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The motivation for VMWare VSAN 5.5 stemmed from our limited experience with off the shelf products, our budget, and our existing infrastructure.

First I have to clear the air. Our first experience with any SAN technology was with a Drobo 1200i. This device cost us around $12k at the time and we didn't have very much storage experience, so we were kind of in the dark as to what we needed, what kind of performance we would get, and where to put our money. Well, we quickly learned that this device was not as great as was advertised. The sales folks at Drobo convinced us that we could "run active vm's" on the device and ultimately I dreamed of using this common datastore to enable VMWare features such as High Availability (HA) and Fault Tolerance (FT). No such luck.

The Drobo 1200i, at the time, came with 6 HDD's, with capacity for up to 12 HDD's total, we configured our's with 9 HDD's at 2TB each. Later, they updated their firmware for automated tiering with SSD's, which undoubtedly would have increased performance, but it was too late for us to sink any more money into these devices.

The 1200i is equipped with 4 ethernet ports, 3 for iscsi over ethernet connections, and 1 management port. In our configuration, we wired up a Ciscso SG 300-20 20 Port Gigabit managed switch to the 3 iscsi ports on the drobo, and each VMWare host also had two 1-gb nic's connected to the switch. Everything worked well and all the VMWare hosts were able to mount partitions on the Drobo. After that, I started to play around with moving some of the VM's to this datastore. The performance was abysmal, and so we abandoned the idea of running VM's from the drobo and used it primarily for backups.

We had a lot of issues with the Drobo 1200i. Some mis-configurations would cause the device to reboot continuously, requiring a patch from the vendor to remove bad volumes, this sometimes took weeks. The proprietary software doesn't leave much room for the end user to troubleshoot, so you pretty much have to call support anytime anything goes wrong.

Our solution worked well for many years. We treated the Drobo like tape, and it chugged along slowly and kept our backups on hand.

Fast forward to 2014. We were getting ready to upgrade our VMWare Infrastructure and I had heard some rumors about the VSAN product. After some serious whitepaper reading, we decided that this would be the best fit. In a lot of ways, it is akin to the next logical step up from our old Drobo setup. Only, instead of a 1-GB iscsi over ethernet, we would run an all 10GB network. And instead of a HDD device, we would have a mix of SSD's and HDD's on each VMWare Host. Now, the next step was purchasing the hardware.