failed array in LVM

unmount fs:

]# umount /data

check size of the failed array

]# cat /proc/mdstat

md127 : active raid1 sdi1[3]
      3906886464 blocks super 1.2 [2/1] [_U]
      bitmap: 30/30 pages [120KB], 65536KB chunk

size in gigabytes:
 $((3906886464/1024/1024)) = 3725(G)

check filesystem and reduce the LV

]# e2fsck -f /dev/mapper/titdata1-data1

]# lvreduce --resizefs -L -3800G /dev/mapper/titdata1-data1

reduce CG :

]#  vgreduce titdata1 /dev/md127

   --- failed, because the array was originally /dev/md1 (this is also specified in /etc/mdadm.conf)

]# ln /dev/md127 /dev/md1

free /dev/md1 in VG

]# pvmove /dev/md1
]# vgreduce titdata1 /dev/md1
]# lvextend -l +100%FREE /dev/mapper/titdata1-data1
]# resize2fs /dev/mapper/titdata1-data1
]# e2fsck -f /dev/mapper/titdata1-data1