read-only file system

I am suddenly not allowed to write on the file system. I login via ssh and even tried in superuser mode. 

Got theses messages:

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login as: Vivek
Vivek@192.168.1.7's password:

Welcome to ReadyNASOS 6.9.0

Last login: Sun Nov 5 19:55:32 2017 from 192.168.1.3
Vivek@viveks-nas:~$ pwd
/home/Vivek
Vivek@viveks-nas:~$ mkdir temp
mkdir: cannot create directory ‘temp’: Read-only file system

Vivek@viveks-nas:/data/Backup$ cd IMAC27/
Vivek@viveks-nas:/data/Backup/IMAC27$ mkdir temp
mkdir: cannot create directory ‘temp’: Read-only file system
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The log files  from NAS are  attached here. Kindly help in this matter.

thanks

Firmware: 6.9.0