By DELL-Jeff Junker 03 Sep 2009 8:00 AM

Working in a development and testing lab environment with many generations of gear can present some interesting opportunities to produce your own reality TV show. Here is an episode of LAB TV… well a mini-episode anyway...

So a few months ago as a relative newbie to EqualLogic, I was tasked with building out some testing environments using all the various Dell gear: blade servers, rack servers, switches, power distribution and, of course, EqualLogic storage.

The gear I was given was of widely varying vintage, and quite colorful as well, given that EqualLogic controllers have different color rear sticker bezels for different generations of controllers. Five racks later, where I could find holes of space, and after several test benchmarks on Exchange using VMware and HyperV focused systems were done, I noticed some additional older gear in a nearby rack that was not currently being used. That was the kernel of the idea. It turned out that we had all versions of the EqualLogic PS series created to that point within arms reach -- from the first PS100 series units, PS200 / PS400 Series, PS3000, PS5000 generation controllers through the PS6000XV and PS6000S (SSD) as well as the “SUMO” PS5500/6500 48 drive chassis. Back to the idea. Why not connect all seven generations of hardware together and create an iSCSI SAN spanning all these generations and technologies -- might make for a cool story.

Here's what happend next ... I connected all the units together on same switch fabric and updated the firmware on all the arrays to the current shipping version. All together there were 12 arrays, with seven generations of controller technology, all running the same firmware, and upgraded to same feature set, presenting four pools of virtualized storage, on the same SAN. Once all the units were connected to the switch and at the same firmware level – even the first generation array inherited all the current features, raid level options, replication tools, VSS integration and MPIO load balancing capabilities -- the full suite of current EqualLogic software on all generations of gear, so logically they were all “peers” in feature capability.

Here are two screen shots that show the 12 arrays configured and an intermediate step where volumes are being live migrated between pools – transparent to user with no downtime:

eql_migrate2sas


12arrays1


In the Group Manager GUI – there is a controller type and boot firmware date – with earliest Series 100/200 array from 2004 boot ROM and Type “1” controller which is cleverly gray, to the type 7 and not quite fluorescent green. Most of the rainbow is in between for the other controller generations, with the latest PS4000 just released with glow in the dark pink (or rose or purple – but that that is another discussion of what color it really is) looking to do this test again with 10G Ethernet mixed in and with PS4000 which arrived just after this testing was done (drat).

quadfather PS6K green


So the reality TV part – is the PS Series stands for “Peer Storage” and that is true not only for like model units, but also across generations of controller technology, drive types (SATA, SSD, SAS 10K+15K), size of array shelves (16 and 48 drive cabinets) and RAID levels, eliminating forced forklift upgrades when the next generation of technology is released. Everyone everyone take a deep breath -- and relax! The end result is as new generations of gear come out, you can add Member arrays to your existing SAN to expand and take advantage of new technologies (SSD for example) or new drive sizes (600GB 10K or 15K drives or 2TB SATA are also recent examples). Since each PS series member has the controller intelligence built in, as well as additional Gigabit Ethernet ports, you expand not only the drive capacity / performance, but also expands networking bandwidth. So after even the short time I have been here, one gets desensitized to the coolness of this multi generational mix and match capability with near linear scaling, but when you see the reactions of people seeing it for the first time or better proving it to themselves, that is like the “priceless” commercials. Just nod your head and smile…


7 Generations iSCSI SAN front7 Generation iSCSI SAN in process


After this was built, I showed a few management types at Dell who thought it was cool too and asked ESG team to come in and take it for a test drive with a Total Cost of Ownership perspective since being able to expand your SAN over time and not do fork lift upgrades has many dimensional benefits. In fact, ESG (Enterprise Strategy Group) wrote a white paper based on their experience with 7 generations of EqualLogic iSCSI SAN. Clik on blue text link to download TCO white paper. Video Link is below.