> The nearly 3× increase in firesystem capacity the authors report might be worth a significant amount of software work? They aren't claiming 2.94x capacity in

> The nearly 3× increase in firesystem capacity the authors report might be worth a significant amount of software work? They aren't claiming 2.94x capacity increase, they are claiming 2.94x endurance. Per the paper's claims, drives tend to have about 11% over-provisioning. Assuming compression is not introduced concurrently, the maximum increase in capacity would be 11%. > A Samsung Evo 970 1TB SSD over NVMe PCIe3 can peak at 100k iops and 6.5 GB/s (personal communication) I think you need to check the 6.5 GB/s. A Samsung 970 Evo is a PCIe Gen 3 x 4 device with peak read throughput of 3.4 GB/s [1]. Even with a faster controller and/or NAND, PCIe Gen 3 x 4 will limit the throughput to 3.938 GB/s [2]. You may be able to get combined read+write performance in excess of 4 GB/s, but I wouldn't count on it. Perhaps instead of a 970 Evo you meant a 980 Pro, which is capable of closer to 1 million IOPS and 7 GB/s. Also, you should not assume that the same workload that can generate the maximum number of IOPS is the same one that can generate the maximum throughput. Most commonly IOPS are measured with something like 4 KiB blocks with queue depth 32 and perhaps multiple threads. Maximum throughput is generally achieved with 128 KiB or larger sequential IO with a lower queue depth and/or threads. > But writes are an order of magnitude slower (100 μs instead of 10 μs) In all of the NVMe datasheets that I've read that provide sufficient detail (i.e. not the consumer drives), writes are generally faster than reads. This is implied by [1] by the fact that it supports 15000 read IOPS and 50000 write IOPS at QD1 with one thread. I think a key reason that writes tend to be faster is because they are written to RAM and written back to NAND (perhaps with better packing) as the drive has spare cycles and/or RAM fills. This brings up the importance of power loss protection, which is generally not found on client drives like the 970 Evo or 980 Pro. 1. https://semiconductor.samsung.com/resources/data-sheet/Samsung-NVMe-SSD-970-EVO-Data-Sheet_Rev.1.0.pdf https://semiconductor.samsung.com/resources/data-sheet/Samsu... 2. https://en.wikipedia.org/wiki/PCI_Express#History_and_revisions https://en.wikipedia.org/wiki/PCI_Express#History_and_revisi...