Here my config :
DNS-323 containt 2 disks Western Digital 2TB configurated as RAID 0 to get 4 TB storage.
I try a lot of free programs but no success to restore anything. I found UFS Explorer. It's a multi platform recover program this can be run as shareware, you can use search option with no restriction but you need to purchase license to can be able to restore a file (big than 64 kb). This license is +/- 50 euros - $ 70,00.
How to recover deleted files :
1. Format a PC by installing Ubuntu on it (I use Kubuntu 10.10 - 64 bit edition for this). My PC has a 120 GB Disk, 4 GB memory and AMD Athlon 64 X2. When you install ubuntu make manual patition. Chose a 5 GB partition for system file and a big partition +100 GB for swap partition. All the process use memory... Connect this pc to internet. More memory you have, less time it takes for process and less swapping.
2. After Ubuntu's installation. Power down your PC.
3. Take your nas DNS-323 and remove the 2 disks. Don't forget to write order of these disks.
4. Install this 2 removed disks on you pc on same order and power on your pc.
5. On Ubuntu take a command prompt and enter :
$ > sudo -i (put your password)
# > apt-get install mdadm
# > mdadm --assemble --scan
# > cat /proc/mdstat
In this state you can see something like this :
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid0 sdb1[0] sdc1[1]
........
6. Download program from UFS site : http://www.ufsexplorer.com/download.php select 64 bit version. No license is required to search deleted files but need for restore these.
7. Install this program in command prompt :
# > dpkg -i "path of your downloaded file"
8. Now you cant go to graphical interface and run UFS this is located on system menu.
9. Select a non visible partition : /dev/md0
10. Run "recover" command. Be carefull, this recovery process take 3 complete days... for 2 X 2 TB disks.
11. You will see all files it founds but no more names of these files...
12. After, you need to purchase a license if you want to restore files...
13. Plug a removable storage or another disk (without turn off pc of course) and save recover files on this new storage. This process will take a lot of time too..
Hope this help.