Agreed: 80MB/s for the random 8K page updates. However, transaction logs in modern databases are committed to disk in batches, and each log entry is smaller than a page size. So a nice round number would be 100 MB/s for both.[1]
For comparison, that's about 1 gigabit per second in the era of 200 Gbps networking becoming common. That's a small fraction of SSD write throughput of any modern device, mobile or not. Nobody in their right mind would use HDD storage if scaling was in any way a concern.
[1] Indexes add some overhead to this, obviously, but tend to be smaller than the underlying tables.
For comparison, that's about 1 gigabit per second in the era of 200 Gbps networking becoming common. That's a small fraction of SSD write throughput of any modern device, mobile or not. Nobody in their right mind would use HDD storage if scaling was in any way a concern.
[1] Indexes add some overhead to this, obviously, but tend to be smaller than the underlying tables.