Plot format

Apr 6, 2024

Updated: Jan 30, 2025

voidxno

Plot format, MMX.

IMPORTANT: My own understanding, reading comments when mainnet plot format was rolled out with testnet11. Still relevant info, as an introduction. Reference official information if unsure.

TLDR;

• Plot format for MMX (mainnet), introduced with testnet11
• Resistant against compression
• Two types, HDD and SSD-plots (min k29, max k32):

  	k29	k30	k31	k32
  hdd	36.2 GiB	75.3 GiB	155.4 GiB	320.3 GiB
  sdd	14.7 GiB	30.3 GiB	62.3 GiB	128.3 GiB

• SSD-plots have missing data, smaller, but require high disk IOPS
• Plotting: GPU required, full RAM, partial RAM, disk mode
• Plotting: Any old 4GB VRAM (Pascal), k32 needs 6GB VRAM
• Farming: CPU only (plots), GPU not supported (not worth it)
• Farming: Still iGPU/GPU recommended for VDF-verify (CPU possible)
• Compression: Still supported, practically not worth it (1-4%, C1-C15)
• Bonus: Open source mmx-node builds (GPU plotter too)

Compression

Previously

Plot compression is not really traditional compression. It is information left out of plot file, reducing its size. Reconstructed on-the-fly when farming.

Data in plot files are several nested tables that takes a certain amount of time to create (plotting). If passing plot filter, this data is used to create potential proofs. That again could be the winning proof for a block.

Previously plot files where cleverly reworked to smaller sizes, with missing information. When farming, that information was reconstructed on-the-fly when needed. Branded as plot compression.

Today

Testnet11 introduced a new plot format that are orders of magnitude more resistant to these kind of compression techniques. Reworked by Max to make it practically worthless. Not possible to be 100% compression resistant. It’s math. But reworked algorithms, required proof time, limits it greatly.

As a principle, compression is still an option. The higher compression chosen (C1-C15), longer plot times, more CPU compute when farming. Gaining only 1-4% compression, compared to +200% with other Proof of Space.

HDD-plots have C0-C4 as recommended compression (1%). Still easily processed by CPU when farming. Going further up, too much load/time on CPU.

SSD-plots

SSD-plots are a type of pre-compressed plots, missing hashes. Reconstructed on-the-fly when farming, but requires very high disk IOPS. Storing them on HDD will not work, not enough IOPS on spinning platters. Goal is to balance cost/reward potential between SSD and HDD storage (2.5x SSD advantage, but more expensive media).

Basically: Given identical k-size, SSD-plots has same effective space on network as HDD-plots. Takes less space to store (2.5x advantage), but more expensive media (SSD).

Given the high IOPS for SSD-plots, recommended to use C0 for compression (0%).

Plotting

RAM requirements for plotter, in memory GB (similar for HDD and SSD-plots):

	full RAM	partial RAM	disk mode
hdd/sdd-k29	60 GB	32 GB	8 GB
hdd/sdd-k30	110 GB	64 GB	8 GB
hdd/sdd-k31	216 GB	120 GB	8 GB
hdd/sdd-k32	410 GB	232 GB	8 GB

NOTE: Disk mode usually less than 8 GB, depends on -S streams option.
NOTE: If close to 32 GB, 32 GB system RAM not enough. 48/64 GB needed.

Temp disk space needed when plotting (similar for HDD and SSD-plots):

	full RAM	partial RAM	disk mode
hdd/sdd-k29	0.0 GiB	24 GiB	51 GiB
hdd/sdd-k30	0.0 GiB	48 GiB	101 GiB
hdd/sdd-k31	0.0 GiB	100 GiB	202 GiB
hdd/sdd-k32	0.0 GiB	200 GiB	404 GiB

Total disk writes when plotting, in TiB written:

	full RAM	partial RAM	disk mode
hdd/sdd-k29	0.04 / 0.02 TiBW	0.08 / 0.06 TiBW	0.33 / 0.28 TiBW
hdd/sdd-k30	0.08 / 0.03 TiBW	0.16 / 0.12 TiBW	0.68 / 0.57 TiBW
hdd/sdd-k31	0.16 / 0.06 TiBW	0.33 / 0.25 TiBW	1.40 / 1.14 TiBW
hdd/sdd-k32	0.32 / 0.13 TiBW	0.67 / 0.50 TiBW	2.88 / 2.27 TiBW

• Testnet11 introduced a new farmer key, 33 bytes ECDSA vs old 48 BLS (-f, 66 chars vs old 96).

Follow #mmx-general on Discord.

Farming

Disk seeks per plot (independent of k-size or C-compression):

	pass filter	full proof
hdd	~2	~256
ssd	~4096	0

Follow #mmx-farming on Discord.