From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from plane.gmane.org ([80.91.229.3]:59359 "EHLO plane.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751309AbbKZPpK (ORCPT ); Thu, 26 Nov 2015 10:45:10 -0500 Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1a1yjI-0002us-Pm for linux-btrfs@vger.kernel.org; Thu, 26 Nov 2015 16:45:04 +0100 Received: from ip98-167-165-199.ph.ph.cox.net ([98.167.165.199]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 26 Nov 2015 16:45:04 +0100 Received: from 1i5t5.duncan by ip98-167-165-199.ph.ph.cox.net with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 26 Nov 2015 16:45:04 +0100 To: linux-btrfs@vger.kernel.org From: Duncan <1i5t5.duncan@cox.net> Subject: Re: btrfs send reproducibly fails for a specific subvolume after sending 15 GiB, scrub reports no errors Date: Thu, 26 Nov 2015 15:44:59 +0000 (UTC) Message-ID: References: <56530608.50906@gmail.com> <20151123211012.GA12286@ny.voidptr.de> <56545C1B.1080507@gmail.com> <1448390914.21291.42.camel@scientia.net> <5654CC1B.4030209@gmail.com> <1448398257.21291.63.camel@scientia.net> <5654CF58.8080207@gmail.com> <1448399833.21291.84.camel@scientia.net> <20151124212746.GS24333@carfax.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: 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