180 TB is using 4 TB drives. 270 TB is using 6 TB drives. Backblaze uses 4 TB drives because of the increased costs and failure rates of the 6 TB drives. htt

180 TB is using 4 TB drives. 270 TB is using 6 TB drives. Backblaze uses 4 TB drives because of the increased costs and failure rates of the 6 TB drives. https://www.backblaze.com/blog/wp-content/uploads/2015/03/blog-storage-pod-cost-chart1.jpg https://www.backblaze.com/blog/wp-content/uploads/2015/03/bl... (270 TB * 1000 GB/TB * .051 $/GB = $13770 ) My original estimate of $20,000 was just a rough estimate that added some padding for overhead and accessories.