appropriate location for hammer snapshots

[Matthew Dillon]

:OK I got it
:
:hammer config fs configfile

    Yes, also 'hammer viconfig <fs>'

:Sorry for asking in haste :-(
:Also please explain what rebalance, reblock and recopy are actually.
:And From my understanding pruning is when you remove meta data about
:transactions you are not interested in as configured by the 'prune'
:directive?
:
:Also how do we find out the optimum configurations for these
:parameters for our specific filesystem?
:is there any way to know if these operations are left uncompleted
:because of our configuration values?
:
:Thanks
:
:--Siju

    hammer cleanup is run automatically from cron by the system
    periodic scripts and its output should be in the daily root
    mail.

    The defaults will work for most filesystems.  If you have
    large drives (1TB+) you probably want to bump up the
    pruning and reblocking time to 10m or 15m and maybe run
    them twice a day 12h instead of 1d.

    snapshots 1d 60d	Make a daily snapshot (1d), keep 60-days
			worth of snapshots (60d).

    prune     1d 5m	Snapshots older than 60d (as specified above)
			will be deleted.  The filesystem will be
			pruned to remove deleted snapshots and any
			fine-grained junk between snapshots.

			This frees up some space over time but does
			not defragment the media.

			HAMMER will run the prune up to 5m as specified
			here and then stop, then pick up where it left
			off the next time.

    rebalance 1d 5m	This rebalances the on-media B-Tree.  This
			is typically a fast operation.

			HAMMER will run the rebalance up to 5m as specified
			here and then stop, then pick up where it left
			off the next time.

    reblock   1d 5m	This reblocks data and meta-data using a 95%
			fill level.  Basically what this does is try to
			repack any big blocks on the media which are
			partially empty in order to recover space.

			HAMMER will run the reblocking up to 5m as specified
			here and then stop, then pick up where it left
			off the next time.

    recopy    30d 10m	This reblocks data and meta-data using a 100%
			fill level.  Basically this reblocks everything
			in order to clean up any fragmentation which
			has occurred over time.

			As specified on this line HAMMER only spends
			10 minutes once every 30 days doing this.  However
			much it gets done it gets done.

					-Matt
					Matthew Dillon 
					<dillon at backplane.com>