NAS 326 lack of access

As Mijzelf wrote, replacing the disk implies losing all data existing on the RAID0 volume.

Having access to it via ssh .... you should try unmounting the volume and run a filesystem check against it. As it is shown in the screenshot the disks status is shown good but the volume status is not good. I guess by the look of the first picture the volume it is also not mounted.

You have restarted the system - this implies the operating system must have already ran a filesystem check and the result must be in the available logs.

Try from terminal the dmesg command. Before running any commands make sure you log what you do - use a terminal program that allows logging and makke sure it is enabled the logging.

To determine if it is mounted or not

1. Run mount command. It should output something similar to this if any ext4 type filesystem is mounted:

Further actions depend on actually what commands the user under which you login via ssh has access to and what it is available on the installed operating system.

About mounting/unmounting filesystems and what the output of mount means:

Commands to consider:

e2fsck or fsck.ext4 or fsck - an fsck program that checks for and corrects inconsistencies

Manual pages should be read and understood. The fsck command should first be run in read only mode.

It is plenty of information on how to deal with your problem on the Internet. Take your time - if you need the data.