Topic: My Bitcoin-QT blockchain died. (Read 6903 times)

Okay, I've had the blockchain back for a week or so.  My Win7 machine has started locking up.  My C: drive is 2TB, backup on another drive.  I see I have used up most of C since starting to rebuild the blockchain with many restarts.  Are there duplicate blocks from earlier attempts that I may delete?

So, I went back to unpruned mode, recrunching the whole 9 yards, and was quite far along on Thursday but it was raining.  So, I shut it down rather than chance a power outage.  Then I left it down until Monday, today, because I always back up my systems on Saturday and also that most failures have occurred on Fri, Sat or Sun.  Today I needed to do some shopping and started Bitcoin-QT before I left.  A cell passed through and when I came back in my systems were down.

I fired them up.  Starting Bitcoin-QT, it went through a check and then said Bitcoin Core not responding.  I just let it set.  Lo and behold, a few minutes later it opened and commenced processing blocks where it left off.  I'm happy.

I wonder.  The many times I've restarted from scratch this year, are there old blockchains abandoned and taking up space?

soy

"You need to rebuild the database using -reindex to go back to unpruned mode.  Do you want to rebuild the block database now?"  So, from 1 year some months to go, it's back to 4+ years. ...my mistake, 8 years 10 weeks behind....

Well, turning pruning on didn't cause a restart.  I'll try stopping and starting without pruning now because if what you say is correct, I don't want to lose the blockchain at the end were I to go to no pruning then.  Although I can see that if one has already deleted a large part of the blockchain then yes, that would have to be downloaded with pruning off.

No, it picked up where it left off, 2+ years to go.  So, the probability that the whole blockchain must first be downloaded before pruning starts is high.

I've torrent downloaded the blockchain before and built from that but it didn't seem any faster.

With only a month or two to go when it almost finished the other day, all those blocks, reindexing seems not to use those but downloads new or am I mistaken?

Yes, I know for a fact that you will have to re-download the entire blockchain if you turn off pruning.

I'm not certain, but I suspect that once you have pruning turned on, it may start over downloading from the beginning again if you turn it off (since those early blocks may already have been pruned).

Correct.  You'll still need to download the entire blockchain, and it won't speed up the process. It will just delete the completed work as new blocks are added to the other end, so it will use less drive space.

It doesn't wait until the entire blockchain has been downloaded and stored on the drive before it starts pruning the completed stuff.

Hey, just thought of something. Sometimes malicious users will insert viruses or malware in the blockchain. Perhaps you are getting some of that crap and your anti-virus is flagging it and causing the Core node to stop syncing.
Not sure how Core or AV applications handle that.

I do recall I had to allow an exception for QT through my firewall port. But I have other apps that will prevent any malicious code from running. Anyway, from what I understand, malicious code in the blockchain can't infect your machine.

Just an idea. 

Also, if you haven't already done so, I would suggest reading this page https://bitcoin.org/en/full-node# and see if  there is anything that you are overlooking or answers to possible problems.
Good luck!

If there was a way and I knew how to do it, I'd let you sync off my blockchain. I usually always have 20-30 peers syncing, giving to and taking from my blockchain. I have no issues with network traffic.

I agree.  And since drive space isn't an issue, 2TB drive, next time it shuts down I'll restart without the -prune.  The prune switch seems to make no difference in network traffic judging by a glance at the debug network traffic.

That's what I was thinking, that you have to download the data in order to get to the last 550MB. Else how would it know that it is only going to keep approximately the last 2 days worth of the blockchain. It may discard all the data up until the last few days, but it still - in my thinking - has to go through the previous data.

From my understanding, a pruned node is not considered a full node and is unable to serve up historical blocks to other nodes. "Keeping all blocks is a service to the network, as you'll be able to provide all blocks for synchronizing nodes or requests of thin clients."

However it works and whether it will take just as long to get it downloaded and pruned or not, good luck with it.

To be honest I'm skeptical.  So prune=550 will only keep about 2 days of the blockchain on he drive.  At 2 years 4 weeks behind I suspect all this does is chop off work that has been completed while new stuff is added to the other end.  No difference in the time it should take to get a functioning wallet.

Okay, thanks.  I had been having problems with Google Calendar opening by Task Scheduler in the mornings.  Yesterday I unscheduled it.  Should have had an easier time but when I got on this AM there was the BSOD.  Perhaps because I failed to close Google News last night.  Restarted today and thankfully it went back to processing at 2 years 4 weeks behind.

So, it is possible to prune before the chain finishing?  I'll give it a try.  Thanks.

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Thanks for clarification. As I said, I didn't know too far!
I have always had the full blockchain and never have pruned it or needed to. So I was assuming that you must have the entire blockchain available before you are able to prune it.
I stand corrected. (Which is quite often! )

I haven't experienced the difficulties you describe, even with unexpected and uncontrolled shutdowns. Perhaps you should consider shutting down and creating a backup of the blockchain regularly. That way if you have a crash again you can restore and not have to start from the beginning again.


Everyone that doesn't lose their bitcoins.  The exchange rate between bitcoins and anything you may want to exchange them for depends on the supply of those bitcoins and the demand for them.  If bitcoins are permanently lost, then the supply shrinks. This drives the exchange rate up at any given demand to maintain balance.


More likely than not, the block they were working on was unsolvable.  Most blocks that most miners are working on are.

Another way to look at it is that EVERY hash is effectively a brand new block. Therefore there are 0 blocks ever "aborted" (aside from computer crashes that prevent the completion of computing a single hash).


Yes.


It's open source.  There's nothing preventing you (or anyone you hire) from doing a better job if you don't like the job the current participants are doing. The software is free.  You've gotten more than you paid for.  If you've chosen to exchange cash for bitcoins, then can I suggest caveat emptor.


This is not true.  Pruning occurs as the blockchain downloads.

No, the full Core node doesn't have the capability of mining anymore. Not sure of what version that was taken out. It was before my time in Running a Core full node.
Best wishes!

No, not as far as I know (which isn't too far! LOL)
You must download the entire blockchain before you are able to prune it.

I've been running Core and wallet 13.0 / QT 5.6.1 on an HP laptop with two 1 terabyte disks and 16GB RAM for many months. It is all fed from my network which includes other laptops, all television, and four S9 miners, three S7 miners over GB modem/router/switches. My download speed from cable provider is 60MG/s. Not sure of upload. But I usually always have at least 20-30 peer connections.

I've had no problems after the initial download except once when the db became corrupted for some reason - probably Windows update. (Running Win10, which I have grown to dislike very much!)
The blockchain repaired itself in about a day and a half.

As mentioned before, whatever browser you are using has absolutely no effect on the Core/QT application, its installation and syncing up with the complete block chain.

If you are still having problems, stop all other tasks or application on the PC in question and don't surf the web while downloading the blockchain.

Not sure if I'm replying to the right person as I have a slight buzz from watching NCCAA Basketball all day long. (My Gamecocks are still in it!) 

Best of luck with getting your Core up and running!!! 

Anyway to set this Bitcoin-QT to nothing in nothing out until at least it's up to its last previous state, around Feb. of this year?  It feels like I'm getting exploited to hell with gigabytes out and unnecessary repeats of 4 years worth of blocks to check.

One thing is for sure.  This Bitcoin-QT is about as far from eco-friendly as it can get.  Wasted energy.  btc=$946 and falling.

So, my Bitcoin-QT started again, I look some hours later and although last I looked it was down to 3 years, it was back to processing blocks on disk 4 years 25 weeks.

I understand pruning is now possible.  Is it possible to prune before the entire blockchain is downloaded?  I'm surprised some developers of this pos haven't been taken behind the stores and stomped.