1955 blades to use 2.5" SAS only?

[Andrew Mann]

    This is based on second or third hand information, and AFAIK the 
specs on the 1955s haven't been officially announced yet, but I figure 
early discussion is better than late.

    My understanding is that the 1955 blades will use 2 x 2.5 " SAS 
drives as the only drive configuration option.  Is there an advantage to 
this configuration over the 2 x 3.5" drive configuration of the 1855s?

    One of the price advantage points touted a year or two ago when the 
1855 blade chassis was debuted by dell was that the blade units were 
using 3.5" drives, which are cheaper and can accommodate larger storage 
capacity than 2.5" drives. Since the blades will still only house 2 
drives, and the SAS/SATA interconnect should have, if anything, reduced 
the physical requirements for the drive bays, I'm having trouble seeing 
a reason for the switch.

    I can see some justification for the 2950s to allow 2.5" drive bays 
(maybe you really need to bump from 6 to 8 units for raid performance), 
and I could see the reason if the 1955s were to allow 3 x 2.5" drives, 
but with just 2 the change from a purchasing point of view seems like a 
pretty hefty price hike, a decrease in capacity options, and no apparent 
advantage.

Andrew