dumb question from noob here. I have started to sync with command geth --fast --cache=1024 for more than 3 days now, and I am still not finished syncing yet (still around 1 million again). Somehow I sense that my internet connection is getting slower with each day and I am wondering if I reboot my router it can help speed things up again. So my questions are: Is my internet get slower because of the sync process (my connection is in more than 30++ billion bytes); if I reboot my router (not closing the console with geth process) in hoping that it can help speeding things up again (maybe it will clear the router cache, etc) do I need to redo my sync again? Thanks for anyone who try to help, just completely confused now.
...if I reboot my router (not closing the console with geth process)
If you want to do this, ensure that you stop the
geth process first, then reboot your router. If you reboot your routing while geth is running, there's no guarantee you'll invoke any of its signal handing to close gracefully. This could result in a corrupt database.
...do I need to redo my sync again?
No, as long as
geth was closed cleanly, it will just pick up from where it left off. (This particular question has been asked before, though I can't find the link to it.)
If you close geth and start it, it will not restart in --fast mode. That can only be done the first time.
I would restart the router without restarting geth, but at the same time, it's very unlikely that the router is the source of the problem.
You can consider either just leaving it running until it's done or use a website like myetherwallet.com which doesn't require the user to download the blockchain but still provide them with the private keys.