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UPDATE - I just checked on the rigs and both miners were reporting they were hashing away just fine but the pool said bminer was offline. After restarting bminer the pool shows it back online again but there is a steep dip and rebound in the hashrate graph; earnings were affected as well, with dstm now at 0.0374 ZEN and bminer 0.0356 ZEN, so this wasn't a pool issue. I can't think of a worse failure mode for a miner, really - it was still drawing a huge amount of power and appearing to work, but not actually doing anything useful.
Could you share the failure log of Bminer? I would love to take a look.
It seems like a network issue that takes longer than usual to reconnect. Bminer does not shutdown GPU during reconnection, because it takes too long to re-init GPUs via Nvidia driver.
In future releases, I plan to add failover server support. I will also find a way to put GPU at idle states that draw less power during reconnection.
What failure log? As far as bminer was concerned it was working just fine. It was claiming to get shares accepted and scrolling back up the console window didn't reveal any issues with the network connection. Besides, I was still able to use the web on both mining rigs the entire time the miner was running so that rules out a connection issue. Very peculiar, really.