If you can dump AC vent outdoors, then you can dump Miner air outdoors and that's all that OP needs.

That said, if power cost is zero, then cool it all you want.

Airflow to the environment is your only answer.

I rented a warehouse space with 100KW 3-phase electrical service.  In Texas.  Airflow in and out is all you need.  Filter the air and keep dust out of your units.  Still need to clean them occasionally.

Bitcoin mining is the process of turning electricity into money.  AC cooling will triple or quadruple your power bill, likely sending your costs beyond your profits.

Standalone portable AC units need to exhaust their heat somewhere, if you are exhausting this outdoors, then you can exhaust the miners outdoors.

Experiences

 - Miners slow down a bit when ambient air is 100F
 - Miners don't do well when ambient air drops below 32F because of heat stresses across the board from one end to the other.  Too much temperature gradient.

What to mine next?  I mined a lot of Ethereum and ZCash with these cards, mostly R9-390's.  I have sold probably 30 of these and more for sale now.

I don't have power going to a single R9-class card at this time.

Thermodynamics.

Temp sensors are at one end.  Blow cold air onto them they read cool.  The entire system is getting hot, but the system is not aware.

The engineers who design and build these things are not idiots.

Tariffs affect everything made in China.  Yes, AMD and NVidia are US companies.  The cards built with their products are built in China.  The GPU chips are mad in Taiwan or China.  The rest of the components are made in China.  If you're in USA, tariff applies to you.  And me.

OK to drive multiple things from one PSU.  (Think of your house - 1 PSU for your whole city)

Don't mix PSUs on a single device.

I have an IBM 2880 watt server PSU and running 4 Minis off of it.  Previously running 2x S9's off of it.

Bitmain is a billion-dollar company in the PRC.  There's no chance that anyone can do anything to them. 

Does anyone have the timestamp of the cgminer.conf file and the /config directory from stock on September batch?   

I have a unit which is reporting oxoo on one of the boards, and need to restore back to original configuration before shipping it in.

Thanks!

Good list, even if it is numbered.

The only thing I would add is to do the math on mining.  Straight up power cost vs. coins produced, independent of capital invested.  If you can buy coins cheaper with electricity, then mine.  If you cannot, then invest in coins.  If you're mining for short term profit, then you're in a different game than me.

I've mined off and on since 2013.  Never sold a coin.  Converted to other coins, or traded coins for miners, but money goes in and never comes out.  Coins for miners is probably one of the worst investments I ever made.  If I had bought coins with fiat and used that for miners, then it would have been a better deal. 

Hindsight is a fun game.  Especially in this market.

So many unknowns, so much is un-knowable.
- I was in your exact position earlier this year.  I had rented 1000 Square feet in Texas, and had 100KW of 3-phase power available immediately and plans for more.
- As crypto dropped, I abandoned my plans, started selling my gear (still have a bunch) and shut down the facility. 
- I am converting cash into crypto rather than rent, and mining at home only, using only Z9-mini's.  All GPUs are shut down, and all S9's are shut down.

So what do we know?
- Hash rate of every worthwhile coin is the one thing that is actually mooning.
- Bitmain prices their products for ~1 year ROI, maybe a bit less.  In my experience, Antminer S-series will pay back 1X in a year, and never pay another 1X because of hashrate growth.
- Rising value of Crypto to Fiat, makes all of the above math look better than if it stays flat.
- Of course something new is coming from Bitmain.  S9 series is more than 2 years old.  It's time.

What can we do?
- Assume crypto is going to moon.  Buy Crypto because you can't mine crypto as fast as you can buy crypto.
- Assume crypto will drop.  Sell what you have and be done with it.
- Assume crypto will be flat.  Maybe mine if your costs are low enough, but need to recognize that you're in a declining return over time because of hashrate growth.

What should you do?  Be careful.  Even at 5.5 cents/kWh, be aware you're competing with people in China and other parts of the world who are paying much less or even not paying for their power. 

Why not just use the Bitmain model and mine on your own?

Fake wallet address sends mined coins to fake address that can never be recovered.  Why do this?  I have 2 Z9's on Flypool and setup is exactly as stated above.  t_address is "don't use a z_address"  All ZCash transparent addresses start with a t.  Only transparent addresses are supported by mining pools.

Can't wait!

Overwinter does not affect the mining algorithm.  Z9's are powering on.

What's your ambient temperatures?  I'm running a lot warmer at 650MHz.  But Ambient is about 100F.

3rd pool?  Why does this even matter?  This is your 2nd backup.  If Pool 0 is not responding, it tries Pool 1.  IF that one fails, then Pool 2 (third one) comes into play.  99.99% of your traffic should be going to Pool 0, and 0.0000001% might go on Pool 2.  Unless you have pools with problems.  Then you need a different pool.

Flypool - I had used Flypool about a year ago and had a tiny residual balance there, so I pointed the Z9 over there and we're off to the races.  Cranking out shares!!


I did some digging in the history of CGMiner - My interpretation of that discussion is that Discarded shares are shares that were "scheduled" to be run, but were discarded because pool provided new work.  According to the earlier discussion, these do not represent any lost work.  

I'll take a look when I get back to the miner.  Thanks!!

I am getting huge numbers of rejected/discarded shares on both Slushpool and on Nanopool, and no hashrate is reported on either pool.  Tried for over an hour on each pool.

I've mined ZCash on GPUs on both of these pools since the first day that GPU miners were available and both have been rock solid.

Are others able to run Z9 on either of these 2 pools?  Should I choose a different pool for running ASIC?

(I'm a "newbie" because my account got hacked and I locked it.  Never bothered to go thru the recovery process.)