Nel frattempo mi ha scritto l'assistenza Synology:
Thank you for contacting Synology support.
I think your volume staying at "read only" mode at the moment,
I suggest you backup data asap, then use all healthy disk to recreate volume avoiding data lose
(because it have bad sectors& file system error now).
Using clean disk to create volume will fix file system errors.
How to check the hard disk(s):
 You may take out the disks and connect them to your desktop/laptop computer, and then run the manufacturer's diagnostic tools (see below) to confirm the health status of the disks. Change defective HDs if any.
[Samsung HDD: ES-tool]http://www.samsung.com/global/business/ ... _Tool.html
[WD HDD: Lifeguard]http://download.wdc.com/windlg/WinDlg_124.zip
[Seagate HDD: Seatool]http://www.seagate.com/support/downloads/seatools/
[Hitachi HDD: Drive Fitness Test]http://www.hitachigst.com/support/downloads/
You may also use http://crystalmark.info/software/Crysta ... dex-e.html
to check the health of your disk. If you see any non-zero raw values for ID 1 (for WD and Samsung disks) and ID 5/197/198 (for all disks) in the disk S.M.A.R.T. info, the disk is defective, please replace with a healthy one. Please refer to http://en.wikipedia.org/wiki/S.M.A.R.T
. for more information.
 If you can log on DSM WebGUI ( If not, please just ignore this way ), please run the DSM S.M.A.R.T tool (Storage Manager > HDD/SSD > S.M.A.R.T. test > Extended Test) to scan the disks.