Sending a ZFS Snapshot

You can use the zfs send command to send a copy of a snapshot and receive the snapshot in another pool on the same system or in another pool on a different system that is used to store backup data. For example, to send the snapshot on a different pool on the same system, use syntax similar to the following:

# zfs send tank/data@snap1 | zfs recv spool/ds01

You can use zfs recv as an alias for the zfs receive command.

If you are sending the snapshot stream to a different system, pipe the zfs send output through the ssh command. For example:

host1# zfs send tank/dana@snap1 | ssh host2 zfs recv newtank/dana

When sending a full stream, the destination file system must not exist.

You can send incremental data by using the zfs send -i option. For example:

host1# zfs send -i tank/dana@snap1 tank/dana@snap2 | ssh host2 zfs recv newtank/dana

Note that the first argument is the earlier snapshot (snap1) and the second argument (snap2) is the later snapshot. In this case, the newtank/dana file system must exist for the incremental receive to be successful.

The incremental snap1 source can be specified as the last component of the snapshot name. This shortcut means you only have to specify the name after the @ sign for snap1, which is assumed to be from the same file system as snap2. For example:

host1# zfs send -i snap1 tank/dana@snap2 > ssh host2 zfs recv newtank/dana

This syntax is equivalent to the above example of the incremental syntax.

The following message is displayed if you attempt to generate an incremental stream from a different file system snapshot1:

cannot send 'pool/fs@name': not an earlier snapshot from the same fs

If you need to store many copies, you might consider compressing a ZFS snapshot stream representation with the gzip command. For example:

# zfs send pool/fs@snap | gzip > backupfile.gz