces that will not correctly negotiate at Gigabit Full Duplex.

· Bi-Directional Flow Control enabled for all switch interfaces that servers or controllers are using for iSCSI traffic.

· Bi-Directional Flow Control enabled for all server interfaces used for iSCSI (Storage Center and QLogic HBA's automatically enable it).

· Bi-Directional Flow Control enabled for all interfaces that handle iSCSI traffic. This includes all devices in between two sites that are used for replication.

· Separate VLAN for iSCSI.

· Two separate networks or VLANs for multipathed iSCSI.

· Two separate IP subnets for the seperate networks or VLANs in multipathed iSCSI.

· Unicast storm control disabled on every switch that handles iSCSI traffic.

· Multicast disabled at the switch level for any iSCSI VLANs.

o Multicast storm control enabled (if available) when multicast can not be disabled.

· Broadcast disabled at the switch level for any iSCSI VLANs.

o Broadcast storm control enabled (if available) when broadcast can not be disabled.

· Routing disabled between regular network and iSCSI VLANs.

· Configure switch interfaces that directly connect to servers or controllers as forwarding only for Spanning Tree (STP).

· Ensure that any switches used for iSCSI are of a non-blocking design.

· When deciding which switches to use, remember that you are running SCSI traffic over it. Be sure to use a quality managed enterprise class networking equipment. It is not recommended to use SBHO (small business/home office) class equipment outside of lab/test environments.

· Verify optimal MTU for replications. Default is 1500 but sometimes WAN circuits or VPNs can create additional overhead which can cause packet fragmentation. This fragmentation can suboptimal performance. The MTU is adjustable via the GUI in 5.x Storage Center Firmware.

For Jumbo Frame Support

· Some switches have limited buffer sizes and can only support Flow Control or Jumbo Frames, but not both at the same time. Compellent strongly recommends choosing Flow Control.

· All devices connected through iSCSI need to support 9k jumbo frames.

· All devices used to connect iSCSI devices need to support it.

o This means every switch, router, WAN Accelerator and any other network device that will handle iSCSI traffic needs to support 9k Jumbo Frames.

· If the customer is not 100% positive that every device in their iSCSI network supports 9k Jumbo Frames, then they should NOT turn on Jumbo Frames.

· QLogic 4010 series cards (Early Compellent iSCSI Cards) do not support Jumbo Frames.

o In the Storage Center GUI default screen, expand the tree in the following order Controllers->SN#(for the controller)->IO Cards->iSCSI->Highlight the port and the general tab should list the model number in the description.

· Because devices on both sides (server and SAN) need Jumbo Frames enabled, the change to enable to disable Jumbo Frames is recommended during a maintenance window. If servers have it enabled first, the Storage Center will not understand their packets. If Storage Center enables it first, servers will not understand its packets.

Also feel free to go to the link below and on the bottom of pg 169 and continueing on pg 170 it shows how to change the MTU as well.

support.dell.com/.../SC_User.pdf

I hope this helps please let me know if there is anything else I can assist you with.