Apples and Oranges
Comments (2) Visits (15807)
On Wikibon, David Floyer has an article titled [SAS Drives Tier 1 to New Levels of Green] that focuses on the energy efficiency benefits of newer Serial-Attach SCSI (SAS) drives over older Fibre Channel (FC) drives. This makes sense, as R&D budgets have been spent on making newer technologies more "green".
Fellow blogger Hu Yoshida (HDS) encourages people to [Invest in the Future with SAS, SATA and SFF], referring to Figure 1.
Of course, people might consider this an [apples-to-oranges] comparison. Not only are we changing from FC to SAS technology, we are also changing from 3.5-inch drives to small form factor (SFF) 2.5-inch drives. It seems odd to specify 2000 drives, when only two of the five scale up to that level. Few systems in production, from any vendor, have more than 1000 drives, so it would have seemed that would have been a fairer comparison.
However, Hu's conclusion that the combination of SAS and SFF provides better performance and energy efficiency for both IBM DS8800 and HDS VSP than FC-based alternatives from any vendor seems reasonably supported by the data.
Meanwhile, fellow blogger David Merrill (HDS) pokes fun at IBM DS8800 in Figure 2 in his post [Winner o’ the green]. This second comparison was for 4PB of raw capacity, which 4 of the 5 can handle easily using 2TB SATA drives, but the DS8800 is based on SAS technology and does not support 2TB SATA drives. A perf
The main take-away here is that IBM offers both the DS8700 for capacity-optimized workloads, and the DS8800 for perf