replication & pruning: ditch replicated-property, use bookmark as cursor instead

A bookmark with a well-known name is used to track which version was
last successfully received by the receiver.
The createtxg that can be retrieved from the bookmark using `zfs get` is
used to set the Replicated attribute of each snap on the sender:
If the snap's CreateTXG > the cursor's, it is not yet replicated,
otherwise it has been.

There is an optional config option to change the behvior to
`CreateTXG >= the cursor's`, and the implementation defaults to that.

The reason: While things work just fine with `CreateTXG > the cursor's`,
ZFS does not provide size estimates in a `zfs send` dry run
(see acd2418).
However, to enable the use case of keeping the snapshot only around for
the replication, the config flag exists.

This commit is contained in:

Christian Schwarz

2018-09-05 18:24:15 -07:00

parent acd2418803

commit 975fdee217

9 changed files with 559 additions and 294 deletions

									
										config/config.go
									
		+1
		
												View File
												
				@@ -205,6 +205,7 @@ type PruningEnum struct {

				type PruneKeepNotReplicated struct {

					Type string `yaml:"type"`

					KeepSnapshotAtCursor bool `yaml:"keep_snapshot_at_cursor,optional,default=true"`

				}

				type PruneKeepLastN struct {