`mkfs.ext3 /dev/sdb1` builds an ext3 filesystem on that partition. Select the TWO commands that build exactly the same filesystem there.
LPIC-1 Exam 101-500, objective 104. Devices, Linux filesystems, filesystem hierarchy standard hard
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The options
Choose 2.
Correct mkfs -t ext3 /dev/sdb1
Correct. mkfs builds nothing itself. It appends the type to its own name and executes mkfs.ext3, so this is the same program doing the same work, reached through the front end.
Correct mke2fs -t ext3 /dev/sdb1
Correct. mke2fs is the program that mkfs.ext2, mkfs.ext3 and mkfs.ext4 all are. Called under one of those names it takes the type from the name; called as mke2fs it takes it from -t, and the result is identical.
Not correct mke2fs /dev/sdb1
Wrong. Invoked under its own name with no -t, mke2fs falls back to the default type — ext2 on a stock configuration — so what you get is a filesystem with no journal.
Not correct tune2fs -j /dev/sdb1
Wrong. -j adds a journal to an ext2 filesystem that already exists, which is how an ext2 filesystem is converted to ext3 in place. It modifies a filesystem rather than creating one.
Not correct mkfs.ext4 -O ^has_journal /dev/sdb1
Wrong, and a trap worth recognising. Turning the journal feature off does not turn ext4 into ext3: the result is an ext4 filesystem, extents and all, that merely lacks a journal.
Why
The ext tooling is one program wearing several names, plus a front end that owns no filesystem knowledge at all. mkfs appends the type to its own name and runs mkfs.<type>, and with no -t it uses its own default type, currently ext2. mkfs.ext2, mkfs.ext3 and mkfs.ext4 are all mke2fs, which reads the name it was invoked by to choose a default and lets -t override it — which is why `mke2fs -t ext3` and `mkfs.ext3` are the same command. The type is not cosmetic: it selects the stanza of /etc/mke2fs.conf that supplies the default feature set, which is where the journal comes from.
Where this comes from
- Cited
- manual page mke2fs(8)
Practise this
Reading one question is not practice. The trainer will draw a short set from objective 104 and space the ones you get wrong.
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