Mining Hardware Guide
A guide to building your first Arweave miner.
There are 2 phases to Arweave mining:
Syncing and Packing
Mining
This guide will focus on the mining phase.
The Arweave dataset (called the "weave") is broken up into 3.6TB partitions (3,600,000,000,000 bytes). There are 50 partitions as of March, 2024, although that will grow over time as users upload more data. The Arweave protocol provides a strong incentive to mine against the complete dataset or multiple copies of the complete dataset (called "full replicas").
A full replica miner can opt for a single node that reads from all 50 partitions, or they can operate several nodes that each read from a subset of the data and coordinate with each other to assemble a full replica. This is called "coordinated mining". In all cases the primary bottleneck is typically disk read bandwidth: you will need to maintain an average read throughput of at least 200 MB/s for each 3.6TB partition.
Below we'll outline the main considerations when building your miner, and provide an example configuration.
Mining configurations vary tremendously from miner to miner, and we're not yet able to certify specific component compatibility. As you build your miner you will need to verify compatibility between components.
Mining Platform
There are 2 possible mining configurations:
A single node mining a full replica
Multiple nodes each mining a partial replica and coordinating together to assemble a full replica
To date the dominant strategy has been to adopt a multi-node / coordinated mining approach. As the weave continues to grow we believe this strategy will only increase in popularity.
An example 16-partition node could include:
1x mid-tier Ryzen CPU (e.g. Ryzen 5/7/9)
1x motherboard with at least one PCIe 3.0 8x slot
1x 16-port Host Bus Adapter (HBA)
SAS2 or SAS3, LSI or Broadcom HBA, 16i or 16e
For example:
LSI SAS 9201-16i (SAS2)
Broadcom 9305-16e (SAS3)
4x Mini SAS to SATA breakout cables
Mini SAS ports can be either SFF-8087 or SFF-8643
16x 4TB 7200rpm SATA HDDs
1x PSU with at least 16 SATA ports
You would then coordinate 3 or more of these nodes to cover the full weave.
It is also possible to configure a single node that mines against more than 16 partitions. We outline the main considerations below to provide guidance should you wish to move away from the example configuration above.
Note: it is also possible to mine efficiently as a partial replica miner. In that case you will want to join a Mining Pool that is able to coordinate your partitions with other miners in the pool so that you are still able to get the full replica hashrate bonus.
Storage Bandwidth
The primary bottleneck of a miner is storage read bandwidth. Specifically you need to maintain at least an average 200MB/s read throughput per 3.6TB partition. Read throughput is measured from the disk to the CPU. The main components involved are:
Hard Disk Drive (HDD)
Host Bus Adapter (HBA) (optionally with SAS expander)
PCIe slots on the motherboard
We'll now cover each component in a bit more depth.
Hard Disk Drive (HDD)
The main requirement is that your HDDs are able to provide an average read throughput of 200MB/s per 3.6TB partition. Since modern 7200rpm HDDs are typically rated for 200MB/s, the simplest and recommended approach is to buy one 4TB HDD for every partition you plan to mine. The extra 0.4TB is used for metadata stored adjacent to the weave data.
However, each miner's situation is different and miners may find it more profitable to mine different configurations, for example:
Distribute 3 partitions across 4x 3TB HDDs
Use 8TB HDDs, assign 1 partition to each HDD, and use the extra space for infrequently accessed storage.
Similarly, both SATA and SAS HDDs will work fine, you will just need to ensure compatibility between the HDDs, cabling, and other components.
Host Bus Adapter (HBA)
Most motherboards don't integrate enough SATA connectors to support 16+ disks, so you will likely need at least one HBA. There are many, many different HBAs to choose from. The first question is: how many disks will you connect to the HBA? Once you have that number you can work through the following attributes to select your HBA:
SAS version
Number of SAS lanes
Optional SAS expander
Number of PCIe lanes and PCIe version
Internal or external SAS ports
Miscellaneous
Let's work through them assuming our sample configuration of 16 SATA disks per node.
16 SATA disks will require a total of 16 x 1.2Gbps = 25.6 Gbps of sustained, average read throughput.
Note: we don't recommend using RAID. In general neither software nor hardware RAID provide enough benefits to offset the cost and complexity - and under some configurations can hurt performance. As always: each miner's situation is different. Some miners with expertise or access to hardware may find RAID configurations that are beneficial.
SAS Version
SAS (stands for Serial-Attached SCSI) is a data transfer protocol. There are 3 different speed standards for SAS
SAS-1: 3 Gbps per lane
SAS-2: 6 Gbps per lane
SAS-3: 12 Gbps per lane
All the standards are interoperable, however when combining cables and peripherals at different SAS standards, the data transfer throughput is determined by the slowest component. e.g. if you attach a SAS-1 expander to a SAS-3 HBA, your throughput will be 3 Gbps per lane, not 12 Gbps per lane.
Because of this we recommend deciding on a standard early and selecting all components at that standard or higher.
We recommend sticking with SAS-2 or SAS-3 as it will help ensure the SAS speed does not become a bottleneck if you decide to add more disks in the future.
Number of SAS Lanes
HBA product names end in a number and a letter, like 8i, 16i, 16e. The number refers to the number of SAS lanes supported by the HBA. There are 4 lanes per HBA connector (typically a Mini-SAS connector, but there are other ports too). So a "SAS-2 LSI HBA 16i" has 4 connectors, each with 4 SAS lanes, for a total of 16 lanes. 16 lanes x 6 Gbps = 96 Gbps of aggregate throughput.
Without using a SAS expander (discussed below) each HBA lane can connect directly to a single HDD. So if you want to support 16 disks, you need a 16-lane (sometimes called 16-port) HBA. Each disk requires 1.2 Gbps of read bandwidth, which is well below the SAS bandwidth (all versions).
We recommend using a 16i or 16e HBA to connect 16 disks.
As you may have noticed each HBA lane has enough bandwidth to theoretically support multiple disks. A 6Gbps SAS-2 lane, for example, could theoretically support 5 disks at 1.2 Gbps per disk. To achieve this, you would need to add a SAS Expander.
SAS Expander
Using a SAS Expander you can connect multiple disks to each SAS lane on your HBA. Aligning SAS versions is particularly important when using a SAS Expander. For example if you use a SAS-1 Expander with a SAS-2 HBA and try to attach 4 disks to each SAS lane, the lower SAS-1 throughput of 3 Gbps will throttle your read rate.
Using a SAS Expander also requires an extra PCIe slot (discussed below), and is one more component to troubleshoot and replace. For these reasons we don't recommend using a SAS expander unless you are prepared for the additional complexity.
Number of PCIe lanes and PCIe version
The final connection is from the HBA to the motherboard via the PCIe slot.
To ensure the PCIe bandwidth itself does not become a bottleneck we recommend sticking with adapters that use PCIe version 3.0 with 8 PCIe lanes adapters. PCIe 3.0 8x provides 62.4 Gbps of bandwidth which is enough to handle up to 39 disks.
Internal vs. External
One more note on the HBA: the letter at the end of the product number (i.e. 16i vs. 16e) refers to "internal" vs. "external" connectors. A 16i HBA will expose the Mini-SAS connectors to the interior of the case, a 16e will expose the MIni-SAS connectors to the exterior of the case. We have no recommendation here as it depends on where you plan to mount your disks.
Miscellaneous
Since computer systems are complex and the components incredibly varied, it's possible that there may be other bandwidth limitations in your system separate from the HBA and disks. You may want to review the specifications of any other components in your system to ensure they don't restrict your available read bandwidth.
PCIe Slots on the Motherboard
As mentioned above in the HBA section, we recommend using 8-lane PCIe 3.0 or better for connecting your HBA and any SAS expanders. You'll want to keep this in mind when buying a motherboard to ensure it has enough slots of the right type to accommodate your HBA(s) and any SAS expanders.
Note: Syncing and Packing Phase
The preceding hardware configurations focus on the mining phase. Before you can start mining you need to download a full replica (177 TB as of March, 2024) and then pack it to your mining address. Packing is a CPU-intensive encryption process (the weave data is symmetrically encrypted using your mining address). Generally miners will sync and pack in parallel - packing data as they download it.
This phase is heavily bottlenecked by available download bandwidth and CPU capacity. For example if your download bandwidth is 1 Gbps it will take over 16 days to download the full data set. The faster your download speed, the faster you can sync the dataset. However once you start mining, a 100-200 Mbps connection will be more than enough.
After you have downloaded some data you have to pack it. A 16-core Ryzen 9 7950x can pack about 90 MB per second - which means it would take about 22 days to pack the full data set using a single 16-core Ryzen 9 7950x. Since these two phases (syncing and packing) can happen in parallel, this example miner with 1Gbps download bandwidth and a 16-core Ryzen 9 7950x could sync and pack the full data set in 22 days.
The saving grace to all this is that you only need to download and pack the data once per replica. Some miners will rent CPU time and access to bandwidth to reduce the time of this phase.
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