When a server blade is inserted, the mid-plane routes its network connections through to different switch blades at the rear. The chassis provides eight slots and you have a wide range of modules to choose from which includes 16-port pass-through modules and Gigabit switches - it’s worth noting that Cisco was given the task of designing them for the c-Class chassis. Gigabit over fibre is supported by modules which have eight fixed copper ports along with four mini-GBICs that accept SX, LX and long-distance LH fibre optic SFPs. Fibre channel SANs also get a look in as HP offers 12- and 24-port Brocade FC SAN switches as well. The chassis also accommodates HP’s very latest VC (virtual connect) module which comes with a pair of 10GbE CX-4 copper ports. This comes into its own for server redundancy as a failed server in one chassis can be replaced by a hot-standby server in another linked chassis and its MAC addresses will be passed across to the standby server as well.
The majority of enterprises will have tough security measures and full change management procedures in place so support staff can’t just swap blades without authorisation. HP has this covered as it provides virtual pools of MAC addresses that can be assigned to new blades when they are first installed. The pool is created and registered securely for the customer by HP and the process aims to accelerate hardware upgrades and new server deployments. HP also has initial integration with FC SANs covered as it offers a virtual connect module with a pool of unique WWNs.
Power is very well handled as a module at the back has room for six inputs which are routed through to hot-plug power supplies. These are accessible from the front below the blade slots and fault tolerance is so good that the blades will continue to function with three failed supplies. HP’s design flair even extends to cooling as the chassis has room for up ten hot-swap fan modules. The server blades have no cooling fans themselves allowing the chassis to handle this function. To improve air flow and reduce noise levels HP turned to jet engine design so each module uses a metal bladed fan that is shaped more like a turbine. Slots without fans installed are closed off with louvres and the chassis has thermal sensors fitted allowing it control the speed of each module. The fans aren’t dedicated to any particular component so air flow from all installed modules is spread equally across the chassis allowing it to tolerate failures.