ReadyNAS Ultra 6 resync fails #25422511

[Fertrius]

Hello!

First of all there is 6x WD 3Tb disks and one of them become "dead".
I have 4x Seagate NAS HDD 4Tb, someone already try and successfully install them to Ultra 6.
When I plug in 3 box new disk it's start to resync volume, but after 10-17% says that:

RAID sync finished on volume C. The array is still in degraded mode, however. This can be caused by a disk sync failure or failed disks in a multi-parity disk array.

and turn state to :

On life support - access to volume disabled. To restore volume, shutdown this device, reconnect the disk(s) if they had been inadvertently disconnected, and power the device back on. To avoid permanently rendering the disk unusable, do not reconnect the disk(s) while the power is on.

In Health I can see that disk in box 3 become a "spare" and a disk in box 4 become "dead".
If I removing 4 box disk system cant find a data volume

What can I do?

[mdgm-ntgr]

Do you have a backup?

[Fertrius]

That is a main problem, no backup.

OK. Turn off NAS for few hours, after return home power on it again, so one more time:

[Fertrius]

Failed.

also I start a check

***** File system check forced at Mon Jul 13 19:07:57 EEST 2015 *****
fsck 1.42.12 (29-Aug-2014) e2fsck 1.42.12 (29-Aug-2014)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/c/c: 1242025/228395008 files (7.9% non-contiguous), 1955307362/3654303744 blocks

The last message "7.9% non-contiguous" meen that I lost some of data?

[mdgm-ntgr]

This sounds like a situation in which you should contact support and consider the paid options for getting a tech to look at it.