Something that's interested me is how hard drive capacities have continuously gone up, but read and write speeds have not really changed. To the point where it would take multiple days to read these new high capacity drives.
I wonder what the use case for them is, they aren't ideal for RAID as they would take far too long to rebuild the array in a drive failure, but they also aren't great for long term cold storage. Perhaps they are ideal for periodic backups where you want to take a daily 1TB backup of a server or CCTV where you don't really care about backing up the data as it's all deleted on schedule anyway.
Speeds do go up with density. Take an empty 4 TB drive and an empty 16 TB drive, and then write and read 2 TB of data to both of them. Since the platters on the 16 TB one are that much denser, you go over a lot more blocks in a single spin than the 4 TB one.
That's a very logical theory, but it doesn't really seem to hold up in real-world data transfer speeds.
For instance: 7200 RPM SATA drives have been stuck in the peak-performance realm of between about 250 and 300 megabytes per second for a decade, even though maximum capacity has more than tripled over that time.
The 16 TB drive won't be anywhere close to 4x faster than the 4 TB drive, though. Maybe 20% (~200 MB/s vs ~230-250 MB/s). That's because most of the capacity increase comes from more tracks and more platters, not linear density, which determines throughput.
I would say 250-260MB/s for a 16TB drive, and when 4TB drives were newer they were more like 160-180MB/s. That's about a 50% increase.
Doing the math, you're probably going from 5 to 8-9 platters, so 2.2-2.5 areal density, and a naive square root suggests it should be about 50% faster. So maybe track width is taking a fair share after all?
Though when I look at more sizes, it seems like 12TB drives were also hitting 260MB/s and speed has almost entirely stalled since, with 24TB being only a hair faster.
Gigachad · · focus · HN ↗
I wonder what the use case for them is, they aren't ideal for RAID as they would take far too long to rebuild the array in a drive failure, but they also aren't great for long term cold storage. Perhaps they are ideal for periodic backups where you want to take a daily 1TB backup of a server or CCTV where you don't really care about backing up the data as it's all deleted on schedule anyway.
Hamuko · · focus · HN ↗
ssl-3 · · focus · HN ↗
For instance: 7200 RPM SATA drives have been stuck in the peak-performance realm of between about 250 and 300 megabytes per second for a decade, even though maximum capacity has more than tripled over that time.
formerly_proven · · focus · HN ↗
Dylan16807 · · focus · HN ↗
Doing the math, you're probably going from 5 to 8-9 platters, so 2.2-2.5 areal density, and a naive square root suggests it should be about 50% faster. So maybe track width is taking a fair share after all?
Though when I look at more sizes, it seems like 12TB drives were also hitting 260MB/s and speed has almost entirely stalled since, with 24TB being only a hair faster.