Minor update:
Barely had time to focus on the project last week. Mostly did the storage inventory and looked at upgrade options.
I believe an understated metric, when computing $/TB is the upkeep cost of older and smaller drives. A 1TB 3.5" HDD can consume even ~7W when idle, which sums up to 168Wh per day per TB when idle. This is 5.124kWh per month per TB. Assuming 28.3 c€/kWh this amounts to 1.45 €/TB/month. Not that much, but with 12TB EXOS X14 the idle consumption is 5.4 W which amounts to 3.953kWh/mo and 1,11 €/month, but 0.09 €/TB/month.
For perspective I compared raw prices of used 1TB and 12TB drives at local resellers. A refurb ST12000NM0538 (12TB EXOS X14) can be found for 142€ which is 11.83€/TB. The cheapest 1TB Seagate drive I could find was ST1000NM0023 (Constellation ES.3 with a 4.45W at idle which amounts to only 0.92 €/TB/month) for ~11.23€ (/TB). So even at 1 month, the total difference is 11.92€ (12TB X14) vs 12.15€ (1TB ES.3). At one year the difference is 12.91 vs 22.27, which means in one year you’re paying almost double for smaller, older drives. This does not include costs of replacing upon failure.
While researching this I was actually surprised at the idle power consumptions of various drives. E.g. ST8000NM003B has idle power rating of 7.24W (SAS, for SATA it’s 7.06W) vs 5.3W of HUH728080ALE600, both 8TB drives, with SG being noticeably newer (2021 vs 2016 I believe). At the same time there are the X14 drives with sub-5W idle power. Another interesting datapoint is HDWG21CUZSVA/HDWG11AUZSVA/HDWG480UZSVA where for 12TB/10TB/8TB models idle power is 4.28W/7.22W/5.61W respectively; and you can easily see that the 10TB variant must be built differently, because it’s one of a kind here (higher mass, higher acoustics, different temp ratings…)
On the software side, I’m trying to figure out inter-vm networking on Xen, but the more I research, the more sceptical I am.