Multiple instances of MadMax plotter to plot in parallel?

Chia Plotting
22

what kind of ram/nvme do you have?

I also have 2x 2680v2 with 110GB Ramdisk and nvme(SN750) , my plots are just over 28 minutes.
DDR3 1600

currently I use -r 22 -K 2 for cpu settings, default buckets

23

ECC DDR3 1333. 8x 8GB and 4x 16GB - probably not ideal, just some old stuff I salvaged into 1.

Got some Silicon Power brand NVME for cheap.

24

I see, I was just curious where the difference was coming from, but I guess the ram speed explains it

25

The madMax plotter is even with less RAM then 110G (Linux OS) much faster then the chia plotter.

You can parallel plot. But for that, you need a 2 x 110G Ramdisk setup.

Wich OS are you using?

26

I managed to get more more, 256GB total. Hereā€™s my setup

Ubuntu 20.04
In my fstab as
tmpfs /path/to/TempRAM0 tmpfs rw,size=110G,mpol=bind:0 0 0
tmpfs /path/to/TempRAM1 tmpfs rw,size=110G,mpol=bind:1 0 0

Ran 2 instances of Madmax with:
numactl --cpunodebind=0 --membind=0 ā€“ chia-plotter -r16 -n $num -t $NVME0 -t2 /path/to/TempRAM0 -d /path/to/disk0 ā€¦blahā€¦blah
numactl --cpunodebind=1 --membind=1 ā€“ chia-plotter -r16 -n $num -t $NVME1 -t2 /path/to/TempRAM1 -d /path/to/disk1 ā€¦blahā€¦blah

Basically 2 ramdisk, 2 nvmes, 2 destination drives. Plot time is consistently 50m each. (24hours/50)*2 gives me 57 plots a day. So, 2x16TB (2x145plots) in about 5 days.

Running just 1 produces a plot every 36 mins. 24hours/36 = 40 per day.

Without numactl, plot time was inconsistent; between 40-80 mins. Would take too long to work out the statistics of that, so I didnā€™t bother.

Definitely not the fastest, but Iā€™m happy with my 7 year old bucket of rust.

27

Take a quick look at lstopo. Make sure the NVMe(s) youā€™re using for each plotter are hanging off the appropriate CPUā€™s PCIe lanes.

Also, when you mount your tmpfs, do you set the mpol option for each to the appropriate node? That could make a huge difference. tmpfs(5) - Linux manual page

29

Thanks for the tip. Never thought of the PCIe lanes. I have mpol for tmpfs. Anyway, Iā€™m done plotting. Will try it if and when I get more drives.

30

use your extra RAM to set up a cache in front of your plotter temp2 ssd drive to reduce wear. A 40GB+ RAM cache should cut down your SSD writes by ~50%+