Hi, Did the following. 1. Shutdown the server and replaced /dev/sdb with a new blank hard drive. 2. Power up the server and I am getting the following error and does not boot up. mount: you must specify the filesystem type kernel panic - not syncing attempted to kill init 3. Shutdown the server and put back the old hard drive and all is ok. What did I miss out? Need advice on how to solve this. Here are some details about the server. Grub. --------- start -------------------- default=0 timeout=5 splashimage=(hd0,0)/grub/splash.xpm.gz hiddenmenu serial --unit=0 terminal serial title CentOS (2.6.32-279.19.1.el6.x86_64) root (hd0,0) kernel /vmlinuz-2.6.32-279.19.1.el6.x86_64 ro root=/dev/md1 rd_NO_LUKS rd_NO_LVM rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYBOARDTYPE=pc KEYTABLE=us crashkernel=auto rhgb quiet console=ttyS0 initrd /initramfs-2.6.32-279.19.1.el6.x86_64.img title CentOS (2.6.32-279.11.1.el6.x86_64) root (hd0,0) kernel /vmlinuz-2.6.32-279.11.1.el6.x86_64 ro root=/dev/md1 rd_NO_LUKS rd_NO_LVM rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYBOARDTYPE=pc KEYTABLE=us crashkernel=auto rhgb quiet console=ttyS0 initrd /initramfs-2.6.32-279.11.1.el6.x86_64.img ----------- end -------------------- Check if the grub is in both drives. ------------ start ---------------- [root ~]# dd bs=512 count=1 if=/dev/sda 2>/dev/null | strings ZRrI D|f1 GRUB Geom Hard Disk Read Error [root ~]# dd bs=512 count=1 if=/dev/sdb 2>/dev/null | strings ZRrI D|f1 GRUB Geom Hard Disk Read Error ------------- end ----------------- mdstat. ---------- start ------------------ [root ~]# cat /proc/mdstat Personalities : [raid1] md1 : active raid1 sda3[0] sdb3[2] 972646232 blocks super 1.2 [2/2] [UU] md0 : active raid1 sda1[0] sdb1[1] 104320 blocks [2/2] [UU] unused devices: <none> ----------- end ------------------- mdadm. ------------ start --------------------- [root ~]# mdadm --examine --scan ARRAY /dev/md0 UUID=353b8766:d1f48983:6b357bf1:4e91e489 ARRAY /dev/md/1 metadata=1.2 UUID=a4c3c6cb:0f1a7b1e:e1b463da:06d1cd0d name=hostname.domain.com.sg:1 -------------- end --------------------- fstab. ------------- start ------------------- /dev/md1 / ext4 defaults,usrjquota=aquota.user,grpjquota=aquota.group,jqfmt=vfsv0 1 1 /dev/md0 /boot ext3 defaults 1 2 /dev/sda2 swap swap defaults 0 0 /dev/sdb2 swap swap defaults 0 0 tmpfs /dev/shm tmpfs defaults 0 0 devpts /dev/pts devpts gid=5,mode=620 0 0 sysfs /sys sysfs defaults 0 0 proc /proc proc defaults 0 0 -------------- end -------------------- fdisk. ------------- start --------------------- [root ~]# fdisk -l Disk /dev/sda: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Device Boot Start End Blocks Id System /dev/sda1 1 13 104391 fd Linux raid autodetect /dev/sda2 14 512 4008217+ 82 Linux swap / Solaris /dev/sda3 513 121601 972647392+ fd Linux raid autodetect Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Device Boot Start End Blocks Id System /dev/sdb1 1 13 104391 fd Linux raid autodetect /dev/sdb2 14 512 4008217+ 82 Linux swap / Solaris /dev/sdb3 513 121601 972647392+ fd Linux raid autodetect Disk /dev/md0: 106 MB, 106823680 bytes 2 heads, 4 sectors/track, 26080 cylinders Units = cylinders of 8 * 512 = 4096 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/md1: 996.0 GB, 995989741568 bytes 2 heads, 4 sectors/track, 243161558 cylinders Units = cylinders of 8 * 512 = 4096 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 --------------- end ---------------------- df -h ------------ start ---------------------- [root ~]# df -h Filesystem Size Used Avail Use% Mounted on /dev/md1 914G 148G 719G 18% / tmpfs 7.8G 0 7.8G 0% /dev/shm /dev/md0 99M 64M 31M 68% /boot -------------- end ---------------------- uname -r ----------- start ------------------ [root ~]# uname -r 2.6.32-279.19.1.el6.x86_64 Using CentOS 6 64bit. ------------- end ------------------
Just found out the UUID do not match also. Could this be the problem? ---------- start ------------------ [root ~]$ blkid /dev/sda1: LABEL="/boot" UUID="7c7009d3-9e60-4b3c-8c1b-90d33d54d97f" TYPE="ext3" /dev/sda2: LABEL="SWAP-sda2" UUID="a0cc1000-9783-4926-9202-843463a06fbe" TYPE="swap" /dev/sda3: LABEL="/" UUID="b3d2736e-5048-409e-bffa-f52a9af089fc" TYPE="ext3" ----------- end ------------------- ---------- start --------------------- [root ~]$ ls -l /dev/disk/by-uuid/ total 0 lrwxrwxrwx 1 root root 9 Sep 6 03:18 85a5e188-cbfd-4376-8531-f8c598e876c8 -> ../../md1 lrwxrwxrwx 1 root root 10 Sep 6 03:16 86f84624-b3e7-4a01-bac2-95e70aa3d513 -> ../../sda2 lrwxrwxrwx 1 root root 9 Sep 6 03:18 e00f19e1-15b5-4f3e-bba1-3320b3c3d19c -> ../../md0 ---------- end ----------------------- --------- start --------------- [root ~]# mdadm --examine --scan ARRAY /dev/md0 UUID=353b8766:d1f48983:6b357bf1:4e91e489 ARRAY /dev/md/1 metadata=1.2 UUID=a4c3c6cb:0f1a7b1e:e1b463da:06d1cd0d name=hostname.domain.com.sg:1 ---------- end ----------------
While investigating, just found out the UUID do not match also. Could this be the problem that the raid could not boot up without one drive? ---------- start ------------------ [root ~]$ blkid /dev/sda1: LABEL="/boot" UUID="7c7009d3-9e60-4b3c-8c1b-90d33d54d97f" TYPE="ext3" /dev/sda2: LABEL="SWAP-sda2" UUID="a0cc1000-9783-4926-9202-843463a06fbe" TYPE="swap" /dev/sda3: LABEL="/" UUID="b3d2736e-5048-409e-bffa-f52a9af089fc" TYPE="ext3" ----------- end ------------------- ---------- start --------------------- [root ~]$ ls -l /dev/disk/by-uuid/ total 0 lrwxrwxrwx 1 root root 9 Sep 6 03:18 85a5e188-cbfd-4376-8531-f8c598e876c8 -> ../../md1 lrwxrwxrwx 1 root root 10 Sep 6 03:16 86f84624-b3e7-4a01-bac2-95e70aa3d513 -> ../../sda2 lrwxrwxrwx 1 root root 9 Sep 6 03:18 e00f19e1-15b5-4f3e-bba1-3320b3c3d19c -> ../../md0 ---------- end ----------------------- --------- start --------------- [root ~]# mdadm --examine --scan ARRAY /dev/md0 UUID=353b8766:d1f48983:6b357bf1:4e91e489 ARRAY /dev/md/1 metadata=1.2 UUID=a4c3c6cb:0f1a7b1e:e1b463da:06d1cd0d name=hostname.domain.com.sg:1 ---------- end ----------------
For sake of completeness, and preventing others from using OP's wrong commands. I assume OP used bs=512 for copying the MBR Code: dd bs=512 count=1 if=/dev/sda 2>/dev/null | strings no wonder it doesn't work the mbr is only 446 bytes long followed by 64 bytes partition table and 2 bytes signature. the correct way to prepare a new bootable raid1 disk 1. first to make sure your partitiontables are identical. 2. enable boot flag with fdisk cfdisk or whatever 3. use : Code: dpkg-reconfige grub-pc and select all raw hd's ( not the mdadm ones ) 4. update initramfs
