On: Why Is Storage on Kubernetes So Hard?

[lostmyoldone]

From a database perspective, 1ms to disk is an eternity.

A good disk subsystem had less write latency than that in the early 90’s.

[wora → lostmyoldone]

Write to disk has no practical latency because of write buffer, either local file system or remote database. Flush to disk would be slow unless you use SSD.

On the other hand, a single machine has limited reliability. If one wants to have high availability, they needs to dual write to another machine, which also has network latency.

[emanlin → lostmyoldone]

I don’t think that’s true. I recall ~5ms seek times being top of the line.

[cat199 → emanlin]

he said 'subsystem' not 'disk'-

what was the latency to the controller with ram cache?

using seek time as a measure is also somewhat worst case - controllers/filesystems also queue(d) according to drive geometry.