Add a periodic zfs scrub script.

Features:
 - configurable amount of days between scrubs (default value or per pool)
 - do not scrub directly after pool creation (respects the configured
   number of days between scrubs)
 - do not scrub if a scrub is in progress
 - tells how to see the status of the scrub
 - tells how many days since the last scrub if it skips the scrubbing
 - warns if a non-existent pool is specified explicitely
   (default: no pools specified -> all currently imported pools are
   handled)
 - runs late in the periodic run to not slow down the other periodic daily
   scripts

Discussed on:	fs@

1 files changed, 20 insertions, 1 deletions

diff --git a/share/man/man5/periodic.conf.5 b/share/man/man5/periodic.conf.5
index 2052a1b..7947a59 100644
--- a/share/man/man5/periodic.conf.5
+++ b/share/man/man5/periodic.conf.5
@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd May 12, 2007
+.Dd June 15, 2010
 .Dt PERIODIC.CONF 5
 .Os
 .Sh NAME
@@ -611,6 +611,25 @@ when
 .Va daily_queuerun_enable
 is set to
 .Dq Li YES .
+.It Va daily_scrub_zfs_enable
+.Pq Vt bool
+Set to
+.Dq Li YES
+if you want to run a zfs scrub periodically.
+.It Va daily_scrub_zfs_pools
+.Pq Vt str
+A space separated list of names of zfs pools to scrub.
+If the list is empty or not set, all zfs pools are scrubbed.
+.It Va daily_scrub_zfs_default_threshold
+.Pq Vt int
+Number of days between a scrub if no pool-specific threshold is set.
+The default value if no value is set is 30.
+.It Va daily_scrub_zfs_ Ns Ao Ar poolname Ac Ns Va _threshold
+.Pq Vt int
+The same as
+.Va daily_scrub_zfs_default_threshold
+but specific to the pool
+.Va Ns Ao Ar poolname Ac Ns .
 .It Va daily_local
 .Pq Vt str
 Set to a list of extra scripts that should be run after all other