Way to prune/limit the ZFS zpool history?

[Dan Nelson]

In the last episode (Jan 20), Geoff Fritz said:
> I've been experimenting with a series scripts that takes ZFS
> snapshots every minute, eventually destroying the oldest so that only
> so many remain available for a given window of time.
> 
> This may seem a trivial concern with hard drive sizes being what they
> are these days, but after running a "zpool history" I started
> thinking that a ZFS create and destroy being performed every minute
> would add up to a lot over the course of a few years (current
> estimate is 62MB/year for the naming scheme of my snapshots).

According to
http://docs.sun.com/app/docs/doc/819-5461/gdswe?l=en&a=view , the zpool
history file is between 128K and 32MB, depending on the size of the
pool.  The FreeBSD import at
/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_history.c agrees
with the docs :)

-- 
	Dan Nelson
	dnelson at allantgroup.com