Create and configure file systems
Creating and mounting
mkfs.xfs /dev/vg/lv, mkfs.ext4, mkfs.vfat, and mkswap create filesystems; XFS and ext4 are the workhorses. Mount with mount /dev/vg/lv /mnt/data, then inspect with findmnt, df -hT, xfs_info, and tune2fs -l. Unmount with umount /mnt/data; if it reports 'target is busy', locate the holder with lsof +D /mnt/data or fuser -vm /mnt/data.
/etc/fstab
Six fields: device (prefer UUID=), mount point, filesystem type, options, dump (0), and pass (0 for XFS and swap, 1 or 2 for ext). Common options are defaults, noatime, ro, nofail, and x-systemd.automount. Run mount -a after every edit so a typo surfaces while the system is still up.
Extra features
ACLs extend the permission model: setfacl -m u:bob:rw file, getfacl file, and default ACLs applied to a directory govern files created inside it. Special bits: setgid on a directory makes new files inherit the group; sticky (+t) on /tmp stops non-owners from deleting files. NFS mounts (mount -t nfs server:/export /mnt) and autofs also appear regularly.
Traps: the pass field must be 0 for XFS and swap or boot complains. A missing mount point directory causes a boot failure, so create it first. Options in fstab are comma separated with no spaces. A UUID copied from the wrong source will not match blkid output.
Rule of thumb: after any fstab change, run mount -a then findmnt --verify.
Worked example:
UUID=1a2b-3c4d /data xfs defaults 0 0