Rejected Shares in Mining

 

Stale/Rejected Shares in Mining

Rejected Shares in Mining

 

Rejected shares are essentially rejected work units that your miner creates because it has been disconnected from the blockchain network. The rejection rate of shares can be an essential indicator of how successful your mining operation is.

Shares that get generated but could not be submitted to the mining pool due to network fluctuations or other factors are known as rejected shares. Rejected shares occur when miner hardware is sending too quickly, meaning that the data is not correctly transmitted, and thus, it is returned back as rejected by the mining pool. This issue can be caused by a disconnection from the pool, hardware instability, and bad internet connection, among many other reasons.

 

Stale Shares in Mining

If you submit a home late to a teacher, tho’ you have done the work, you will receive a ‘zero’ or a ‘negative’ marking. This is analogous to stale/rejected shares in mining. In other words, a stale share is when your miner submits a share to the pool when the pool has already moved onto mining the next block.

 

Causes of Stale Shares

The main cause of stale shares is latency in the network. This is the time it takes for the data to be transferred from the miner to the pool. This is usually measured in milliseconds and defined as ping. When the pool finds a new block it needs to send new shares out to all the miners on the pool. So there will always be latency between the pool finding new shares/blocks, sending it out to the miners, and the miners solving the shares and sending them back.

Long polling allows the pool to notify all of its miners when there is a change in blocks. This allows miners to request new shares immediately. Check to make sure your mining pool and software supports long polling, otherwise your miner will be forced to finish the old shares on the solved block before you receive new shares. When the long polling notification gets sent all the miners that support it request new shares at the same time. This causes an influx of network activity and could slow down the pool. If the pool is too slow to issue you new shares, there will be a larger amount of stale shares.

 

Reduce Stale Shares

The best way to reduce stale shares is to improve the network connection from your miner to the pool. Make sure you have a reliable internet connection on your miner, it doesn't need to be fast. Most miners will use ethernet over wifi for the increase in stability. Make sure you are also mining to a pool that is geographically close to your miners. Having a higher hash rate can also reduce stale shares. The faster your miner solves shares, the faster it will check for new shares. This means that the window between solving a share, submitting it, and getting a new one will be reduced.

 

Calculating the Rejection Rate

The rejection rate can be calculated as follows:

 

Total number of rejected shares/Total number of submitted shares

 OR

Rejection rate = (expired number + repetition number + other) / (received number + expired number + repetition number + other)

This provides an estimated figure for how many work units were rejected out of all those attempted by the miner. Also, it is important to note that different pools have different thresholds for rejecting work units so this figure may vary between pools depending on their specific requirements.

 

Reducing and Avoiding High Rejection Rates

With the increasing competition in the cryptocurrency space, it is becoming more crucial for miners to ensure that they are as efficient as possible. The rejection rate measures the ratio of rejected shares from a miner relative to the total amount of shares submitted. A lower number (of rejection rate) means the miner’s effort is being rewarded with actual bitcoin rewards. This makes them more competitive and will enable them to make bigger profits in the long run.

 

Rejection rate is below 1%

A rejection rate below 1% is entirely normal, but it can be improved as well. You will need to know how many shares were received and the number of expired/repeated shares. Then, just divide that total by the number of received shares to get your rejection rate. With the accurate records, you can continually work towards improving this important metric and ensure your business remains successful.

 

What, if the rejection rate is higher than 1%.

If the rejection rate is higher than 1%, it’s essential to take the right steps to diagnose and solve the issue, as this may impede profitability as miners miss out on rewards from failed attempts at solving blocks on the blockchain network. Steps such as the following could hopefully rectify the problem:

a.     Shutting down and restarting your miner.

If you have many miners on your mining farm, you can use the bulk tool APMinerTool to manage your miners.

b.    Checking your network connection

If the rejection rate of a particular miner is abnormal, it is recommended to replace the network cable and network cable connector to the miner.

c.     Replacing your router or switch entirely.

If the rejection rate of all miners connected to the same router or switch is abnormal, it is recommended to check the entire network and replace the router or switch for testing.

Such steps would ensure that you do not miss out on any potential reward by leaving the issue unresolved.