dagmining
When mining it's very common for a DAG to become corrupted. To resolve the problem deleting the file and restarting the miner is required.
I'm working on a miner manager to control RIGs and one of the features I want to include is to check if a DAG was corrupted instead of deleting it every X hours.
At this moment I'm only reading "REJECTED" on proxy which can be a cause of corrupted DAG.
So, there is any way (code/commandline) to check if the current DAG file is corrupted?
Okay found the answer on another forum. It just means the next phase of the DAG is happening soon, apparently this takes place every 30,000 blocks. It becomes bigger.
At the time of writing this question the block didn't exist yet as it was still in the 1070000's - just one minute ago it happened.
DAG stands for Directed Acyclic Graph. In Ethereum, a DAG is created every epoch using a version of the Dagger-Hashimoto Algorithm combining Vitalik Buterin's Dagger algorithm and Thaddeus Dryja's Hashimoto algorithm.
There are quite a few places where the DAG is defined in the docs and literature. These are collated below:
From the yellow paper:
...d being the current DAG, a large data set needed to compute the mix-hash...
From Wikipedia:
Directed Acyclic Graph: image credit David Eppstein
In mathematics and computer science, a directed acyclic graph (DAG), is a finite directed graph with no directed cycles. That is, it consists of finitely many vertices and edges, with each edge directed from one vertex to another, such that there is no way to start at any vertex v and follow a consistently-directed sequence of edges that eventually loops back to v again. Equivalently, a DAG is a directed graph that has a topological ordering, a sequence of the vertices such that every edge is directed from earlier to later in the sequence.
From https://github.com/ethereum/wiki/wiki/Ethash-DAG:
...a great huge dataset known as the DAG...
The Ethash algorithm expects the DAG as a two-dimensional array of uint32s (4-byte unsigned ints), with dimension (n × 16) where n is a large number. (n starts at 16777186 and grows from there.) Following the magic number, the rows of the DAG should be written sequentially into the file, with no delimiter between rows and each unint32 encoded in little-endian format.
From Vitalik Buterin's (I think) Dagger Paper, Dec 2013:
Dagger, a memory-hard proof of work based on moderately connected directed acyclic graphs (DAGs, hence the name), which, while far from optimal, has much stronger memory-hardness properties than anything else in use today.
Essentially, the Dagger algorithm works by creating a directed acyclic graph (the technical term for a tree where each node is allowed to have multiple parents) with ten levels including the root and a total of 2^25 - 1 values.
From https://github.com/ethereum/wiki/wiki/Mining#so-what-is-mining-anyway:
...calculating the PoW (Proof of Work) requires subsets of a fixed resource dependent on the nonce and block header. This resource (a few gigabyte size data) is called a DAG. The DAG is totally different every 30000 blocks (a 100 hour window, called an epoch) and takes a while to generate.
From https://github.com/ethereum/wiki/wiki/Mining#ethash-dag
a DAG (directed acyclic graph) for the proof of work algorithm
From https://github.com/ethereum/wiki/wiki/Mining#the-algorithm
a large, transient, randomly generated dataset
From https://github.com/ethereum/wiki/wiki/Ethash
The DAG is the "dataset" in this description of the Ethash algorithm, emphasis mine:
- There exists a seed which can be computed for each block by scanning through the block headers up until that point.
- From the seed, one can compute a 16 MB pseudorandom cache. Light clients store the cache.
- From the cache, we can generate a 1 GB dataset, with the property that each item in the dataset depends on only a small number of items from the cache. Full clients and miners store the dataset. The dataset grows linearly with time.
- Mining involves grabbing random slices of the dataset and hashing them together. Verification can be done with low memory by using the cache to regenerate the specific pieces of the dataset that you need, so you only need to store the cache.
Best Answer
The solution I found was to parse my wallet's page on dwarfpool looking for the string "DAG corrupted" in its content with a little Node.JS script. It should work with any pool.
Obviously if you do not write code it's not that easy. GoldMiner does check DAG corruption and automatically restarts mining, it has a cool interface, great for non-coders imho.