Failed Xraid Needs Recovery

Hello All.
Overnight I had a major failure on my NAS. The X-raid has dropped. The
Raid now shows as unknown. I am requesting help for this failure. 


[23/06/17 23:51:14 AEST] notice:disk:LOGMSG_ADD_DISK Disk
Model:ST2000DM001-1ER164 Serial:Z4Z1RPCQ was added to Channel 1 of the head
unit.
[23/06/17 23:51:15 AEST] warning:volume:LOGMSG_HEALTH_VOLUME Volume data
health changed from Redundant to Dead.
[23/06/17 23:51:26 AEST] warning:disk:LOGMSG_DELETE_DISK Disk
Model:ST2000DM001-1ER164 Serial:Z4Z1RPCQ was removed from Channel 1 of the
head unit.
[23/06/17 23:51:30 AEST] warning:disk:LOGMSG_DELETE_DISK Disk
Model:ST2000VX008-2E3164 Serial:Z52AZ56J was removed from Channel 3 of the
head unit.
[23/06/17 23:55:24 AEST] err:disk:LOGMSG_ZFS_DISK_STATUS_CHANGED Disk in
channel 4 (Internal) changed state from ONLINE to FAILED.
[23/06/18 00:05:12 AEST] err:disk:LOGMSG_ZFS_DISK_STATUS_CHANGED Disk in
channel 1 (Internal) changed state from ONLINE to FAILED.
[23/06/18 05:43:36 AEST] warning:disk:LOGMSG_DELETE_DISK Disk
Model:ST2000DM001-1ER164 Serial:Z4Z2HSZT was removed from Channel 4 of the
head unit.
[23/06/18 05:46:50 AEST] info:system:LOGMSG_READYNASD_ABORTED_NOINFO
ReadyNASOS service or process was restarted.
[23/06/18 05:47:09 AEST] info:system:LOGMSG_START_READYNASD ReadyNASOS
background service started.