System: Settings: Tunables - change zfs transcation group defaults. (…

…timeout from 5 --> 90 seconds, dirty data sync percentage from 20 --> 5)

Usually firewalls are not processing a lot of disk write operations, in which case a forced every 5 second flush will lead to quite some wear on the underlying storage device (usually a solid state one these days).
Roughly 20GB per day is being written when using the upstream defaults and without much actual load. To compensate a bit for the reduction of forced syncs, we lower the threshold on the dirty data.

(cherry picked from commit d766ae2)
(cherry picked from commit b121118)

src/etc/inc/system.inc

@@ -122,6 +122,8 @@ function system_sysctl_defaults()
         'security.bsd.see_other_gids' => [ 'default' => '0' ],
         'security.bsd.see_other_uids' => [ 'default' => '0' ],
         'vfs.read_max' => [ 'default' => '32' ],
+        'vfs.zfs.dirty_data_sync_percent' => [ 'default' => '5', 'required' => true ],
+        'vfs.zfs.txg.timeout' => [ 'default' => '90', 'required' => true ],
         'vm.pmap.pti' => [ 'default' => '1' ],
     ];
 }