Neil, What seems desirable to me is a way to take a new (larger) spare drive and add it to a RAID1 for a particular RAID 4/5/6 component, and then when it's sync'd, replace the now redundant small drive with another larger drive. Wash, rinse, repeat. This way the array is never degraded. Though I imagine that this particular arrangement doesn't have the benefit of the stripe rewrite when encountering a latent error on the drive that is being migrated. [Presumably the failing addresses could be cycled through the check from userland though, by doing a read above the stacked RAID.] One could start a RAID 4/5/6 array over a degraded RAID1 for each component, (i.e., a degraded RAID1). I haven't been following the metadata changes closely. Is it possible to do this with external MD metadata? It can also be done with device-mapper, but dm-mirror is very immature compared to MD RAID1. Comments? Regards, Bill Rugolsky - 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
