On Monday, January 25, 2016 01:03:17 PM Wladimir J. van der Laan wrote: > > If yes, I would highly recommend advertising it in the new release notes - > > as said, the disk space reduction is a big deal. > > Good idea, has been added by Marco Falke in commit fa31133, Thanks. The RC2 changelog now says: > To enable block pruning set prune= on the command line or in > bitcoin.conf, where N is the number of MiB to allot for raw block & undo > data. From having read the Bitcoin whitepaper quite a few months ago ago, I have the very very basic understanding that pruning is meant to: - delete old transaction data which merely "moves coins around" - instead only store the "origin" (= block where coins were mined) and "current location" of the coins, i.e. the unspent transactions. Notably, I understood it as "this is as secure as storing everything, since we know where the coins were created, and where they are". So from that point of view, I would assume that there is a "natural" amount of megabytes which a fully pruned blockchain consists of: It would be defined by the final amount of unspent coins. I thereby am confused why it is possible to configure a number of megabytes "to allot for raw block & undo data". I would rather expect pruning just to be a boolean on/off flag, and the number of megabytes to be an automatically computed result from the natural size of the dataset. And especially, I fear that I could set N too low, and as a result, it would delete "too much". I mean could this result in even security relevant transaction data being deleted? Thus, it would be nice if you could yet once more edit the release notes to: - explain why a N must be given - what a "safe" value of N is. I.e. how large must N be at least to not delete security-relevant stuff? - maybe mention if there is a "auto" setting for N to ensure that it choses a safe value on its own? Sorry if my descriptions are from a layman's point of view. I intentionally did *not* re-read the Bitcoin whitepaper to have a better understanding: I think having a layman's understanding is a good usability test for such stuff.