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rb:linuxreplacemdmirror [17/12/2012 21:43]
andrew [Current md partitions]
rb:linuxreplacemdmirror [10/10/2013 15:21]
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-====== Replace md mirror device ====== 
  
- 
-====== Background ====== 
- 
-System is Centos 5.6. \\ 
-Warning in logwatch:- \\ 
- 
-  ​ 
-  --------------------- Smartd Begin ------------------------ ​ 
-  ​ 
-    
-  Currently unreadable (pending) sectors detected: 
-  /dev/sda - 96 Time(s) 
-  53 unreadable sectors detected 
-    
-  Offline uncorrectable sectors detected: 
-  /dev/sda - 96 Time(s) 
-  53 offline uncorrectable sectors detected 
-    
-  ---------------------- Smartd End ------------------------- ​ 
- 
- 
-Boot device is /dev/sda, /dev/sdb did not have correct boot sector. 
- 
- 
-===== Fix non bootable /dev/sdb ===== 
- 
- 
-Make /dev/sdb bootable:- \\ 
- 
- 
-  [optimax]# grub 
-  ​ 
-  GNU GRUB version 0.95 (640K lower / 3072K upper memory) 
-  ​ 
-  [ Minimal BASH-like line editing is supported. For the first word, TAB 
-  lists possible command completions. Anywhere else TAB lists the possible 
-  completions of a device/​filename.] 
-  ​ 
-  grub> root (hd0,0) 
-  Filesystem type is ext2fs, partition type 0xfd 
-  ​ 
-  grub> setup (hd0) 
-  Checking if "/​boot/​grub/​stage1"​ exists... yes 
-  Checking if "/​boot/​grub/​stage2"​ exists... yes 
-  Checking if "/​boot/​grub/​e2fs_stage1_5"​ exists... yes 
-  Running "embed /​boot/​grub/​e2fs_stage1_5 (hd0)"​... 15 sectors are embedded. 
-  succeeded 
-  Running "​install /​boot/​grub/​stage1 (hd0) (hd0)1+15 p (hd0,​0)/​boot/​grub/​stage2 
-  /​boot/​grub/​grub.conf"​... succeeded 
-  Done. 
-  ​ 
-  grub> root (hd1,0) 
-  Filesystem type is ext2fs, partition type 0xfd 
-  ​ 
-  grub> setup (hd1) 
-  Checking if "/​boot/​grub/​stage1"​ exists... yes 
-  Checking if "/​boot/​grub/​stage2"​ exists... yes 
-  Checking if "/​boot/​grub/​e2fs_stage1_5"​ exists... yes 
-  Running "embed /​boot/​grub/​e2fs_stage1_5 (hd1)"​... 15 sectors are embedded. 
-  succeeded 
-  Running "​install /​boot/​grub/​stage1 (hd1) (hd1)1+15 p (hd1,​0)/​boot/​grub/​stage2 
-  /​boot/​grub/​grub.conf"​... succeeded 
-  Done. 
-  ​ 
-  grub> quit 
- 
- 
- 
- 
-===== Current md partitions ===== 
- 
- 
-  [root@optiplex ~]# df -h 
-  Filesystem ​           Size  Used Avail Use% Mounted on 
-  /​dev/​md1 ​              ​19G ​ 4.1G   ​14G ​ 23% / 
-  /​dev/​md3 ​             303G  236G   ​53G ​ 82% /data 
-  /​dev/​md2 ​             1.9G  827M 1011M  45% /var 
-  /​dev/​md0 ​              ​99M ​  ​37M ​  ​58M ​ 39% /boot 
- 
- 
- 
-===== Remove failed partitions from md arrays ===== 
- 
-Fail partitons:- \\ 
- 
-  # mdadm --manage /dev/md0 --fail /dev/sda1 
-  # mdadm --manage /dev/md1 --fail /dev/sda2 
-  ​ 
-Remove from md arrays:​-\\  ​ 
-  ​ 
-  # mdadm --manage /dev/md0 --remove /dev/sdb1 
-  # mdadm --manage /dev/md1 --remove /dev/sdb2 
-  ​ 
-Shutdown system and replace faulty disk. If your disks are hot swap, this step may not be needed.\\ 
-  ​ 
-    # shutdown -h now 
- 
-Swap over faulty disk for new disk.\\ 
- 
-Copy partiton table from existing good disk to new disk, double check you are copying the right partition table to the right disk. Then check again :-} 
- 
-  # sfdisk -d /dev/sdb | sfdisk /dev/sda 
-  ​ 
- 
-Add partitons back in to md array:- \\ 
- 
-  # mdadm --manage /dev/md0 --add /dev/sda1 
-  mdadm: added /dev/sda1 
-  # mdadm --manage /dev/md1 --add /dev/sda2 
-  mdadm: added /dev/sda2 
- 
- 
-Watch the resync progress with:-\\ 
- 
-  # cat /​proc/​mdstat 
- 
- 
- 
- 
-Install grub loader back on to new disk. 
- 
-  grub> find /​grub/​stage1 
-  (hd0,0) 
-  (hd1,0) 
-  ​ 
-  grub> device (hd0) /dev/sdb (or /dev/hdb for IDE drives) 
-  grub> root (hd0,0) 
-  grub> setup (hd0) 
-  grub>​quit 
- 
- 
-  

rb/linuxreplacemdmirror.txt ยท Last modified: 10/10/2013 15:21 (external edit)