[Solved] How to upgraded without re-downloading blocks

[d4n13]

Upgrading from bitcoin-qt 0.8 to bitcoin-xt 10.1.

My plan is as follows:
1) backup my blocks directory
2) backup my wallet.dat
3) download bitcoin-xt
4) go offline
5) install bitcoin-xt
6) from command line launch bitcoin-xt with following parameters
6a) -checklevel=0 -checkblocks=1 -splash=0 -listen=0 -rescan -reindex

My questions:
a) is this grossly over simplified?
b) are bitcoin-qt 0.8 and bitcoin-xt 10.1 even remotely compatible?
c) is there actually a better / simpler way to try this?
d) in {6} would it be better to do bitcoind and query where the rescan reindex
e) have any of the 3000 xt full node ops ever tried anything like this before?

Thx

[unamis76]

I haven't yet installed XT, but as it says on their github, XT and Core are compatible. So you just run XT instead of Core and you should be good to go But yeah, it's a safe bet to back up everything

[d4n13]

b) are bitcoin-qt 0.8 and bitcoin-xt 10.1 even remotely compatible?

I haven't yet installed XT, but as it says on their github, XT and Core are compatible.

OK... so I guess a corollary question would be:
b1) are bitcoin-qt 0.8 and bitcoin-qt 10.1 even remotely compatible?

I'm concerned with both the question of whether the *.blk file archival format has changed from 0.8 to 10.0 as well what the *.blk archival format is between qt and xt.

Same goes for wallet.dat.

Just read https://bitcoin.org/en/release/v0.10.0, and now it looks like there are some blk file format differences that could send me in a tailspin.  I'm not sure I buy the 3hrs to full sync.  Took me 3 weeks to bring 0.8 back to sync, but if the torrent works, I'll just try that.

Thx.

[d4n13]

...but if the torrent works, I'll just try that.

Bust! the torrent is no longer maintained.

If plan A doesn't work, then I need to manually linearize a bootstrap.dat file then try loading it that way:
https://github.com/bitcoin/bitcoin/tree/master/contrib/linearize

We'll see.

[unamis76]

0.8 and newer versions are compatible. The only thing between them is the fact that the blockchain has to be reindexed, because the format used to keep the database has changed in newer versions

The torrent is no longer maintained, because it's irrelevant, it does not make blockchain indexing faster anymore, as the new versions use a different form of syncing that's quite faster...

[d4n13]

0.8 and newer versions are compatible. The only thing between them is the fact that the blockchain has to be reindexed, because the format used to keep the database has changed in newer versions

The torrent is no longer maintained, because it's irrelevant, it does not make blockchain indexing faster anymore, as the new versions use a different form of syncing that's quite faster...

So in your opinion would copying an 0.8 blocks directory to an 0.10 install be problem free?

I understand that going the other way round is forbidden.

[unamis76]

0.8 and newer versions are compatible. The only thing between them is the fact that the blockchain has to be reindexed, because the format used to keep the database has changed in newer versions

The torrent is no longer maintained, because it's irrelevant, it does not make blockchain indexing faster anymore, as the new versions use a different form of syncing that's quite faster...

So in your opinion would copying an 0.8 blocks directory to an 0.10 install be problem free?

I understand that going the other way round is forbidden.

Yes, it should be problem free. I've upgraded nicely from 0.9 to 0.10, it shouldn't be much different from 0.8 to 0.10. There is no database structure differences from 0.8 to 0.9 as far as I know

The other way around is forbidden, yes. You have to have a backup of the "old" blockchain to be able to use 0.8 again.

[PolarPoint]

I think the sure way is to upgrade to Core QT 0.10 first. Let QT upgrade and reindex the block data, then switch over to XT.

[d4n13]

too late... pulled the trigger.  Came up in seconds and banged on the disk for about 10 minutes, now it's all quite.

Actually what I did was this:
1) Move Blocks dir off of drive C:
2) Replace the whole in AppData with a symlink
2a) mklink /d "%appdata%\Bitcoin\blocks" "<otherdrive>\<otherdir>\blocks"
3) Run bitcoin-qt(xt) with parameters
3a) start /low "" bitcoin-qt.exe -checklevel=0 -checkblocks=1 -splash=0

Tada