On Wed, 08 Sep 2010 03:58:52 +0000 "Michael Sallaway" <michael@xxxxxxxxxxxx> wrote: > > From: Neil Brown <neilb@xxxxxxx> > > Subject: Re: 3-way mirrors > > Sent: 07 Sep '10 22:01 > > > > This is already possible via the sync_min and sync_max sysfs files. > > Write a number of sectors to sync_max and a lower number to sync_min. > > Then write 'repair' to 'sync_action'. > > When sync_completed reaches sync_max, the repair will pause. > > You can then let it continue by writing a larger number to sync_max, or tell > > it to finish by writing 'idle' to 'sync_action'. > > Interesting... will this also work for a rebuild/recovery? If so, how do I start a rebuild from a particular location? (do I just write the sync_min sector before adding the replacement drive to the array, and it will start from there when I add it?) Why would you want to? sync_min is only honoured when you request a check/repair operation. When md determines a resync or recovery is needed, it starts the where it needs to start from, which is normally the beginning. You can add a new device entirely by writing to sysfs files. In this case you can set the 'recovery_start' for that device. This tells md that it has already recovered some of the array. > > Are all sector counts in terms of a drive sector position, or an array sector position? For raid10, the sector counts are array sector position. For raid5/raid6, the sector counts are drive sector position with data_offset subtracted (so they start from 0). For raid1, both of the above descriptions produce the same answer, so both are valid descriptions. NeilBrown > > Thanks, > Michael > -- > 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
