Bladebit CUDA plot suggestion

I use RTX 3090 with 24GB + KRPA-U16 mother board(PCIE 4.0) + 512 RAM + EPYC 7532 CPU.

I have a PCIE 4.0 SSD and many many 16TB HD connected with 10G fiber.
OS is windows 10 pro.

compress level is 7.

If I plot 1 each time and copy to SSD, it will cost around 170s.(Not including copy to final destination)
If I plot 1 each time and copy to 16TB HD, it will cost around 490s.(Including copy to final destination)
If I plot 2 each time and copy to 16TB HD, each one will cost around 550s. (Including copy to final destination)

I don’t think copy to SSD then copy to find destination is a good idea, because SSD will die and final bottleneck is copy speed. If copy speed(from memory to 3 or more HD) is faster than GPU plot speed, we don’t need SSD just need a large memory. I think 3 HD is enough(200MB/S for each one).

Suggestion are:

  1. GPU is very hot and I can not change GPU voltage, memery voltage,GPU frequency, memery frequency and fan speed like ETH miner.
  2. Bladebit always wait for copy done then goes to the next one even if I have enough memory space. I hope Bladebit can plot the next one without waitting for the copy done.
  3. is this compress plot a long term solution? I’m afraid I plot a lot and a few weeks later I have to switch to 101GB files again. I’m considering delete old 101gb files.

It will die after making a few PB of plots, it’s quite cheap (a few cents per plot) for what it is. Alternatively you can make a few raid0 with small harddrives.

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This is your advice:

below is my plan and suggestion:

Good luck with that !

your setup is not possible, you need a buffer of some kind.
3 or 4 cheap SATA ssd’s in raid 0 (or a enterprise NVME) will give you exactly that.
Please keep in mind that only the amount you need will be written (ie your total farm size if you replot everythinh)

The problem is, is that the RAM buffer needs to be free, before the next plot can start. Maybe it can work with 512GB ram as you have, But I am not sure if the plotter can keep the plot in memory while also starting a new plot. If it is possible then maybe your idea will work, I just don’t know.

In any case, there are a lot of second hand enterprise SSD’s for sale for quite low prices on sites like Ebay, and they can handle a lot of writes. That might be the easiest workaround.

But it also depends on how many plots you have in total?

I hope this will be a new feature in bladebit.

if the plotter can keep the plot in memory while also starting a new plot, then I need 220GB for plotting and 3* 79GB(Why 3? Because the plot speed is 79GB/180s = 433MB/s. So 3 disks(write speed more than 150MB/s) are enough) for caching plot files. Total memory usage is 457GB. So 512GB RAM is enough.

This is correct. If I just want to plot less than 10PB, then SSD as cache could be the best.

  1. I want to plot more
  2. RAM can re-sell if I stop plotting while SSD can not.

In that case you can try to setup 256G as a ramdrive and buffer plots on that.
The issue you will run into is that bladebit will try to create the 4th plot while you are transferring the other 3 plots…

I would go with that too! Good idea. Don’t know why I didn’t think of it.

After researching this I found that the issue is that bladebit uses Direct I/O en ram drives do not support this.

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I came to the same conclusion in my personal setup. Did you ever find a solution to this?

Not really no, I simply use an enterprise SSD as buffer, it can take 12PB of writes so I am not too worried as I only have 400TB to replot.

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