I have the following RAID1 configuration: raiddev /dev/md0 raid-level 1 nr-raid-disks 2 nr-spare-disks 0 persistent-superblock 1 chunk-size 4 device /dev/hda1 raid-disk 0 device /dev/hdc1 raid-disk 1 The only one partition on my system is "root"-Partition. It's mounted on /dev/md0. Linux-Kernel: 2.4.18 Linux-Distribution: S.U.S.E 8 Prof. Everything works fine beside of error recovery of hda1: After hda1 has failed I tried to install a new disk instead of hda1 in the following way: 1. plug in a new disk on the place of hda1. 2. raidhotadd /dev/md0 /dev/hda1 3. install LILO After the data on /dev/hda1 was synced with the data on /dev/hdc1 the /proc/mdstat contained: Personalities : [raid1] read_ahead 1024 sectors md0 : active raid1 hda1[1] hdc1[0] 614784 blocks [2/2] [UU] unused devices: <none> !!! After system reboot, RAID didn't found hda1 !!! Here is the output of dmesg while rebooting: //////////////// DMESG OUTPUT BEGIN //////////////// md: md driver 0.90.0 MAX_MD_DEVS=256, MD_SB_DISKS=27 md: Autodetecting RAID arrays. [events: 00000015] md: autorun ... md: considering hdc1 ... md: adding hdc1 ... md: created md0 md: bind<hdc1,1> md: running: <hdc1> md: hdc1's event counter: 00000015 md0: former device hda1 is unavailable, removing from array! md: RAID level 1 does not need chunksize! Continuing anyway. request_module[md-personality-3]: Root fs not mounted md: personality 3 is not loaded! md :do_md_run() returned -22 md: md0 stopped. md: unbind<hdc1,0> md: export_rdev(hdc1) md: ... autorun DONE. .... md: raid1 personality registered as nr 3 md: Autodetecting RAID arrays. [events: 00000015] md: autorun ... md: considering hdc1 ... md: adding hdc1 ... md: created md0 md: bind<hdc1,1> md: running: <hdc1> md: hdc1's event counter: 00000015 md0: former device hda1 is unavailable, removing from array! md: RAID level 1 does not need chunksize! Continuing anyway. md0: max total readahead window set to 124k md0: 1 data-disks, max readahead per data-disk: 124k raid1: device hdc1 operational as mirror 0 raid1: md0, not all disks are operational -- trying to recover array raid1: raid set md0 active with 1 out of 2 mirrors md: updating md0 RAID superblock on device md: hdc1 [events: 00000016]<6>(write) hdc1's sb offset: 614784 md: recovery thread got woken up ... md0: no spare disk to reconstruct array! -- continuing in degraded mode md: recovery thread finished ... md: ... autorun DONE. md: swapper(pid 1) used obsolete MD ioctl, upgrade your software to use new ictls. reiserfs: checking transaction log (device 09:00) ... Using r5 hash to sort names ReiserFS version 3.6.25 VFS: Mounted root (reiserfs filesystem) readonly. change_root: old root has d_count=2 Trying to unmount old root ... okay Freeing unused kernel memory: 120k freed md: Autodetecting RAID arrays. md: autorun ... md: ... autorun DONE. //////////////// DMESG OUTPUT END //////////////// /proc/mdstat contained after reboot: Personalities : [raid1] read_ahead 1024 sectors md0 : active raid1 hdc1[0] 614784 blocks [2/1] [U_] unused devices: <none> My questions is: How do I recover the failed RAID1 disk (dev/hda1)? What I did wrong? ------------ Max Frolov. e-mail: wrungel@web.de ________________________________________________________________ Keine verlorenen Lotto-Quittungen, keine vergessenen Gewinne mehr! Beim WEB.DE Lottoservice: http://tippen2.web.de/?x=13 - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html