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For server blade storage, HP prefers you to use SAS with the half-height DL460c, for example, supporting a pair of low-profile 2.5in hard disks in hot-swap carriers. All its blades offer RAID as standard and come with an embedded Smart Array controller and cache memory and the latter can be upgraded and protected with an optional battery backup pack. There’s even room to expand as the half-height blades have a pair of PCI-e slots that accept Gigabit Ethernet or fibre channel cards.
Each blade has a pair of embedded Gigabit Ethernet adapters and HP scores highly here as these incorporate not only a TOE (TCP offload engine) but even hardware iSCSI initiators allowing them to join an IP SAN. The latest blades also have integrated USB ports on their motherboards allowing internal USB security dongles to be installed or used to boot servers from flash memory.
Naturally, the full height blades have a lot more potential and all provide four hot-swap 2.5in. hard disks bays with support for RAID-5 as well as mirrors and stripes. It’s not so valuable with only four drives to play with but the Smart Array controllers also offer RAID-6 which requires a minimum of four drives to function but can survive the loss of two. The network connections are doubled up as well as these blades provide four Gigabit Ethernet ports. Network port count can also be increased on the half-height blades with the new quad Gigabit mezzanine card which is aimed primarily at server virtualisation environments. As with its ProLiant servers, all server blades incorporate an embedded iLO2 management controller allowing them to be remotely monitored and managed from HP’s Insight Manager software.
The storage picture looks even brighter as HP recently introduced the SB40c blade which can provide direct attached storage to the servers. It has room for up to six hot-swap SAS or SATA drives and combines HP’s P400 Smart Array controller along with a 256MB cache and battery backup pack as standard. There are some limitations as a single storage blade integrates directly with the server blade to its left and the full-height blades require an additional PCI-e mezzanine card installed. Furthermore, although the midplane is used to link the storage blade with the server this employs a PCI-e interconnect so hot-plug is not currently supported.