High Availability broken-Node unclean

Something that happened out of the blue today.
My slave node went down.
It is on standby and when I want to bring it back online, the GUI says it has been set to online, but nothing changes and pcs status says node is unclean.
Any ideas?

[[email protected] ~]# pcs status
Cluster name:
Last updated: Thu Feb 26 18:05:22 2015
Last change: Thu Feb 26 16:15:36 2015 via crm_attribute on freepbx-a
Stack: cman
Current DC: freepbx-a - partition with quorum
Version: 1.1.10-14.el6-368c726
2 Nodes configured
22 Resources configured

Node freepbx-b: UNCLEAN (offline)
Online: [ freepbx-a ]

Full list of resources:

spare_ip (ocf::heartbeat:IPaddr2): Started freepbx-a
floating_ip (ocf::heartbeat:IPaddr2): Started freepbx-a
Master/Slave Set: ms-asterisk [drbd_asterisk]
Masters: [ freepbx-a ]
Stopped: [ freepbx-b ]
Master/Slave Set: ms-mysql [drbd_mysql]
Masters: [ freepbx-a ]
Stopped: [ freepbx-b ]
Master/Slave Set: ms-httpd [drbd_httpd]
Masters: [ freepbx-a ]
Stopped: [ freepbx-b ]
Master/Slave Set: ms-spare [drbd_spare]
Masters: [ freepbx-a ]
Stopped: [ freepbx-b ]
spare_fs (ocf::heartbeat:Filesystem): Started freepbx-a
Resource Group: mysql
mysql_fs (ocf::heartbeat:Filesystem): Started freepbx-a
mysql_ip (ocf::heartbeat:IPaddr2): Started freepbx-a
mysql_service (ocf::heartbeat:mysql): Started freepbx-a
Resource Group: asterisk
asterisk_fs (ocf::heartbeat:Filesystem): Started freepbx-a
asterisk_ip (ocf::heartbeat:IPaddr2): Started freepbx-a
asterisk_service (ocf::heartbeat:freepbx): Started freepbx-a
Resource Group: httpd
httpd_fs (ocf::heartbeat:Filesystem): Started freepbx-a
httpd_ip (ocf::heartbeat:IPaddr2): Started freepbx-a
httpd_service (ocf::heartbeat:apache): Started freepbx-a
Clone Set: ClusterMon-SMTP-clone [ClusterMon-SMTP]
Started: [ freepbx-a ]
Stopped: [ freepbx-b ]

Other Data state: diskless

I also can’t ssh into my slave node anymore.
So that is a more serious issue going on here!

Health Check:

That second machine is broken. ‘Read-only file system’. It appears to have had a disk failure.

A reboot MAY fix it?