QNAP TS-212 How to rebuild RAID manually from telnet

Scenario = replace a disk in QNAP TS-212 with RAID 1 configuration active

RAID rebuild should start automatically, but some times it could happen you got stuck with 1 Single Disk + 1 Mirroring Disk Volume:

According to the QNAP Support – How can I migrate from Single Disk to RAID 0/1 in TS-210/TS-212? , TS-210/TS-212 does not support Online RAID Level Migration. Therefore, please backup the data on the single disk to another location, install the second hard drive, and then recreate the new RAID 0/1 array (hard drive must be formatted).

The workaround is this:

1. Telnet to NAS as Admin
2. Check your current disk configuration for Disk #1 and Disk #2 =
   fdisk -l /dev/sda
   Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes
   255 heads, 63 sectors/track, 121601 cylinders
   Units = cylinders of 16065 * 512 = 8225280 bytesDevice Boot      Start         End      Blocks   Id  System
   /dev/sdb1               1          66      530125   83  Linux
   /dev/sdb2              67         132      530142   83  Linux
   /dev/sdb3             133      121538   975193693   83  Linux
   /dev/sdb4          121539      121600      498012   83  Linux

   fdisk -l /dev/sdb

   Disk /dev/sda: 1000.2 GB, 1000204886016 bytes
   255 heads, 63 sectors/track, 121601 cylinders
   Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
   /dev/sda1               1          66      530125   83  Linux
   /dev/sda2              67         132      530142   83  Linux
   /dev/sda3             133      121538   975193693   83  Linux
   /dev/sda4          121539      121600      498012   83  Linux

3. SDA is the first disk, SDB is the second disk
4. Verify the current status of RAID with this command =
   mdadm –detail /dev/md0
   /dev/md0:
   Version : 00.90.03
   Creation Time : Thu Sep 22 21:50:34 2011
   Raid Level : raid1
   Array Size : 486817600 (464.27 GiB 498.50 GB)
   Used Dev Size : 486817600 (464.27 GiB 498.50 GB)
   Raid Devices : 2
   Total Devices : 1
   Preferred Minor : 0
   Persistence : Superblock is persistentIntent Bitmap : Internal

   Update Time : Thu Jul 19 01:13:58 2012
   State : active, degraded
   Active Devices : 1
   Working Devices : 1
   Failed Devices : 0
   Spare Devices : 0

   UUID : 72cc06ac:570e3bf8:427adef1:e13f1b03
   Events : 0.1879365

   Number   Major   Minor   RaidDevice State
   0       0        0        0      removed
   1       8        3        1      active sync  /dev/sda3

5. As you can see the /dev/sda3 is working, so disk #1 is OK, but disk #2 is missing from RAID
6. Check if Disk #2 /dev/sdb is mounted (it should be) =
   mount/proc on /proc type proc (rw)
   none on /dev/pts type devpts (rw,gid=5,mode=620)
   sysfs on /sys type sysfs (rw)
   tmpfs on /tmp type tmpfs (rw,size=32M)
   none on /proc/bus/usb type usbfs (rw)
   /dev/sda4 on /mnt/ext type ext3 (rw)
   /dev/md9 on /mnt/HDA_ROOT type ext3 (rw)
   /dev/md0 on /share/MD0_DATA type ext4 (rw,usrjquota=aquota.user,jqfmt=vfsv0,user_xattr,data=ordered,delalloc,noacl)
   tmpfs on /var/syslog_maildir type tmpfs (rw,size=8M)
   /dev/sdt1 on /share/external/sdt1 type ufsd (rw,iocharset=utf8,dmask=0000,fmask=0111,force)
   tmpfs on /.eaccelerator.tmp type tmpfs (rw,size=32M)
   /dev/sdb3 on /share/HDB_DATA type ext3 (rw,usrjquota=aquota.user,jqfmt=vfsv0,user_xattr,data=ordered,noacl)
   
7. Dismount the /dev/sdb3 Disk #2 with this command =
   umount /dev/sdb3
8. Add Disk #2 into the RAID /dev/md0 =
   mdadm /dev/md0 –add /dev/sdb3
   mdadm: added /dev/sdb3
9. Check the RAID status and the rebuild should be started automatically =
   mdadm –detail /dev/md0
   /dev/md0:
   Version : 00.90.03
   Creation Time : Thu Sep 22 21:50:34 2011
   Raid Level : raid1
   Array Size : 486817600 (464.27 GiB 498.50 GB)
   Used Dev Size : 486817600 (464.27 GiB 498.50 GB)
   Raid Devices : 2
   Total Devices : 2
   Preferred Minor : 0
   Persistence : Superblock is persistentIntent Bitmap : Internal

   Update Time : Thu Jul 19 01:30:27 2012
   State : active, degraded, recovering
   Active Devices : 1
   Working Devices : 2
   Failed Devices : 0
   Spare Devices : 1

   Rebuild Status : 0% complete

   UUID : 72cc06ac:570e3bf8:427adef1:e13f1b03
   Events : 0.1879848

   Number   Major   Minor   RaidDevice State
          2       8       19        0      spare rebuilding   /dev/sdb3
          1       8        3        1      active sync   /dev/sda3

10. Check the NAS site for the rebuild % progress
11. After the RAID rebuild complete, restart NAS to clean all previous mount point folder for sdb3

Obtained from this link