No, you do not have to run 'hammer now' to create a snapshot.  The

    kernel syncs all filesystems every 30 seconds, so if you do nothing

    at all you get a snapshot granularity of 30 seconds.
    Where you would use 'hammer now' is if you wanted the most current

    snapshot possible for the purpose of, say, backing up your filesystem

    to another machine.  You might do something like this:
	set timestamp = `hammer now`

	cpdup /mountpoint/@@$timestamp targethost:/somepath
    But if you didn't care about that you could just go back far enough

    that you get a stable historical view... e.g. go back 1 minute and you

    would have a stable view into your filesystem.
	set timestamp = `hammer stamp 60s`		<------ doesn't sync

	cpdup /mountpoint/@@$timestamp targethost:/somepath
    Ultimately the idea of managing filesystems this way is to still do

    regular backups from your production machine to your backup machine

    (ultimately by way of replication), with both running HAMMER, but only

    retain a limited amount of history on the production box.  You might

    desire to retain only one week's worth of history on the production box,

    retain one month's history on your local backup box, and retain a very

    granular one year's worth of history on your remote backup box.
    Come to think of it, I should add some more directives to the

    'hammer prune' command to make that easier to specify.
    Until I implement a live replication 'feed' the minimum granularity on

    the backup box will be how often you do your backups (e.g. once a day),

    and you can prune it into more granular forms from that starting point.

    Once we have a live replication feed the backup box will have the same

    30-second granularity that the production machine has.
    A major bullet point for this style of management is that the retention

    policy on the various boxes can be different even though they are

    all slaved off the same production filesystem.
		...
[ message continues ]