Describing the Lightning as the undisputed leader in high-end RAID systems, Hitachi said it has doubled the maximum capacity of the device and the maximum number of ports the array can support. That takes the usable RAID 5 capacity of the machine to 128TB, which according to Hitachi is ideal for consolidating many disk arrays based on ageing shared bus architectures.

There is only one architecture that Hitachi’s wholly owned storage subsidiary HDS had in mind when it made that claim, and it is the venerable bus architecture of the Symmetrix. Disk array performance varies according to application and is not at all simple to judge, but for some while the Symmetrix has been considered by analysts to be in general slower than both the Lightning, and the only other high-end storage array on the market, IBM Corp’s Shark ESS.

Next week a new, sixth generation of Symmetrix will be launched. This week EMC described Hitachi’s announcement as a pre-me too. Despite EMC’s sealed lips on the subject so far, the revamp to the Symmetrix is universally expected to see the Symmetrix buses retired to the garage in favour of a switched backplane – the same as has been in use in Hitachi’s Lightning for about the last two years.

The upgrade to its Lightning 9900V will accelerate its [Hitachi’s] technology leadership over the competition, according to one Wall Street bank quoted by Hitachi in this week’s announcement. But the doubling of the Lightning’s capacity has been achieved only by offering as an option the latest 146GB disk drives which are already available for IBM Corp’s high-end Shark arrays, and which will be announced for the Symmetrix next week. Although the number of Fibre Channel ports and FICON channels on the Lightning has been doubled to 64 and 32 respectively, the internal throughput of the machine is unchanged.

The increase in the number of ports makes it easier to replace smaller, older disk arrays based on ageing shared bus architectures with a single huge-capacity Lightning. Because that process involves linking the new storage array to a lot of servers that previously were serviced by multiple arrays, the new array needs a lot of ports. You could do it with a switch instead, but doing it by using more ports on the array helps justify a consolidation, said Randy Kerns, senior partner at storage consultant the Evaluator Group.

Consolidation is a growing practice in data centers, because it lowers operating costs by reducing the number of boxes that IT staff must manage. But only a very few customers need the huge capacities offered by the biggest storage arrays fitted with the biggest disk drives. Hitachi said this week that its Lightning 9980V is on average fitted with 20TB of capacity. Kerns said: If you look at what 90% of customers are doing, 128TB is well beyond what they need, even though it is useful for that last 10% of users.

Hitachi also highlighted the ability of multiple servers to share ports when accessing V series Lightnings. Kerns said however that Hitachi has been shipping this feature for a long while – as have EMC and IBM, he said.

Source: Computerwire