Difficulty syncing

I run the datacenter. I can assure you, my traffic is not throttled.

…well, that answer that!

For comparison I restarted an old node so it can catch up, downloads peaking at 37Mb & that’s on a crappy Celeron CPU (8Gb RAM).

I took another machine, with 4-cores (original just had one CPU), and I was able to sync the entire thing in 8 hours.

But…then I stopped things, I put in my wallet.dat, and started them again, and now it is 'Init message: Rescanning…" on the splash screen. The logs show:

2019-01-31 12:59:10 Rescanning last 434481 blocks (from block 36241)…

hours later…

2019-01-31 18:07:08 Still rescanning. At block 38257. Progress=0.028852

its running the fans loud on the machine, mining is still not on. This looks like it will take several days. Its stuck around 38k out of 430k. Its been running 6 hours and 21 minutes.

It moves about 20 blocks per minute.

I don’t understand what it is doing, I already downloaded the full block chain.

I just want to see my balance :frowning:

Only idea I have is if there are lots of zaddrs in that wallet, and I mean LOTS… each one would require a full scan to determine its state/balance.

Anyone else…?

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That could be, at one time I was generating unique ones for a web payment form, before I realized that they didn’t need to be unique.

I guess you’ll just have to wait & see if that was the problem. Consolidate your funds on a new node/wallet when the old node has fully synced, otherwise you’ll have to do this all over again.

Let us know how it goes, curious how many zaddrs there are on the old node.

Yes, quite possible. I also think so.

This indeed does sound like a case of many zaddrs slowing down the process. Unfortunately this hasn’t been optimized much yet. There are issues related to having a lot of taddrs but not many services create many zaddrs so there aren’t any previous reports. Please file a new issue here: Sign in to GitHub · GitHub

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Can I increase the number of threads used for script verification:

2019-02-06 23:56:47 Using 4 threads for script verification

Otherwise, this will take 45 days at this rate.

There are some zcashd options that might help speed things up (I’ve not used them myself)

-par=
Set the number of script verification threads (-2 to 16, 0 = auto, <0 =
leave that many cores free, default: 0)

-dbcache=
Set database cache size in megabytes (4 to 16384, default: 450)

Maybe some more things you can try, ‘zcashd --help’ for the full list of options.

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@raaah: I created this issue Slow syncing/rescanning for wallet with many z-addrs · Issue #3834 · zcash/zcash · GitHub

Could you provide any other information that you come across in that ticket so the dev team can investigate?

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yup i’ve had the same issue.

syncing from scratch with a wallet.dat with about 130000 bytes.

I found a list of active nodes on a block explorer and tried connecting to them one by one to see if its the nodes internet connection that’s throttled, and did have minor success getting a quick 10% synced… but then it slowed again.

-par=16 and -dbcache=8192

often stalls and a ctrl-c and restart regains the momentum but its a constant battle.

25% after almost 48 hours.

Hello
I had Jaxx Classic wallet and Zcash there
Several days ago Jaxx released its new wallet Jaxx Liberty and told me to sync this wallets (Classic and Liberty) to make me able to manage my Zcash
Give me please an advise what new wallet to use and how to send my Zcash there if a know this 12 words password key