hmm.. interesting.. specifically +Robert Scoble
's mention of Skyera's 1U flash storage unit. Though checking their site, its not really 1/4 Peta (250TB) but rather 44TB (http://skyera.com/news-events/press-releases/skyera-unveils-skyhawk/
). Still, impressive nontheless. compared to the most efficient use of space I've seen so far is (actually was, as this model doesn't exist from that vendor anymore) Nexsan's 1U unit with 8 3.5" HDDs which could (today) get to 4*8=32TB. There is also the 1U flash unit from RamSan, which was sold bought by IBM..
one MAJOR problem with the flash storage units is... price. Looking at Skyera's announcement.. $3 per Gig, we are talking about $135,000!!! per unit!!! That is not a manageable price for anyone I know who is in anyway price conscience. In comparison to magnetic media, the same storage space would cost about nearly 5-10% of that of a flash solution.
AND... if you don't insist on 1U, NEXSAN, HP and other companies have actually far greater storage density than flash solutions.
For example, NEXSAN's specs of their 4U unit shows it can hold up to 60! disks of 4TB each. that is 15 disks per 1U. This is a ridiculously high capacity and density. Think about it! 60TB per 1U or 240TB per 4U. and all those units allow integration of SSD disks as part of their architecture and design, so random writes are done to SSD while offloaded then to magnetic disks in the background. SUN (now Oracle) also has interesting solutions in storage. For me, having been on the consumer side and personally feeling the pains of storage limits, storage and its new capabilities with new technologies and capacities is an highly exciting field.