Disclaimer: Looking with my HPC admin hat. To be able to store that amount of data on SSDs, you need tons of enterprise mixed load SSDs, and they don't come ch

Disclaimer: Looking with my HPC admin hat. To be able to store that amount of data on SSDs, you need tons of enterprise mixed load SSDs, and they don't come cheap in any sense or form. To offset costs, you add tiering with mechanical disks, with varying capacities and readiness states. Spinning up cold storage takes time and energy, and if you need a three year old CSV file summarizing your results, that's a lot of energy and time. The storage pipeline storing rest of your research might go to "sleep" again until you make sure that you gonna need rest of the dataset and everything to re-run some of the experiments. The data access pattern maybe hitting some cold paths too often as a result, so Microsoft might be trying to confine research institutions to a warmer tier, and since that tiers are more expensive to operate, they might be slashing storage space. Otherwise the resident data might poison other user's access patterns. This is not to say Microsoft is doing right, I believe the opposite, but this is why they might be doing it.