Explanation: https://library.netapp.com/ecmdocs/ECMP1196979/html/man1/na_snapmirror.1.html
http://www.uow.edu.au/~blane/netapp/ontap/cmdref/man1/na_options.1.htm
update [ -S source ] [ -k kilobytes ] [ -s src_snap ] [ -c create_dest_snap ] [ -w ] destination
For asynchronous mirrors, an update is immediately started from the source to the destination to update the mirror with the contents of the source.
For synchronous mirrors, a snapshot is created on the source volume which becomes visible to clients of the destination volume.
The update command must be issued on the destination node.status [ -l | -t | -q ] [ volume | qtree ... ]
Reports status of all the SnapMirror relationships with a source and/or destination on this node. This command also reports whether SnapMirror is on or off. If any volume or qtree arguments are given to the command, only the SnapMirror relationships with a matching source or destination will be reported. If the argument is invalid, there won't be any status in the output.initialize [ -S source ] [ -k kilobytes ] [ -s src_snap ] [ -c create_dest_snap ]
[ -w ] destination Starts an initial transfer over the network. An initial transfer is required before update transfers can take place.
The initialize command must be issued on the destination node. If the destination is a volume, it must be restricted (see na_vol(1) for information on how to examine and restrict volumes). If the destination is a qtree, it must not already exist (see na_qtree(1) for information on how to list qtrees). If a qtree already exists, it must be renamed or removed (using an NFS or CIFS client), or snapmirror initialize to that qtree will not work.snapmirror.access
This option determines which SnapMirror destination filers may initiate transfers, and over which network interfaces. When set to "legacy", SnapMirror uses the older snapmirror.allow to determine access. The option value is a string containing an expression which provides the access filter. An example of the options command for snapmirror.access is options snapmirror.access host=toaster,fridge. The default value is "legacy". See na_snapmirror(1) , na_snapmirror.allow(5) and na_protocolaccess(8) for more details.
The snapmirror.allow file exists on the source filer used for SnapMirror.