mkfs.ext4

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Wat het doet

mkfs.ext4 is mke2fs -t ext4. ext4 can grow (also mounted) and shrink (only unmounted) with resize2fs. By default 5 % of the blocks are reserved for root (-m), so root can still work when users fill the disk.

Zo schrijf je het

mkfs.ext4 [OPTION]... DEVICE [SIZE]

Opties 30

Meest gebruikt

-L LABEL: Set a label (max 16 characters).
-m PERCENT: Reserved blocks for root (default 5).
-t TYPE: ext2, ext3 or ext4 (with mke2fs).
-T USAGE: Usage type from mke2fs.conf: news, largefile, largefile4, small, floppy.
-b SIZE: Block size (1024, 2048, 4096).
-i BYTES: Bytes per inode (smaller = more inodes).
-N NUMBER: Number of inodes.
-I SIZE: Inode size.
-U UUID: Set the UUID.
-O FEATURES: Turn features on or off (^feature = off), like ^has_journal.
-E OPTIONS: Extended options: stride=, stripe_width=, lazy_itable_init=, nodiscard …
-j: Create a journal (ext3).
-J OPTIONS: Journal options (size=, device=).
-e continue|remount-ro|panic: What to do on errors.
-c: Check for bad blocks first.
-l FILE: Read bad blocks from a file.
-g N, -G N: Blocks per group / groups per flex group.
-C SIZE: Cluster size (bigalloc).
-d DIR: Copy this folder into the new file system.
-M DIR: Last mounted directory.
-o OS: Creator OS.
-r REVISION: File system revision.
-S: Write only superblock and group descriptors (rescue, dangerous).
-D: Use direct I/O.
-z FILE: Save an undo file.
-n: Dry run: show what would happen.
-F: Force.
-q: Quiet.
-v: Verbose.
-V: Show the version.

Voorbeelden 10

$ als gewone gebruiker# als root (of met sudo)

1Create ext4
```
#mkfs.ext4 /dev/vdb2
```
Asks before overwriting an existing file system.
2With a label
```
#mkfs.ext4 -L backup /dev/vdb2
```
Mount with LABEL=backup.
3Less reserved space on a data disk
```
#mkfs.ext4 -m 1 /dev/vdb2
```
1 % instead of 5 % (big disks waste a lot with 5 %).
4Many small files
```
#mkfs.ext4 -T small /dev/vdb2
```
More inodes (mail or cache folders).
5Large files only
```
#mkfs.ext4 -T largefile4 /dev/vdb2
```
Fewer inodes, more space for data.
6Dry run
```
#mkfs.ext4 -n /dev/vdb2
```
Shows the backup superblock positions — useful for repair.
7ext3 or ext2
```
#mke2fs -t ext3 /dev/vdb3
```
Older formats, for old systems.
8Fast create on big devices
```
#mkfs.ext4 -E lazy_itable_init=1,nodiscard /dev/vdb2
```
Finishes the inode tables in the background.

9Check the result

#dumpe2fs -h /dev/vdb2 | grep -E 'volume name|Reserved block|Inode count'

Settings of the new file system.

10Change settings later
```
#tune2fs -m 1 -L data2 /dev/vdb2
```
No need to recreate.

Bestanden

/etc/mke2fs.conf: Defaults and usage types.

Exitcodes

0 :: Done. 1 :: Error.

`mkfs.ext4`

Wat het doet

Zo schrijf je het

Opties 30

Voorbeelden 10

1Create ext4

2With a label

3Less reserved space on a data disk

4Many small files

5Large files only

6Dry run

7ext3 or ext2

8Fast create on big devices

9Check the result

10Change settings later

Bestanden

Exitcodes

Volledige handleiding

Wat het doet

Zo schrijf je het

Opties 30

Voorbeelden 10

1Create ext4

2With a label

3Less reserved space on a data disk

4Many small files

5Large files only

6Dry run

7ext3 or ext2

8Fast create on big devices

9Check the result

10Change settings later

Bestanden

Exitcodes

Verwante commando's

Gebruikt in deze lessen

Gebruikt in deze labs

Volledige handleiding

`mkfs.ext4`