1. Note: This guide apply to all TS/SS series NAS except TS-401T, TS-411U
QNAP NAS Data Recovery
Charley, Yufan, Alan
Note: This guide apply to all TS/SS series NAS except TS-401T, TS-411U

2. Agenda How does the QNAP NAS RAID work?
NAS is OK but cannot access data
raidtab is broken or missing
Check raid settings and configure right raidtab
HDD have no partitions
Use parted to recreate the partitions
Partitions have no MD superblock
mdadm -CfR --assume-clean
RAID array can't be assembled or status is inactive
check above and make sure every disks on raid exist
RAID array can't been mounted
e2fsck, e2fsck -b
Able to mount RAID but data is disappear
umount and e2fsck, if not work, try data recovery
RAID is in degraded, read-only
backup the data then mdadm -CfR, it not work, recreate the RAID
NAS fail
Mount HDD(s) with another QNAP NAS (System Migration)
Mount HDD(s) with PC ( R-Studio/ ext3/4 reader) (3rd party tool )
Data are deleted by user/administrator accidentally 
 data recovery company, photorec, r-studio/r-linux

3. How does the QNAP NAS RAID work
Please check the following link for complete tutorial
          
Above guide include all the procedures on our NAS to create a RAID volume.  
Pre-requirement: download losetup utility to a NAS.
      
      
After download, use tar -xf to extract and run it. This utility is used to create virtual disk for simulating the disks on above tutorial. 

4. Introduction of mdadm command
#mdadm -E /dev/sda3 > that will tell if it is md disk 
#mdadm -Af /dev/md0 /dev/sd[a-d]3 > that will get available md disk into raid array   
#mdadm -CfR -l5 -n8 --assume-clean /dev/md0 /dev/sd[a-h]3 > that will overwrite the mdstat on each disk
> -CfR force to create the raid array   
> -l5 = raid 5array
> -n8 = available md disk
> --assume-clean  without data partition syncing

5. Introduction of two scripts
 # config_util Usage: config_util input     input=0: Check if any HD existed.     input=1: Mirror ROOT partition.     input=2: Mirror Swap Space (not yet).     input=4: Mirror RFS_EXT partition.
>> usually we have config_util 1 to get the md9 ready 
 # storage_boot_init Usage: storage_boot_init phase         phase=1: mount ROOT partition.         phase=2: mount DATA partition, create storage.conf and refresh disk.         phase=3: Create_Disk_Storage_Conf.
>> usually we have storage_boot_init 1 to mount the md9

6. RAID Issue - raidtab is broken
raidtab is used to check if the disk is in RAID group or single and show the RAID information on web UI.
If the disk is in RAID but Web UI show it is single, or the RAID information is different to the actual disk RAID data ( checked by mdadm -E), then the raidtab should be corrupt. Then you need to manually edit the raidtab file to comply the actual RAID status. 
Check the following slides for raidtab contents

7. RAID Issue - raidtab is broken
Single
No raidtab
RAID 0 Stripping
raiddev /dev/md0
        raid-level      0
        nr-raid-disks   2
        nr-spare-disks  0
        chunk-size      4
        persistent-superblock   1
        device  /dev/sda3
        raid-disk       0
        device  /dev/sdb3
        raid-disk       1

8. raidtab for RAID-1 and JBOD
RAID-1 Mirror
raiddev /dev/md0
        raid-level      1
        nr-raid-disks   2
        nr-spare-disks  0
        chunk-size      4
        persistent-superblock   1
        device  /dev/sda3
        raid-disk       0
        device  /dev/sdb3
        raid-disk       1
JBOD Linear
raiddev /dev/md0
        raid-level      linear
        nr-raid-disks   3
        nr-spare-disks  0
        chunk-size      4
        persistent-superblock   1
        device  /dev/sda3
        raid-disk       0
        device  /dev/sdb3
        raid-disk       1
        device  /dev/sdc3
        raid-disk       2

9. raidtab for RAID-5 and RAID-5+hot spare
raiddev /dev/md0
        raid-level      5
        nr-raid-disks   3
        nr-spare-disks  0
        chunk-size      4
        persistent-superblock   1
        device  /dev/sda3
        raid-disk       0
        device  /dev/sdb3
        raid-disk       1
        device  /dev/sdc3
        raid-disk       2
RAID-5 + Hot spare
raiddev /dev/md0
        raid-level      5
        nr-raid-disks   3
        nr-spare-disks  1
        chunk-size      4
        persistent-superblock   1
        device  /dev/sda3
        raid-disk       0
        device  /dev/sdb3
        raid-disk       1
        device  /dev/sdc3
        raid-disk       2
        device  /dev/sdd3
        spare-disk      0

10. raidtab for RAID-5 +global spare and RAID-6
raidtab is same as RAID-5
On uLinux.conf, add a line if global spare disk is disk 4:
[Storage] 
GLOBAL_SPARE_DRIVE_4 = TRUE
RAID-6
raiddev /dev/md0
        raid-level      6
        nr-raid-disks   4
        nr-spare-disks  0
        chunk-size      4
        persistent-superblock   1
        device  /dev/sda3
        raid-disk       0
        device  /dev/sdb3
        raid-disk       1
        device  /dev/sdc3
        raid-disk       2
        device  /dev/sdd3
        raid-disk       3

11. raidtab for RAID-10 RAID-10 raiddev /dev/md0 raid-level 10
        nr-raid-disks   4
        nr-spare-disks  0
        chunk-size      4
        persistent-superblock   1
        device  /dev/sda3
        raid-disk       0
        device  /dev/sdb3
        raid-disk       1
        device  /dev/sdc3
        raid-disk       2
        device  /dev/sdd3
        raid-disk       3

12. Raid fail - HDDs have no partitions
When use the following commands to check the HDD, there is no partition or only one partition. 
# parted /dev/sdx print
The following is sample.
# blkid    ** this command show all partitions on the NAS
Note: fdisk -l cannot show correct partition table for 3TB HDDs

13. RAID fail - HDDs have no partitions (cont.)
The following tool (x86 only) can help us to calculate correct partition size according to the HDD size. Please save it in your NAS (x86 model) and make sure the file size is 10,086 bytes. 
1. Get every disk size.
# cat /sys/block/sda/size
2. Get the disk partition list. It should contain 4 partitions if normal.
# parted /dev/sda print
Model: Seagate ST AS (scsi)
Disk /dev/sda: 320GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Number  Start   End     Size   Type     File system     Flags
 1      32.3kB  543MB   543MB  primary  ext3            boot
 2      543MB   1086MB  543MB  primary  linux-swap(v1)
 3      1086MB  320GB   318GB  primary  ext3
 4      320GB   320GB   510MB  primary  ext3

14. RAID fail - HDDs have no partitions (cont.)
3. Run the tool in your NAS to get the recover commands.
# Create_Partitions /dev/sda
/dev/sda size
disk_size=
/usr/sbin/parted /dev/sda -s mkpart primary 40s s
/usr/sbin/parted /dev/sda -s mkpart primary s s
/usr/sbin/parted /dev/sda -s mkpart primary s s
/usr/sbin/parted /dev/sda -s mkpart primary s s
If the disk contains none partition, run the 4 commands.
If the disk contains only 1 partition, run the last 3 commands.
If the disk contains only 2 partition, run the last 2 commands.
If the disk contains only 3 partition, run the last 1 commands.
4. Run above partitions commands depends on existing partition number. 
5. Check the disk partition after recover. And it should contain 4 partitions now. 
# parted /dev/sda print
Model: Seagate ST AS (scsi)
Disk /dev/sda: 320GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Number  Start   End     Size   Type     File system     Flags
 1      32.3kB  543MB   543MB  primary  ext3            boot
 2      543MB   1086MB  543MB  primary  linux-swap(v1)
 3      1086MB  320GB   318GB  primary  ext3
 4      320GB   320GB   510MB  primary  ext3
6.  Please then run "sync" or reboot the NAS for the new partition to take effect. 

15. RAID fail - Partitions have no md superblock
If one or all HDD partitions are lost, or the partitions have no md superblock for unknown reason, use the mdadm -CfR command to recreate the RAID.  
        # mdadm -CfR --assume-clean /dev/md0 -l 5 -n 4 /dev/sda3...
Note: 
Make sure the disk is in correct sequence.  Use "mdadm -E" or check raidtab to confirm
If one of the disk is missing or have problem, replace the disk with "missing".  For example: 
# mdadm -CfR --assume-clean /dev/md0 -l 5 -n 4 /dev/sda3 missing /dev/sdc3 /dev/sdd3

16. RAID fail - RAID can't be assembled or status is inactive
Check partitions, md superblock status
Check if there is any RAID disk missing / faulty
 Use "mdadm -CfR --assume-clean" to recreate the RAID

17. no md0 for array , manually create the md0 with mdadm -CfR

18. RAID fail - Cann't be mounted, status unmount
1. Make sure the raid status is active (more /proc/mdstat)
2. try manually mount
    # mount /dev/md0 /share/MD0_DATA -t ext3
    # mount /dev/md0 /share/MD0_DATA -t ext4
    # mount /dev/md0 /share/MD0_DATA -o ro (read only)
3. use e2fsck / e2fsck_64 to check 
    # e2fsck -ay /dev/md0 (auto and continue with yes)
4. If there are many errors when check, memory may not enough, need to create more swap space as the procedure on next slide.

19. RAID fail - Cann't be mount, status unmount (cont.)
Use the following command to create more swap space
[~] # more /proc/mdstat
md8 : active raid1 sdh2[2](S) sdg2[3](S) sdf2[4](S) sde2[5](S) sdd2[6](S) sdc2[7](S) sdb2[1] sda2[0]
      blocks [2/2] [UU]
[~] # swapoff /dev/md8
[~] # mdadm -S /dev/md8
mdadm: stopped /dev/md8
[~] # mkswap /dev/sda2
Setting up swapspace version 1, size = kB
no label, UUID=7194e0a9-be7a-43ac-829f-fd2d55e07d62
[~] # mkswap /dev/sdb2
no label, UUID=0af8fcdd-8ed1-4fca-8f d86f9474
[~] # mkswap /dev/sdc2
no label, UUID=f40bd c71-b8ff-9c1e9fbff6bf
[~] # mkswap /dev/sdd2
no label, UUID=4dad1835-8d88-4cf1-a851-d80a87706fea
[~] # swapon /dev/sda2
[~] # swapon /dev/sdb2
[~] # swapon /dev/sdc2
[~] # swapon /dev/sdd2
[~] # e2fsck_64 -fy /dev/md0

20. RAID fail - Cann't be mount, status unmount (cont.)
If there is no file system superblock or the check fail, you can try backup superblcok. 
1. Use the following command to find backup superblock location
    # /usr/local/sbin/dumpe2fs /dev/md0 | grep superblock
    Sample output:
    Primary superblock at 0, Group descriptors at 1-6
    Backup superblock at 32768, Group descriptors at
    Backup superblock at 98304, Group descriptors at
      
     
2. Now check and repair a Linux file system using alternate superblock # 32768:
    # e2fsck -b /dev/md0
    fsck (12-Jul-2007)
    e2fsck (12-Jul-2007)
    /dev/sda2 was not cleanly unmounted, check forced.
    Pass 1: Checking inodes, blocks, and sizescf
    
    Free blocks count wrong for group #241 (32254, counted=32253).
    Fix? yes
    
    /dev/sda2: ***** FILE SYSTEM WAS MODIFIED *****
    /dev/sda2: 59586/ files (0.6% non-contiguous), / blocks
3. Now try to mount file system using mount command:
    # mount /dev/md0 /share/MD0_DATA -t ext4

21. RAID fail - able to mount but data disappear
If the mount is OK, but data is disappear, unmount the RAID and run e2fsck again (can try backup superblock)
If still fail, try data recovery program (photorec, R-Studio) or contact data recovery company

22. RAID fail - RAID is degraded, read-only
When degraded, read-only status, there is more disk failure than the raid can support, need to help the user to check which disks are faulty if Web UI isn't helpful
        - Check klog or dmesg to find the faulty disks
Ask user to backup the data first
If disks looks OK, after backup, try "mdadm -CfR --assume-clean" to recreate the RAID
If above doesn't work, recreate the RAID

23. Degraded mode (read only) Failed drive (X)

24. NAS fail - Mount HDD(s) with another QNAP NAS
User can plug the HDD(s) to another same model name NAS to access the data
User can plug the HDD(s) to other model name NAS to access the data by perform system migration
note: TS-101/201/109/209/409/409U series doesn't support system migration
Since the firmware is also stored on the HDD(s), its firmware version may be different to the firmware on NAS.  Firmware upgrade may be required required after above operation

25. NAS fail - Access HDD(s) data with windows PC
For single or RAID-1 HDDs, user can plug one of the HDD to a PC (by USB, SATA or eSATA) and access the data through 3rd party software (ext2fsd, explore2fs, etc).  Check the following for detail.
Note: The file/folder name is in unicode(utf8)
TS-109/209 use non-standard ext3, need to use QNAP live CD to access the data
 Live CD
For other RAID configuration, user can use R-studio to mount the RAID and access the data. Check the following link for sample of RAID-0/5
        

26. NAS cannot boot correctly with HDD installed
If NAS cannot boot correctly with HDD installed.  With HDD, NAS boot without any problem.  This problem could be caused by faulty HDD, IO error on some blocks of HDD or corrupt configuration/system files.  
If user want to quickly access his data, we can try the following procedures: 
1. Power on the NAS without HDD installed
2. hot-plug HDDs into the NAS
3. Assemble the RAID
4. Copy data by winscp or backup to external drive
NOTE: arm-based NAS doesn't support sftp if boot without HDD.  Have to connect external drive for backup.  Find the following slide for procedures to mount a NTFS external drive

27. Mount NTFS/HPFS volume on ARM-based NAS when boot without HDD
Following is the procedure to mount NTFS/HPFS volume on an ARM platform NAS without initial HDD.
1. Download the following two files to the NAS.
2. Put nls_utf8.ko to /lib/modules/others
3. Put ufsd.ko to /lib/modules/misc
4. insmod nls_utf8.ko and insmod ufsd.ko
5. mount -t ufsd /dev/sdya1 /share/esata -o iocharset=utf8,dmask=0000,fmask=0111,force
NOTE: If the disk is larger than 2TB, the 1st partition may be GPT, so we have to mount the 2nd partition.

28. Data are deleted accidentally by user/administrator
1. User delete folders / files
Use photorec/R-studio/data recovery software to recovery data, Check the following link for using R-Studio
2. User remove the RAID volume
- see next slide
3. User format the RAID volume
- User photorec/data recovery software to recover data 
4. User perform Restore to Factory Default
- It will format RAID and reset all settings, same as 3.
5. User remove HDD(s) and cause RAID volume fail
- "mdadm -CfR --assume-clean" should work

29. User remove the RAID volume
# more /proc/mdstat   
    **Check if the RAID is really removed
# mdadm -E /dev/sda3   
    ** Check if the MD superblock is really removed
# mdadm -CfR --assume-clean /dev/md0 -l 5 -n 3 /dev/sda3 /dev/sdb3 /dev/sdc3   
    **Create the RAID, assume it is 3 HDDs raid-5
# e2fsck -y /dev/md0      
    **check file system, Assume "yes" to all questions.  If 64-bit, e2fsck_64
# mount /dev/md0 /share/MD0_DATA -t ext4    
    ** mount the RAID back
# vi raidtab   
    ** manually create the raid table
# rm /etc/storage.conf
    ** reflash the web UI volume display
# reboot
    ** Need to add the removed network share(s) back after reboot
Note: Only TS-x79, TS-809 series, and D510/D525 models with 5 or more bays support 64-bit commands.