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IO Devices and Latency

planetscale.com

21–30 of 159 posts

Re: IO Devices and Latency

#21
post #3

Author of the blog here. I had a great time writing this. By far the most complex article I've ever put together, with literally thousands of lines of js to build out these interactive visuals. I hope everyone enjoys.

Hi, what actually are _metal_ instances that are being used when you're on EC2 that have local NVME attached? Last time I looked, apart from the smallest/slowest Graviton, you have to spend circa 2.3k USD/mo to get a bare-metal instance from AWS - https://blog.alexellis.io/how-to-run-firecracker-without-kvm...

Hi there, PS employee here. In AWS, the instance types backing our Metal class are currently in the following families: r6id, i4i, i3en and i7ie. We're deploying across multiple clouds, and our "Metal" product designation has no direct link to Amazon's bare-metal offerings.

Re: IO Devices and Latency

#26
post #18

I've been advocating for SQLite+NVMe for a while now. For me it is a new kind of pattern you can apply to get much further into trouble than usual. In some cases, you might actually make it out to the other side without needing to scale horizontally. Latency is king in all performance matters. Especially in those where items must be processed serially. Running SQLite on NVMe provides a latency advantage that no other…

I still measure 1-2ms of latency with an NVMe disk on my Desktop computer, doing fsync() on a file on a ext4 filesystem.

Update: about 800us on a more modern system.

Re: IO Devices and Latency

#29
Hrm "unlimited IOPS"? I suppose contrasted against the abysmal IOPS available to Cloud block devs. A good modern NVMe enterprise drive is specced for (order of magnitude) 10^6 to 10^7 IOPS. If you can saturate that from database code, then you've got some interesting problems, but it's definitely not unlimited.

Re: IO Devices and Latency

#30
post #27

Can someeone share their expirience in creating such diagrams. What libraries and tools can be useful for such interactive diagrams?

For this particular one I used d3.js, but honestly this isn't really the type of thing it's designed for. I've also used GSAP for this type of thing on this article I wrote about database sharding.

https://planetscale.com/blog/database-sharding

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