diff options
| author | Christian Schwarz <[email protected]> | 2017-05-10 00:36:53 +0200 |
|---|---|---|
| committer | Brian Behlendorf <[email protected]> | 2017-05-09 15:36:53 -0700 |
| commit | 305bc4b370b20de81eaf10a1cf724374258b74d1 (patch) | |
| tree | c03a347aab95d2606b24faf389b0a9e842081dd6 /man/man8/zfs.8 | |
| parent | 78d95eaa732f074a6351045e59cd974380ad50ab (diff) | |
Make createtxg and guid properties public
Document the existence of `createtxg` and `guid` native properties
in man pages and zfs command output.
One of the great features of ZFS is incremental replication of
snapshots, possibly between pools on different machines.
Shell scripts are commonly used to auomate this procedure. They have to
find the most recent common snapshot between both sides and then
perform incremental send & recv.
Currently, scripts rely on the sorting order of `zfs list`, which
defaults to `createtxg`, and the assumption that snapshot names on
either side do not change.
By making `createtxg` and `guid` part of the public ZFS interface,
scripts are enabled to use
a) `createtxg` to determine the logical & temporal order of snapshots
(the creation property is not an equivalent substitute since
multiple snapshots may be created within one second)
b) `guid` to uniquely identify a snapshot, independent of its current
display name
This has the potential of making scripts safer and correct.
Reviewed-by: George Melikov <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: DHE <[email protected]>
Reviewed-by: Richard Laager <[email protected]>
Signed-off-by: Christian Schwarz <[email protected]>
Closes #6102
Diffstat (limited to 'man/man8/zfs.8')
| -rw-r--r-- | man/man8/zfs.8 | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/man/man8/zfs.8 b/man/man8/zfs.8 index 672079637..5d0b79b99 100644 --- a/man/man8/zfs.8 +++ b/man/man8/zfs.8 @@ -441,6 +441,18 @@ For non-snapshots, the compression ratio achieved for the \fBused\fR space of th .sp .ne 2 .na +\fB\fBcreatetxg\fR +.ad +.sp .6 +.RS 4n +The transaction group (TXG) in which the dataset was created. Bookmarks have the same \fBcreatetxg\fR as the snapshot they are initially tied to. +.sp +\fBcreatetxg\fR is suitable for ordering a list of snapshots, e.g. for incremental \fBsend\fR & \fBrecv\fR. +.RE + +.sp +.ne 2 +.na \fB\fBcreation\fR\fR .ad .sp .6 @@ -488,6 +500,18 @@ been set somewhere in the tree under which the dataset resides. .sp .ne 2 .na +\fB\fBguid\fR +.ad +.sp .6 +.RS 4n +The 64 bit GUID of this dataset or bookmark, which does not change over its entire lifetime. +.sp +When a snapshot is sent to another pool, the received snapshot has the same GUID. Thus, \fBguid\fR is suitable to identify a snapshot across pools. +.RE + +.sp +.ne 2 +.na \fB\fBlogicalreferenced\fR\fR .ad .sp .6 |