Coin Metrics performed a study which attempted to launch full nodes and then re-create the full blockchain history for 8 major cryptocurrencies, in order to conduct an audit and verify the supply of these cryptocurrencies. Auditing is critical for cryptocurrencies since both Stellar (XLM) and Bitcoin Private (BTCP) have deviated significantly from their expected supply in the past. Essentially, it is important to verify rather than trust, in order to ensure that no fraud or code bugs are occurring.
However, Coin Metrics ran into difficulties when trying to set up full nodes for EOS, Ripple (XRP), and Stellar (XLM). Essentially, the blockchain sizes for these cryptocurrencies are so big that running a full node is impossible for most users, leading to potentially dangerous levels of network centralization, as will be explored in this article.
Coin Metrics Could Not Even Run A Ripple (XRP) Full Node Due To Ridiculous Storage Requirements
Ripple (XRP) apparently requires tens of terabytes (TB) of storage space in order to download its database, making it impractical to run and synchronize according to Coin Metrics. Notably, Coin Metrics runs 35 different types of cryptocurrency full nodes, and it really says something if they think that running a Ripple (XRP) full node is unfathomable.
If Coin Metrics cannot run a Ripple (XRP) full node, then almost all individuals and most businesses could not run a full node either. Perhaps banks who are using Ripple (XRP) could afford to put together a full node, which would require thousands of dollars of storage devices and extremely fast internet access.
That being said, a Ripple (XRP) validator node can successfully participate in the consensus process with just the 256 most recent ledger versions, which requires well less than 1 GB of disk space. However, such nodes do not have the ability to look at any of the past transactions.
There are apparently only 140 Ripple (XRP) validator nodes at this time on the mainnet, and it is unknown how many of these are full nodes, but likely only a small fraction. Indeed, only 6 Ripple (XRP) nodes have been online for more than 100 days, with only 17 nodes online for a month, and perhaps these are the dedicated full nodes, although this cannot be confirmed.
Therefore, the Ripple (XRP) network lacks the primary benefits of decentralization since it likely has a tiny amount of actual full nodes. If these full nodes were compromised, and there were no backups for the tens of TB of blockchain history, then pretty much the entire history of Ripple (XRP) would be lost. Also, Ripple (XRP) has so few nodes in general that it may be susceptible to a DDoS attack.
Even worse, a bad actor could launch enough nodes to take over a majority of the network, which would result in Ripple (XRP) automatically declaring itself to be broken and then going offline.
Stellar (XLM) Is So Centralized That A Few Full Nodes Going Offline Took The Network Down
Ripple (XRP) is not alone in being having centralization problems due to the blockchain being oversized. Stellar (XLM) is quite similar to Ripple (XRP) and has a blockchain size in the multiple TB range. There are only 34 Stellar (XLM) full nodes running at the time of this writing, resulting in centralization issues.
Indeed, a study performed in January and May found that if two or three of the full nodes managed by the Stellar Development Foundation go down, then the entire network can end up going down due to a chain reaction. Lo and behold, in May this exact scenario happened and the Stellar (XLM) network went offline for an hour. This incident is an example of how centralization of full nodes can compromise a network in unexpected ways.
EOS Only Has A Handful Of Full Nodes
Coin Metrics found that EOS was having severe scalability issues as well, and it took over a month to download the multiple TBs of EOS blockchain data, despite using the fastest storage available. This indicates that someone with a regular internet connection and regular storage hardware probably could not download an EOS full node. Also, the EOS full node apparently corrupted its own database if it wasn’t shut down carefully.
A report from March indicated that there were only 5 EOS full nodes in existence, and 20% of EOS transactions require the full blockchain history data in order to work. If these full nodes suddenly became inaccessible then dApps would not function properly, showing how dangerously centralized EOS is.
Running A Bitcoin (BTC) Full Node Can Be Difficult Too, But The Network Is Sufficiently Decentralized
Although Ripple (XRP), Stellar (XLM), and EOS are among the most impractical cryptocurrencies for running a full node, running a Bitcoin (BTC) full node can be difficult as well. Currently, the Bitcoin (BTC) blockchain is just over 250 GB, which is small in terms of storage but can take months to download at typical internet speeds. Further, Bitcoin (BTC) full nodes require unmetered internet connections with high upload limits, and often internet connections are metered and throttled nowadays beyond a certain bandwidth threshold.
Beyond the problem of being able to download the Bitcoin (BTC) blockchain in a reasonable amount of time, often internet service providers and computer firewalls block a Bitcoin (BTC) full node from communicating with the network, and it can be a long and arduous process to open all of the correct ports and take down every firewall.
The result is that the number of Bitcoin (BTC) full nodes has been consistently declining long term, from around 12,500 in early 2018 to 9,500 currently. That being said, unlike EOS, Ripple (XRP), and Stellar (XLM), Bitcoin (BTC) does not just depend on nodes for security, but also has a powerful mining network.
The thousands of nodes that Bitcoin (BTC) does have are likely a sufficient amount for decentralization purposes. However, it is notable that even with Bitcoin (BTC) a regular user would probably have a hard time getting a full node running, and Bitcoin’s (BTC) node distribution is becoming slightly more centralized long term.
EOS, Ripple (XRP), And Stellar (XLM) Sacrificed Decentralization For Transaction Scalability
Thus, it is practically impossible to run full nodes for the major cryptocurrencies EOS, Ripple (XRP), and Stellar (XLM), resulting in only a tiny amount of full nodes for each network. This makes these cryptocurrencies dangerously centralized. In the case of Stellar (XLM), even a few of the main nodes going down can stop the entire network. Likewise, Ripple (XRP) could easily be forced offline if an attacker was running a majority of nodes. EOS would not function properly if something happened to the handful of full nodes that do exist.
Ultimately, the point of decentralization is that governments and other entities cannot take down a properly decentralized network, and a properly decentralized network is immutable and cannot be modified by any centralized entity. EOS, Stellar (XLM), and Ripple (XRP) have chosen to sacrifice decentralization for transaction scalability, but it seems like a nonsensical trade-off since without proper decentralization most of the benefits of cryptocurrency are lost.