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CDC File Transfer

github.com

51–60 of 229 posts

Re: CDC File Transfer

#51

I took a quick glance at the repo, it wasn't totally clear to me if the client is windows only. Anyone know more?

I imagine that one could develop this further into both ends being cross-platform but the readme seems to really strongly define it is solely built to transfer files from Windows to Linux. If that's all you need for internal tool, that's all you build (and test).

Re: CDC File Transfer

#53
post #35

sounds like cdc_rsync should be a good replacement for rsync in a generic backup

Imagine an rsync that was A LOT smarter for backup use cases. Detecting files that have been renamed, files that have been compressed, similar files, files that have only been appended to, files that are the same across multiple systems (Oh, yeah, I probably already have a copy of this kernel file from this other host). Basically, deduplication as part of rsync.

Re: CDC File Transfer

#54
Comparing it with rsync running on Cygwin is a bit unfair, as Cygwin is known to be terribly inefficient. I don't doubt that their CDC based algorithm is faster, but probably not by the margin they claim if Cygwin is taken out of the equation

Re: CDC File Transfer

#55

Earlier quoted context omitted.

Google / abc has a solid track record of open sourcing shutdown projects. See Makani[1] and iirc also Loon. [1] https://news.ycombinator.com/item?id=24456613

Another example is Google Wave, which was also open sourced after it was shut down. https://en.wikipedia.org/wiki/Google_Wave https://incubator.apache.org/projects/wave.html Apache Wave was retired in 2018, but the source remains at least.

Always nice to see my old work pop up! I'm really proud to have worked on the team that opensourced wave!

Re: CDC File Transfer

#56

With a small bit of tweaking this could be used for syncing live SQLite databases (probably)

The problem is conflicts. If two remote peers both edit data concurrently, its not obvious what the resulting sqlite state should be.

Better to embed a CRDT inside sqlite that can understand the semantics of sqlite's data, like cr-sqlite is doing:

https://github.com/vlcn-io/cr-sqlite

Re: CDC File Transfer

#57
I'm really impressed with the readme file in this repository. Its a master class in effective documentation. Just look at the structure:

- 1-2 sentence summary of the project

- History (why we built this and didn't just use existing tools)

- What we've built, including what it does and how it compares to other tools (rsync in this case).

- How to install and use it

And the whole thing is full of images and animations showing the tool in action, and explaining enough of its internals.

I consider myself good at documentation, but I'm taking notes. This is excellent.

Re: CDC File Transfer

#58
post #41

Content Defined Chunking is one of my favorite algorithms because it has some "magic" similar to HyperLogLogs, Bloom filters, etc... This algorithm is good to explain to people, to get them inspired by computer science. I usually explain the simplest variant with rolling hashes. It is interesting what the result will be (average saving on deduplication) if it is applied globally to a large-scale blob storage, such as…

> It is interesting what the result will be (average saving on deduplication) if it is applied globally to a large-scale blob storage, such as Amazon S3 or Google Drive (we need metadata storage about chunks, and the chunks can be deduplicated). Yes this is truly promising but beware of dragons. Under current legal doctrine, blobs need some form of chain of custody. You can’t just deliver chunks to whomever has a has…

Isn't the main use of bittorrent for ML and research data? Academic torrents is a wonderful resource and what every developer should be using if they need to provide their neural network weights, training data, etc. How is there any legal problem using bittorrent? It's simply much more tailored for this problem than http. It doesn't make any sense to talk about 'Legal problems' for torrent protocols.

Re: CDC File Transfer

#60
post #45

> However, this was impractical, especially with the shift to working from home during the pandemic with sub-par internet connections. scp always copies full files, there is no "delta mode" to copy only the things that changed, it is slow for many small files, and there is no fast compression. I didn't appreciate the scope of this problem until a friend of mine visited from the valley. I live in semirural Canada, and…

> I sort of took it for granted that people would spend the extra twenty bucks or so to make work from home a painless experience I think you took for granted the mere availability of fiber as an option. 30Mbps DSL is the best option I have, other than Starlink. And I live in San Jose!

You're not wrong. It's amazing how poor access can be.

I live in a tiny town on Vancouver Island and I have gigabit symmetric, for a very reasonable price. When I lived in Vancouver that simply wasn't an option.

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