Comment Simon Brassington, strategist at HP StorageWorks UK & Ireland, took issue with our reporting of HP's new P9500 array. This is based on Hitachi's VSP, technology, and using solid state drives and 2.5-inch but not 3.5-inch disk drives.
He said: "Your impression of the HDS system is a 'solid and effective refresh of HDS' top-end storage product' while the P9500 review concludes with 'cannot replace the (XP 24000)', is unfortunate given that they are based on essentially the same hardware. Also, your description of 'slapping a label' on the VSP doesn’t do justice to the collaborative partnership that HP and HDS have enjoyed in developing these products over the last 12 years."
Brassington then said: "the key difference between the two systems’ hardware is that HDS have decided to use the larger format drives. But the key success factors of the current XP array is that it is a bullet-proof (literally), high performance storage array - regardless of the drive capacities. In that case, to give the newly launched P9500 the feedback you have put forth based on the drive size difference is rather unfair in our view, particularly when it offers 1.5X greater performance."
Er, not quite; we did point out: "HP says this means the P9500 has 'double the power efficiency and I/O per square foot in half the space' compared to competitive 3.5-inch disk drive arrays and the XP24000."
Regarding the decision not to use 3.5-inch hard drives he says:
The obvious benefit to using 2.5-inch disks is that they consume less power and fit a smaller footprint ... The fact that HDS has decided to offer 3.5-inch drives to their customers and HP has not, changes the internal capacity of the box, but it doesn’t change any of the feature sets or functionality. Focusing on total system capacity is misleading as most customers will never use the full capacity of the system – we have XPs out there with only 10TB of data on them...
Should anyone need to scale beyond single-system capacity they can use multiple arrays ... that doesn’t mean that we should have made it even bigger because capacity has to be balanced against the capability to get IOs in and out of the machine - the “width ways” performance.
The difference between the HDS and HP approaches that struck us is that Hitachi and HDS are using the VSP to replace their previous USP-V range. HP, which OEMs the USP-V from Hitachi as the high-end X24000 and smaller X20000, has chosen not to do this, retaining both systems with the P9500 sitting between them in capacity terms.
Implicit in Brassington's view is that HP has chosen not to follow Hitachi and HDS in retaining the 3.5-inch drive format and thus having a much higher internal capacity in the P9500. It appears that, where customers want a higher internal capacity than HP's P9500 offers, HP will propose the X24000 while Hitachi and HDS will propose their VSP with 3.5-inch disk drives, giving the customers VSP performance, like the P9500, but much higher capacity.
This point must have been considered by HP, so it presumably thinks that the role of 3.5-inch disk drives in high-end enterprise arrays is going to decline because spindle count-driven I/O, accelerated by flash drives for the most active data, plus the lower array floorspace needs and energy costs inherent with 2.5-inch drives, will put the large format drives at a disadvantage.
It implies that bulk data will not be stored inside high-end enterprise arrays, a position at odds with HItachi, which positions the VSP as a single array for storing all data types: block, file and object. Hitachi has things like its HNAS filer and HCAP archive system using the VSP as their storage device at the same time as transaction-type applications use it to hold fast access block data.
Brassington also points out that "The strong collaboration between HP and Hitachi has resulted in enhancements to the current range, such as the new user interface. HP also invests significantly in offering an enhanced customer experience through the APEX software and Smart Tiering." Indeed it does, although Smart Tiers, based on 42MB page chunks, is also available with VSP, where it is known as Dynamic Tiering. The APEX software is specific to HP.
We said the P9500 "does not have the capacity to replace or even match the XP24000." We standby that; it is true. By retaining 3.5-inch drives in its VSP Hitachi is supporting the view that internal capacity is important. more important than in HP's view. We pointed out that the P9500/VSP is a faster-performing system than the USP-V/XP24000, and don't agree our story was "unfair." ®