3 ms·

Thanks for the link. How does this compare to the analogous situation for SSD access? I know there are also userspace IO stacks for similar reasons, but it seem

Thanks for the link. How does this compare to the analogous situation for SSD access? I know there are also userspace IO stacks for similar reasons, but it seems like SSD-via-kernel is way ahead of network-via-kernel in the sense that it adds less latency per operation over the best userspace stack.

vitus 3y ago
I can't say offhand, since I don't have much experience with storage. I'd expect that most of the work from a SSD read is offloaded to the disk controller, which presumably uses DMA, and you don't have nearly as many round trips (a sequential read can be done with a single SCSI command). I'm inclined to agree with the explanation given by other commenters that the limiting factor for SSD r/w speeds in the cloud is due to throttling in the hypervisor to provide users with predictable performance as well as isolation in a multitenant environment.