luks encryption

I am trying to create an encrypted luks partition on my system. My first attempt worked, but the next time I wanted to use the encrypted partition
I didn’t work, I later found that the name i called it was missing from the /dev/mapper/ directory.

So I started again after wiping the partition, I went through the process when it come to formatting mkfs.ext4 /dev/mapper/name
I got this message

“Device size reported to be zero. Invalid partition specified or partition table wasn’t reread after running fdisk due to a modified partition being busy and in us. You need to reboot to reread your partition table.”

Why does the file disappearing from the mapper directory?
fdisk shows that it is a valid partition the size is not zero. I did reread the partition with the ‘w’ and rebooted the computer, any ideas?

Thank you for your help

There is not enough information here to pinpoint a problem. How did you create the partition, what commands did you use to encrypt and open it etc?

What is the partition type? Is it lvm or a plain partition? What happens when you luksOpen it? A name missing from /dev/mapper usually means that the device/partition was not opened with that name, if it was opened at all.

cryptsetup -v isLuks /dev/<partition>
cryptsetup -v luksDump /dev/<partition>
cryptsetup -v status <name>
cryptsetup -v luksOpen /dev/<partition> <name>
cryptsetup -v status <name>

Thanks, markdd I have solved the problem