Here’s the story to how the infamous “Edsai” and banana bread thing came to be. Back in April, Vaughn Stewart of Netapp posted a blog entry about “blogging with integrity” that went right after Chad Sakac. It created a bit of tension that frustrated a lot of people. Instead of going negative I asked myself what would diffuse the tension. I get this kick-ass toffee banana bread delivered weekly from FarmFreshDelivery.com that tastes so good when you warm it up and have it with a glass of milk. I tweeted “@vStewed have some banana bread. and some milk. it shortens the lengthy blog posts. for me it does anyway.” I decided I’d ship some out to Vaughn and anyone else who wanted some.
I received a number of replies and ended up shipping about 12 loaves across the country. Actually, my wife did and I’m indebted to her for it as she’s done it on another two occasions. I know I accomplished my goal because a number of people messaged me and told me they appreciated me breaking the tension. Now I just do it because people love the banana bread.
I thought I’d give the back story because references to “Banana Bread” have found their way into EMC team training presentations, rap videos and other crazy places.
Simon Seagrave (http://www.techhead.co.uk/) asked, “How long do you think it’ll be before SSD will overtake SCSI as primary tier 1 SAN storage? Giving a new SSD and SATA tiered mix.”
Short answer: Yes, it will be SSDs + SAS and within 2 years.
The real quesion is when 15K RPM highspeed drives will be replaced with SSDs and 7.2K RPM high capacity drives. SAS will probably end up replacing both FC and SATA in the majority of mid-range storage but the jury is still out on if this will happen in high-end arrays.
What are we talking about here? From an array design perspective, frequently accessed blocks of data should be served from ram and SSD. SSDs have a much faster response time (microseconds vs. milliseconds) than traditional hard disk drives which enable this possibility. The Sun Unified Storage platform was one of the first platforms to do this all in one array with their Hybrid Storage Pool design. There are also some new appliances coming out like the Xcelasan from Dataram. NetApp offers read accelerationt through their PAM 1 (Performance Acceleration Modules). EMC will also start the transition at the LUN level with their implementation of FAST as described by Devang Panchigar. This list is not meant to be comprehensive as I’m sure I have left out vendors and their roadmaps.
When will this happen? I expect the majority of storage vendors to implement this type of solution at the block level within the next 2 years based on current development cycles from most major storage vendors. It will take some longer than others because of their architectures. It will be a key differentiating feature between vendors. Beyond basic tiering between SSDs and high capacity disks we should see more advanced algorithms on what data and where to move it to. I’ve followed journey of Sun’s ZFS on the zfs-discuss mailing lists over the last year and have noticed that peculiar performance behaviors happen (write-pulsing) have required fine-tuning.