Hello, I have a working RAID1 with 2 large SATA drives and I`m using AHCI on ICH6 chipset. Three days ago, one drive just mysteriously failed Oct 19 22:45:37 xaser kernel: ata1: error occurred, port reset Oct 19 22:48:09 xaser kernel: ata2: status=0x01 { Error } Oct 19 22:48:09 xaser kernel: ata2: error=0x40 { UncorrectableError } Oct 19 22:48:09 xaser kernel: ata1: error occurred, port reset Oct 19 22:48:09 xaser kernel: ata2: status=0x01 { Error } Oct 19 22:48:09 xaser kernel: ata2: error=0x40 { UncorrectableError } Oct 19 22:48:09 xaser kernel: SCSI error : <1 0 0 0> return code = 0x8000002 Oct 19 22:48:09 xaser kernel: sdb: Current: sense key: Medium Error Oct 19 22:48:09 xaser kernel: Additional sense: Unrecovered read error - aut o reallocate failed Oct 19 22:48:09 xaser kernel: end_request: I/O error, dev sdb, sector 440990889 Oct 19 22:48:09 xaser kernel: raid1: Disk failure on sdb9, disabling device. The drive appeared dead to all my attempts to get it to work without power cycle. Today, the replacement drive was shipped, so I powercycled the machine and *wonder wonder* the drive was back. So I `badblocks` and resynced again and its working perfect. I know I can use the "new" drive I bought today as spare, but I really miss the point of a spare for raid1. I think, it makes much more sense, to build in the drive as a live one, so instead of RAID1 made of 2 drives, I`ll get RAID1 made of 3 drives. I use mdadm to manage the drives. If I use --manage --add and add the drive(partition) to the array, it becomes a spare disk and this is not what I want it to do. Is there a way to upgrade my raid, without destroying data? cheers, juraj - 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