Software components
Understanding the components of Lotus is necessary in understanding subsequent sections on sealing, and what it means to build well-balanced storage provider architecture.
The diagram below shows the major components of Lotus:
The following components are the most important to understand:
Lotus daemon
Lotus miner
Lotus worker
Boost
Click here for a compatibility matrix of the different components and the required Golang version.
Lotus daemon
The daemon is a key Lotus component that does the following:
Syncs the chain
Holds the wallets of the storage provider
The machine running the Lotus daemon must be connected to the public internet for the storage provider to function. See the Lotus documentation for more in-depth information on connectivity requirements.
Syncing the chain
Syncing the chain is a key role of the daemon. It communicates with the other nodes on the network by sending messages, which are, in turn, collected into blocks. These blocks are then collected into tipsets. Your Lotus daemon receives the messages on-chain, enabling you to maintain consensus about the state of the Filecoin network with all the other participants.
Due to the growth in the size of the chain since its genesis, it is not advised for storage providers to sync the entire history of the network. Instead, providers should use the available lightweight snapshots to import the most recent messages. One exception in which a provider would need to sync the entire chain would be to run a blockchain explorer.
Synced chain data should be stored on an SSD; however, faster NVMe drives are strongly recommended. A slow chain sync can lead to delays in critical messages being sent on-chain from your Lotus miner, resulting in the faulting of sectors and the slashing of collateral.
Another important consideration is the size of the file system and available free space. Because the Filecoin chain grows as much as 50GB a day, any available space will eventually fill up. It is up to storage providers to manage the size of the chain on disk and prune it as needed. Solutions like SplitStore (enabled by default) and compacting reduce the storage space used by the chain. Compacting involves replacing the built-up chain data with a recent lightweight snapshot.
Holding wallets
Another key role of the Lotus daemon is to host the Filecoin wallets that are required to run a storage provider (SP). As an SP, you will need a minimum of 2 wallets: an owner wallet and a worker wallet. A third wallet called the control wallet) is required to scale your operations in a production environment.
To keep wallets safe, providers should consider physical access, network access, software security, and secure backups. As with any cryptocurrency wallet, access to the private key means access to your funds. Lotus supports Ledger hardware wallets, the use of which is recommended, or remote wallets with lotus-wallet on a remote machine (see remote lotus wallet for instructions). The worker and control wallets can not be kept on a hardware device because Lotus requires frequent access to those types of wallets. For instance, Lotus may require access to a worker or control wallet to send WindowPoSt proofs on-chain.
Control wallets
Control wallets are required to scale your operations in a production environment. In production, only using the general worker wallet increases the risk of message congestion, which can result in delayed message delivery on-chain and potential sector faulting, slashing, or lost block rewards. It is recommended that providers create wallets for each subprocess. There are five different types of control wallets a storage provider can create:
PoSt wallet
PreCommit wallet
Commit wallet
Publish storage deals wallet
Terminate wallet
The lotus-miner also gets an address to which funds can/should be sent. This address can be used to pay any fees and collateral. Withdrawal from this address is only possible with the owner wallet private key.
Lotus miner
The Lotus miner, often referred to using the daemon naming syntax lotus-miner, is the process that coordinates most of the storage provider activities. It has 3 main responsibilities:
Storing sectors and data
Scheduling jobs
Proving the stored data
Storing sectors and data
Storage Providers on the Filecoin network store sectors. There are two types of sectors that a provider may store:
Sealed sectors: these sectors may or may not actually contain data, but they provide capacity to the network, for which the provider is rewarded.
Unsealed sectors: used when storing data deals, as retrievals happen from unsealed sectors.
Originally, lotus-miner was the component with storage access. This resulted in lotus-miner hardware using internal disks, directly attached storage shelves like JBODs, Network-Attached-Storage (NAS), or a storage cluster. However, this design introduced a bottleneck on the Lotus miner.
More recently, Lotus has added a more scalable storage access solution in which workers can also be assigned storage access. This removes the bottleneck from the Lotus miner. Low-latency storage access is critical because of the impact on storage-proving processes.
Keeping a backup of your sealed sectors, the cache directory, and any unsealed sectors is crucial. Additionally, you should keep a backup of the sectorstore.json file that lives under your storage path. The sectorestore.json file is required to restore your system in the event of a failure. You can read more about the sectorstore.json file in the lotus docs.
It is also imperative to have at least a daily backup of your lotus-miner state. Backups can be made with:
The sectorstore.json file, which lives under your storage path, is also required for restoration in the event of a failure. You can read more about the file in the Lotus docs.
Scheduling jobs
Another key responsibility of the Lotus Miner is the scheduling of jobs for the sealing pipeline and storage proving.
Storage proving
One of the most important roles of lotus-miner is the Storage proving. Both WindowPoSt and WinningPoSt processes are usually handled by the lotus-miner process. For scalability and reliability purposes it is now also possible to run these proving processes on dedicated servers (proving workers) instead of using the Lotus miner.
The proving processes require low-latency access to sealed sectors. The proving challenge requires a GPU to run on. The resulting zkProof will be sent to the chain in a message. Messages must arrive within 30 minutes for WindowPoSt, and 30 seconds for WinningPoSt. It is extremely important that providers properly size and configure the proving workers, whether they are using just the Lotus miner or separate workers. Additionally, dedicated wallets, described in Control wallets, should be set up for these processes.
Always check if there are upcoming proving deadlines before halting any services for maintenance. For detailed instructions, refer to the Lotus maintenance guide.
Lotus worker
The Lotus worker is another important component of the Lotus architecture. There can be - and most likely will be - multiple workers in a single storage provider setup. Assigning specific roles to each worker enables higher throughput, sealing rate, and improved redundancy.
As mentioned above, proving tasks can be assigned to dedicated workers, and workers can also get storage access. The remaining worker tasks encompass running a sealing pipeline, which is discussed in the next section.
Boost
Boost is the market component for storage providers to interact with clients. Boost is made of several components (such as boostd, boostd-data, yugabytedb, booster-http etc.). It works as a deal-taking engine (from deals made by clients or other tools), and serves data retrievals to clients who request a copy of the data over graphsync, bitswap or http.
Boost has become a critical component in the software stack of a storage provider and it is therefore necessary to read the Boost documentation carefully.
Boost requires YugabyteDB as of version 2.0. Plan your deployment so that you understand the concepts of Yugabyte well enough. See the Boost documentation for more details.
Helpful commands
The following commands can help storage providers with their setup.
Backup Lotus miner state
It is imperative to have at least one daily backup of your Lotus miner state. Backups can be made using the following command:
View wallets and funds
You can use the following command to view wallets and their funds:
Check storage configuration
Run the following command to check the storage configuration for your Lotus miner instance:
This command return information on your sealed space and your scratch space, otherwise known as a cache. These spaces are only available if you have properly configured your Lotus miner by following the steps described in the Lotus documentation.
In some cases it might be useful to check if the system has access to the storage paths to a certain sector. To check the storage paths to sector 1 for instance, use:
View scheduled jobs
To view the scheduled sealing jobs, run the following:
View available workers
To see the workers on which the miner can schedule jobs, run:
View proving deadlines
To check if there are upcoming proving deadlines, run the following:
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