bytecommander@BC-AlkaliMetal:~$ sudo mkswap /dev/sda4
[sudo] password for bytecommander:
Setting up swapspace version 1, size = 7,6 GiB (8095002624 bytes)
no label, UUID=67cad2f7-bc02-4610-bb95-56a80e8f68a8
bytecommander@BC-AlkaliMetal:~$ sudo service cryptdisks reload
bytecommander@BC-AlkaliMetal:~$ sudo service cryptdisks-early reload
bytecommander@BC-AlkaliMetal:~$ ll /dev/mapper
total 0
drwxr-xr-x 2 root root 60 Aug 29 04:09 ./
drwxr-xr-x 20 root root 4780 Aug 29 04:10 ../
crw------- 1 root root 10, 236 Aug 29 04:09 control