Wednesday, September 10, 2014

iSCSI and Ethernet

Each manufacturer of Ethernet switch may implement features unique to their specific model. Below are some general tips to look for when implementing an iSCSI network infrastructure. Each tip may or may not apply to a specific installation. Be aware that this is list is inspired by DELL Compellent iSCSI bets practices and it is not an all-inclusive list.
  • Bi-Directional Flow Control enabled for all Switch Ports that carry iSCSI traffic, including any inter switch links.
  • Separate networks or VLANs from data.
  • Separate iSCSI traffic multi-path traffic also.
  • Unicast storm control disabled on every switch that handles iSCSI traffic.
  • Multicast disabled at the switch level for any iSCSI VLANs - Multicast storm control enabled (if available) when multicast cannot disabled.
  • Broadcast disabled at the switch level for any iSCSI VLANs - Broadcast storm control enabled (if available) when broadcast cannot disabled.
  • Routing disabled between regular network and iSCSI VLANs - Use extreme caution if routing any storage traffic, performance of the network can be severely affected. This should only be done under controlled and monitored conditions.
  • Disable Spanning Tree (STP or RSTP) on ports which connect directly to end nodes (the server or Dell Compellent controller's iSCSI ports.) You can do it by enabling PortFast or EdgePort option  on these ports so that they are configured as edge ports.
  • Ensure that any switches used for iSCSI are of a non-blocking design.
  • Hard set for all switch ports and server ports for Gigabit Full Duplex if applicable.
  • 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.
Do you want configuration examples for DELL PowerConnect and DELL Force10 switches? Leave a comment with particular switch model and firmware version and I'll try my best to prepare it for you.

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