My company has reached that tipping point where what we are spending on EBS storage warrants a serious look at moving our storage to a SAN/NAS in a Co-Lo location connected with AWS Direct Connect.
Pricing Co-Lo and Connectivity in this regard is straightforward, but pricing hardware is very complex at this early evaluation stage.
1TB of storage in AWS EBS costs $1,200 per annum ($0.10 per GB per month).
In the order of 300TB, and assuming 3 year depreciation, is it reasonable to think we can get Co-Lo SAN/NAS for < $3,600 per TB?
We don't need All-Flash. IOPS requirement would be about 2k IOPS IN+OUT.
This is totally doable. However, don't forget that apart from SAN hardware/software itself, there are lots of things that should be considered, such as: redundant power supplies, redundant WAN/LAN, IT staff onsite who will manage your infrastructure, etc..
First off, define how much downtime costs for you company and determine your RTO/RPO. This is a business question that should be addressed to your bosses. Finally, it would be much easier for you to spec-out a proper hardware/software when you know all the details.
well it is hard say what the on premise storage costs are in your case, because it is not only the hardware. Also the hardware costs depends on the offer you get. But if there are no high IOPS needed, why you don´t use S3 with riofs? With riofs you can mount a S3 bucket directly on you EC2. https://github.com/skoobe/riofs
In S3 your 300TB will be ~$90.000 p.a. which means ~$300 per TB/p.a (in Frankfurt region)
Maybe thats an alternative for you?