Hugo Mills posted on Tue, 24 Nov 2015 21:27:46 +0000 as excerpted: [In the context of btrfs send...]
> -p only sends the file metadata for the changes from the reference > snapshot to the sent snapshot. -c sends all the file metadata, but will > preserve the reflinks between the sent snapshot and the (one or more) > reference snapshots. You can only use one -p (because there's only one > difference you can compute at any one time), but you can use as many -c > as you like (because you can share extents with any number of subvols). > > In both cases, the reference snapshot(s) must exist on the > receiving side. > > In implementation terms, on the receiver, -p takes a (writable) > snapshot of the reference subvol, and modifies it according to the > stream data. -c makes a new empty subvol, and populates it from scratch, > using the reflink ioctl to use data which is known to exist in the > reference subvols. Thanks, Hugo. I had a vague idea that the above was the difference in general, but as CAM says, the manpage (and wiki) isn't particularly detailed on the differences, so I didn't know whether my vague idea was correct or not. Your explanation makes perfect sense and clears things up dramatically. =:^) -- Duncan - List replies preferred. No HTML msgs. "Every nonfree program has a lord, a master -- and if you use the program, he is your master." Richard Stallman -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
