Issue with stale x11 blocks

Post by **Steve Sokolowski** » Mon Apr 17, 2017 8:47 pm

Some customers reported that they were having issues with x11 mining causing lost and orphaned blocks. After some investigation, Chris discovered that some x11 coins are not receiving updates when new blocks are found on the network, causing the data that is sent to miners to be stale.

We investigated this and it turns out that one of the servers hosting x11 data isn't able to connect to the mining server, perhaps due to a NAT misconfiguration or something like that. The reason this issue only affects x11 coins is because Chris bought a new server for x11 mining and installed all the coins on it, but didn't install any new scrypt coins there. The coin daemons "connect" to the mining server and the data goes into a black hole. Thus, miners are never told that new blocks are available. We tried to fix this for a few hours and determined that it's going to take long enough that we'll have to come back to it in the morning.

In the meantime, it appears that some proportion of x11 money was never earned. Some customers who solo mined the coins that were on that server were disproportionately affected, because they didn't switch to other, working, coins. There were no scrypt coins on that server and therefore no scrypt mining was affected.

Chris will use profits from the scrypt side of the business to pay x11 miners whose balances are too low; he'll calculate that tomorrow. The x11 pool would be uncompetitive if we left it online without so many coins, so we turned it off for now. As soon as he fixes the problem, we'll re-enable x11 mining. Sorry for the trouble, and thanks for your understanding!