I'm currently installing Mist/Ethereum Wallet from the pre-built binaries.

Having the run the ./Ethereum-wallet executable, it's now part-way through syncing the blockchain. It seems to be taking quite a while, so I'm assuming it's a full sync, rather than a fast one. However, I'm unsure about this and want to find out for certain.

It doesn't appear to be possible to geth attach to the node that the Wallet has started in the background, so I have no visibility into what's going on, and can't use the console logs as a way to determine which type of sync is happening. [See "Console message difference between --fast and normal syncing", here.]

So my question is as follows:

In the absence of console logs, is there a way to tell from the chaindata/ itself whether fast or full sync is occurring?

  • AFAIK, Mist doesn't give you the option to fast sync, so it's almost certainly doing a full sync – Tjaden Hess May 3 '16 at 13:46
up vote 9 down vote accepted

EDIT: fast mode is now the default mode for Geth.

You can change the mode using the --syncmode parameter.

--syncmode "fast" Blockchain sync mode ("fast", "full", or "light")

See Command line options documentation in ETHEREUM OPTIONS section or run geth help.

To check a running node mode, on *nix systems like Linux or OSX, you simply have to run the following in a terminal :

ps ux | grep geth

And the result should be something like that:

myuser 15745   2,3  3,2 573464180 530888   ??  S     1:16     0:38.72 /Applications/Ethereum-Wallet.app/Contents/Frameworks/node/geth/geth --fast --cache 512

Indicating your node is running in default mode which is fast mode.

or

myuser 15745   2,3  3,2 573464180 530888   ??  S     1:16     0:38.72 /Applications/Ethereum-Wallet.app/Contents/Frameworks/node/geth/geth --syncmode fast --cache 512

If you explicitely indicated the fast mode using the --syncmode parameter.

If you run Windows you can have a look to this answer : https://superuser.com/questions/415360/how-do-i-find-out-command-line-arguments-of-a-running-program that shows the options passed when the app was started. But I don't have a Windows PC to check this answer, so take it with caution.

But in any case, remember, fast means sync in some hours or a day and full sync can take many days. So don't expect your wallet to sync in a few minutes even if you have a huge internet connection, it's still limited by what pears can do.

  • What if I don't know how big the two sets of data are? For example, if I'm reading this in the future when the sizes are different to those you've referenced? And what if my sync hasn't finished yet and is still below 3GB? In that case I could be partway through either a full or fast sync. – Richard Horrocks May 3 '16 at 10:58
  • Edited, but sorry to have only a poor answer for windows machines. – Nicolas Massart May 3 '16 at 11:30
  • 2
    This (good) answer needs updating. – Madbreaks Nov 9 '17 at 20:38
  • 1
    @Madbreaks right, --fast is deprecated. Now you have to use --syncmode "fast" Blockchain sync mode ("fast", "full", or "light") Fast is the default mode now. I'll edit the answer. – Nicolas Massart Feb 19 at 13:07

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