On Mon, 10 May 2010 15:49:20 -0700 Daniel Boggs <BecauseImAwesome@xxxxxxxx> wrote: > Question: > > If I use: > > >>> echo repair > /sys/block/mdX/md/sync_action > > to start a check action, then stop it with > > >>> echo idle > /sys/block/mdX/md/sync_action > > and later start it up again. Will it start again from the > "beginning", or is it able to pick up where it left off? Yes .. if you have a recent enough kernel. When you write 'idle' you should find the current sector stored in 'sync_min'. When you write 'repair' again it will start from the value in 'sync_min'. Obviously if you stop and restart the array you will loose this value unless you store it in a file somewhere and recover it. > > Essentially if I find the repair/sync action causes too much of a > performance hit, could I have it run only during hours that I know the > array will not be in use and still have the array checked in its > entirety, or is the only way to accomplish that to let the action run > from start to finish? You can also reduce the impact by slowing down the scan using sync_speed_min and sync_speed_max. 'min' is an upper limit to the speed when other IO is happening, and 'max' is an upper limit when there is no other IO. NeilBrown > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
