Where Are Linux Filesystem Mounts Configured?
Where Linux mounts filesystems from /etc/fstab, how entries work, and the commands that validate them.
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Linux mounts filesystems at boot from /etc/fstab: one line per mount with device, mount point, type, options, dump and pass fields. A typo here strands the boot at emergency shell, which is why the file demands more respect than its simplicity suggests.
Modern systems layer automounts, systemd mount units and desktop helpers over it, but fstab remains the canonical static map. Back it up before editing (one cp buys total safety), validate with findmnt, and keep a live USB nearby the first time you touch root entries.
Where fstab stores this, by platform
/etc/fstab
One line per filesystem; fields are device, mountpoint, fstype, options, dump, pass. Validate with findmnt --verify. List UUIDs with blkid. Back up with cp before editing.
Frequently asked questions
How do I check fstab without rebooting?
Run findmnt --verify (or mount -a) before rebooting: it parses fstab and reports bad UUIDs, missing mount points and option typos without mounting anything. Boot from live media and fix the file if a bad entry already strands the boot.
UUID or device name: which should I use?
Use blkid to list UUIDs and write those instead of /dev/sdX names, which reorder across boots and hardware changes. Copy the exact UUID string: one transposed character mounts the wrong disk or nothing at all.
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