By Craig Simpson

EMC's Chuck Hollis recently posted quite a blog stream on storage capacity efficiency.  His latest post concluded "it's time to step back a bit from the fray."  It is quite a fray.  But, my step back to look at the big picture uncovered some different thoughts from Chuck's.  He started this with a case where a chosen interpretation of best practices could make CX look better than EVA.  Of course, if one levels the playing field by letting EMC configure the CX (like Chuck did) and HP configure the EVA they both come out around 70% efficiency.  I appreciate that EMC recognized some of our points.  Here’s the rest.

However, since turnabout is fair play, I wondered if I could cook up a case to make EVA look lots better than CX.  Sure enough.  Put both a performance intensive workload (3000 IOPS, 1TB) and a non-performance intensive workload (300 IOPS, 1TB) on the array.  The performance intensive workload uses RAID1 while the other uses RAID 5.  Seems a reasonable mix of uses for an array. The EVA uses 30 disks compared to CX’s 41 making it 37% more efficient because CX can’t have RAID 1 and RAID 5 in the same RAID set.  Now EMC could open the arguments about how their workload is better or I’m misusing their array or …

But the point is that anybody can find a way to make their array look good.  EMC, why did you use RAID5 for “Exchange” when you recommend RAID 1?  Digging into the numbers shows it was important to making your array look good.  If you really want to show a meaningful comparison let’s agree on a third party to define and do the comparison.  Let’s make it a challenge.  Loser pays and we both put it on our websites.  I know we can get plenty of volunteers to run it.  But if you don’t, then this was just a colorful marketing show proving anybody can make their array look good.