HP P6300 HP P6300/P6500 EVA Installation Guide (5697-2485, September 2013) - Page 8

Table 1 Minimum recommended switch capabilities for a P63x0/P65x0 EVA-based IP-SAN (continued) Switch capability Description cache among a group of ports (for example, 1 MB of cache per 8 ports), space your used ports appropriately to avoid cache oversubscription. Flow control support IP storage networks are unique in the amount of sustained bandwidth that is required to maintain adequate performance levels under heavy workloads. Gigabit Ethernet flow control (802.3x) technology should be enabled on the switch to eliminate receive and/or transmit buffer cache pressure. NOTE: Some switch manufacturers do not recommend configuring flow control when using jumbo frames, or jumbo frames with flow control. Consult the switch manufacturer documentation for guidance on this issue. HP recommends implementing flow control over jumbo frames for optimal performance. Flow control is required when using the HP DSM and MPIO. Individual port speed and duplex setting Link aggregation/trunking support All ports on the switch, servers, and storage nodes should be configured to auto-negotiate duplex and speed settings. Although most switches and NICs will auto negotiate the optimal performance setting, if a single port on the IP storage network negotiates a sub-optimal (100 megabit or less and/or half-duplex) setting, the entire SAN performance can be impacted negatively. Check each switch and NIC port to make sure the auto-negotiation is resolved to be 1000 Mb/s or 10 Gb/s with full-duplex. Link aggregation and/or trunking support is important to enable when building a high performance fault-tolerant IP storage network. HP recommends implementing link aggregation and/or trunking technology when doing switch-to-switch trunking, server NIC load balancing, and server NIC link aggregation (802.3ad). VLAN support Implementing a separate subnet or VLAN for the IP storage network is a best IP-SAN practice. If implementing VLAN technology within the switch infrastructure, you typically need to enable VLAN tagging (802.1q) and/or VLAN trunking (802.1q or InterSwitch Link [ISL] from Cisco). Consult your switch manufacturer configuration guidelines when enabling VLAN support. Spanning tree/rapid spanning tree In order to build a fault-tolerant IP storage network, multiple switches are typically connected into a single Layer 2 (OSI Model) broadcast domain using multiple interconnects. In order to avoid Layer 2 loops, the Spanning Tree protocol (802.1D) or Rapid Spanning Tree protocol (802.1w) must be implemented in the switch infrastructure. Failing to do so can cause numerous issues on the IP storage networks, including performance degradation or even traffic storms. HP recommends implementing rapid spanning tree if the switch infrastructure supports it for faster spanning tree convergence. If the switch is capable, consider disabling spanning tree on the server switch ports so that they do not participate in the spanning tree convergence protocol timings. NOTE: FCoE should be configured with spanning-tree disabled at the first level server edge switch. Jumbo frame support Sequential read and write, or streaming workloads, can benefit from a larger maximum frame size than 1514 bytes. The iSCSI and iSCSI/FCoE modules are capable of frame sizes up to 9 Kbytes. Better performance is realized when the NICs and iSCSI initiators are configured for 4 Kbyte (maximum frame size of 4088 bytes) jumbo frames. Jumbo frames must be enabled on the switch, the iSCSI and iSCSI/FCoE modules, and all servers connected to the IP-SAN. Typically, jumbo frames are enabled globally on the switch or per VLAN and on a per port basis on the server. NOTE: Some switch manufacturers do not recommend configuring jumbo frames when using flow control, or flow control with jumbo frames. Consult the switch manufacturer documentation for guidance on this issue. HP recommends implementing flow control over jumbo frames for optimal performance. 8 Reviewing and confirming your plans