[theden]

This is great, the visual explanations work really well

One thing that threw me off is that it says for an SSD a random read is 150μs, but 1MB sequential read is 1ms? Shouldn't sequential reads be faster, or are two different read sizes being compared or something? If so, the ambiguity may confuse some people to think random reads are faster

[sharikous]

My interpretation is that 150us is the minimum latency no matter what for any size, since the seek time is provided for comparison for HDs

[darkcha0s]

Well I'm guessing that it's referring to the fact that 1MB sequential is essentially a bunch of random reads?

AFAIK, on SSD's there is no concept/guarantee that blocks are adjacent, so a sequential read is just a bunch of random reads.

[jasonwatkinspdx]

The way the Flash Translation Layer works is complicated, but long story short, there's still an advantage to sequential reads and writes on SSDs. The difference in latency and throughput isn't as dramatic as with spinning disks, but is still there. Random vs sequential writes have big implications for the long term health and performance of the SSD.