Network cryptocurrencies DASH shortly after the release of the next version of the Dash Core v0.12.2.2 there was a very unpleasant situation — the miners began to report multiple increase in the number of «abandoned» blocks (orfanov).
As a result of orfanov miners lose wasted all the work spent on the production of the next unit. During normal operation of the network the proportion of «abandoned» blocks are typically a fraction of a percent, in particular, in Dash they are usually appears less than 5 pieces a day. However, from 27 to 29 December this number has increased many times — so, December 29 appeared 54 orfan.
The problem is exacerbated by the fact that in recent years, the Chinese mining pool Antpool has significantly increased its capacity, and was even able to get more than 50% of the network hash rate yet that rarely happens in major currencies (at the time of publication pool maintains a share of about 50%). Therefore, in the community, there were suggestions that the pool trying to get control over the network.
It looks as follows: for example, P2pool finds a block and sends it over the network. After a few seconds it finds the block AntPool, but does not include a unit of a competitor in its chain. Because of the superiority in hazrate he quickly finds the next block, thus obtaining a longer chain. In the end, the winner is a block Antpool, despite the fact that P2pool found a block earlier. This method is called «selfish mining» and can be widely applied in those cases, if one of the miners (pools) significantly outperforms the others in Hasrat.
Hash rate DASH only for the past two months, rose more than 12 times. And most of this growth occurred in the Antpool, as its owner, the company Bitmain, can connect equipment directly from the factory — much cheaper and without the cost of logistics and intermediaries.
One of the first to sound the alarm the owner of the Russian node of P2Pool — during the day the pool was able to produce 5 units, and they were all «ohanami». A host of other pool — Zpool — said that just removes the DASH until the issue is resolved.
The situation with ohanami immediately after its discovery was announced by the developers of the coin, however, two days they distanced themselves from what is happening, and only when the problem became obvious to all, the investigation began.
The situation was resolved fairly quickly. It turned out that for some reason has broken the compatibility of the wallets of miners with different versions. Therefore, when, after a new release on 19 December, the miners began to be updated, there was a conflict with Antpool and several other pools, wallets which have not been updated.
After Antpool and other pools at the request of the developers have updated the wallets and restarted the server, problem with the distribution blocks disappeared. Currently, developers are engaged in the search for the causes of the accident.