Hey all,
Newbie here.
Fired up a cpu miner a day ago. All seems to be working well, I am able to find shares.
My question is where are these stored? Because they don’t show up in the wallet (zero balance).
If I kill the miner/node and run it again - are the shares I find stored somewhere?
Shares go to the pool which stores your rewards, or if you’re talking about finding solutions and not shares then you’ll have to wait until you find a block.
Shares don’t matter when mining against your local node (a.k.a. solo mining). Either you solve a block or you don’t. It is not like one accumulates 10,000 shares and then is given the block reward.
and to solve/find a block your share difficulty should be equal or higher then the given block’s difficulty.
let’s assume there are more then 500k GPUs involved in grin mining…
the “share” what solves the block is submitted only by one GPU (unlikely CPU).
in other words, n-1 (GPU/CPU) just wasted the electricity and produced heat. that’s how PoW mining works 
unless you have a ton of hashpower, which i assume you don’t. You should find a pool to mine at, share the work, share the rewards. You could be waiting a looong looong time for any payout, solo-miming.
If you have only one CPU?