Random IO while plotting

Hello, it appears that the plotting process is heavy on random IO, which HDD do not support well at all.

Attached you see a picture of a plot running on a RAID-0 of 4x SATA SSD. Each SATA SSD can provide several hundred MiB/s if writes are sequential. That each SSD only contributes about 50 MiB/s during plotting, makes me conclude this is heavy on random IO. The system runs with 32 G of DDR4-4000 and 12900k 16 core, 24 threads. Should provide enough compute.

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@ivan-subspace Can you speak to the random IO here?

This isn’t a great mystery. Trying to plot to HDD is currently a waste of time.

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Currently, initial plotting after some moment will rely on random IO and will be slow on HDD. You are totally right.

We hope to fix that soon so that it would utilize more sequential reads and write.