Ext4
ext4 (2008) journaling file system or fourth extended filesystem is a journaling file system for Linux and it is the default file system for many Linux distributions such as Ubuntu and Debian. RHEL default fs is XFS.
Since Linux kernel 4.1 on June 2015[1], ext4 natively supports file encryption
Basic commands
mkfsandmke2fs- Creating an ext4 filesystem: (by default since 2010 will do a quick and lazy initialization [2])
- Creating an ext4 in a disk
mkfs.ext4 /dev/sdX
- Creating an ext4 FS in an LV:
mkfs.ext4 /dev/vg01/lv01
- To prevent lazy initialization
mkfs.ext4 -E lazy_itable_init=0,lazy_journal_init=0 /dev/mapper/fc-root[3]
- resize2fs (See also: xfs_growfs)
resize2fs
resize2fs[4] file system resizer for ext2/ext3/ext4 (resize2fs /dev/mapper/VolGroup-lv_root). Online resize (expand) is supported in resize2fs since 2006[5].[6]. resize2fs code: https://github.com/tytso/e2fsprogs/blob/master/resize/resize2fs.c. See also: ext2online
EXT4 Features timeline
- 2020 ext4 fast commit support (Linux Kernel 5.10 December 2020)
- 2015 File encryption
- 2010 Lazy Initialization[7]
- 2006 Online resize (expand) support
- 2006 Extents replace the traditional block mapping scheme used by
ext2andext3
Activities
Basic
- Create an file ext4 system using:
mkfs.ext4 - Create an ext4 file system an mount it using systemd: https://codingbee.net/rhcsa/rhcsa-mount-filesystems-during-boot-time-using-systemd
Advanced
- Configure an LVM Volume with an ext4 filesystem: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/high_availability_add-on_administration/s1-lvmsetupnfs-haaa
- Learn about Lazy initialization feature of ext4: https://www.thomas-krenn.com/en/wiki/Ext4_Filesystem#Lazy_Initialization
- Review ext4 journalctl logs
Mount options
Related terms
See also
ext4e2fsck,,fsck.ext4, superblock, inode, block size, mkfs.ext4 tune2fswipefs,resize2fsstat,extents, Review ext4 journalctl logs. Read-only file system,virt-resize, ACL- File systems: clustered file system,
tune2fsmkfs.ext4,superblock, e2fsck,resize2fs,mount,df,umount, UUID,fstab - File systems:
ext4,XFS,ZFS,btrfs,wipefs,findfs,HDFS,overlay,aufs,virt-filesystems, Windows: (FAT, NTFS, ReFS), GPFS, squashfs, Ecryptfs, Encfs, FUSE, VMFS, Comparison of distributed file systems, Userspace filesystem, Resize filesystem size - File system,
du, df, find, ls, mkdir, touch, locate - ZFS, LVM, mdadm, fdisk and partitions
- XFS,
attr,xfs_growfs,xfs_info, mkfs.xfs - ext2online
- JFS2,
mkfs.jfs(Linux),jfsutilsandxfs_growfs[8] - File systems:
mount,umount,findmnt,find,swapon,swapoff,UUID, blkid, mount options:/etc/fstab,udisksctl mount,guestmount,/proc/mounts,fstrim,systemd-mount,defaults sudo,id,visudo,useradd,userdel,usermod,groups,passwd,chown,chmod,chgrp,groupadd,groupdel, Passwordless sudo, passwd (package),sudo --helpsmartctl
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