From 33c949697e316f17bb5037ae83509f35ce28f6a9 Mon Sep 17 00:00:00 2001 From: Dimitri John Ledkov Date: Tue, 26 Jul 2016 13:30:05 +0100 Subject: New upstream release --- Documentation/btrfs-send.asciidoc | 49 +++++++++++++++++++++++++-------------- 1 file changed, 31 insertions(+), 18 deletions(-) (limited to 'Documentation/btrfs-send.asciidoc') diff --git a/Documentation/btrfs-send.asciidoc b/Documentation/btrfs-send.asciidoc index e05342ff..47b0b047 100644 --- a/Documentation/btrfs-send.asciidoc +++ b/Documentation/btrfs-send.asciidoc @@ -3,7 +3,7 @@ btrfs-send(8) NAME ---- -btrfs-send - send data of subvolume(s) to stdout/file. +btrfs-send - generate a stream of changes between two subvolumes SYNOPSIS -------- @@ -11,40 +11,53 @@ SYNOPSIS DESCRIPTION ----------- -Sends the subvolume(s) specified by to stdout. - should be read-only here. -By default, this will send the whole subvolume. To do an incremental -send, use '-p '. +This command will generate a stream of instructions that describe changes +between two subvolumes. The stream can be consumed by the *btrfs receive* +command to replicate the sent subvolume on a different filesystem. +The command operates in two modes: full and incremental. -If you want to allow btrfs to clone from any additional local snapshots, -use '-c ' (multiple times where applicable). +All subvolumes involved in one send command must be read-only (ie. the +read-only snapshots and this status cannot be changed if there's a running send +operation that uses the subvolume). -You must not specify clone sources unless you guarantee that these snapshots -are exactly in the same state on both sides, the sender and the receiver. +In the full mode, the entire subvolume data and metadata will end up in the +stream. + +In the incremental mode (options '-p' and '-c'), there can be one or more +parent subvolumes that will establish the base for determining the changes. +The final stream will be smaller compared to the full mode. It is allowed to omit the '-p ' option when '-c ' options are given, in which case *btrfs send* will determine a suitable parent among the clone sources itself. +You must not specify clone sources unless you guarantee that these snapshots +are exactly in the same state on both sides, the sender and the receiver. + `Options` --v:: -Enable verbose debug output. Each occurrence of this option increases the -verbose level more. -e:: -If sending multiple subvols at once, use the new format and omit the between the subvols. +if sending multiple subvolumes at once, use the new format and omit the +'end cmd' marker in the stream separating the subvolumes -p :: -Send an incremental stream from to . +send an incremental stream from 'parent' to 'subvol' -c :: -Use this snapshot as a clone source for an incremental send (multiple allowed). +use this snapshot as a clone source for an incremental send (multiple allowed) -f :: -Output is normally written to stdout. To write to a file, use this option. -An alternative would be to use pipes. +output is normally written to standard outout so it can be eg. piped to +receive, use this option to write it to a file --no-data:: -Send in NO_FILE_DATA mode. The output stream does not contain any file +send in 'NO_FILE_DATA' mode ++ +The output stream does not contain any file data and thus cannot be used to transfer changes. This mode is faster and useful to show the differences in metadata. +-v|--verbose:: +enable verbose output, print generated commands in a readable form, (each +occurrence of this option increases the verbosity level) +-q|--quiet:: +suppress all messagese except errors EXIT STATUS ----------- -- cgit v1.2.3