persistent disks

$ lsblk
NAME   MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda      8:0    0  10G  0 disk
└─sda1   8:1    0  10G  0 part /
sdb      8:16   0  50G  0 disk

$ sudo mkfs.ext4 -m 0 -F -E lazy_itable_init=0,lazy_journal_init=0,discard /dev/sdb
mke2fs 1.43.4 (31-Jan-2017)
Discarding device blocks: done             
Creating filesystem with 13107200 4k blocks and 3276800 inodes
Filesystem UUID: 5b8f75c2-55b0-4d88-a159-ef6f016458df
Superblock backups stored on blocks:
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
        4096000, 7962624, 11239424

Allocating group tables: done   
Writing inode tables: done   
Creating journal (65536 blocks): done
Writing superblocks and filesystem accounting information: done