What is Difference Between RHEL 6 & RHEL 7

This page would list out some of the major differences between RHEL 7 and 6 variants and key features in RHEL 7. Here we made some useful changes made in RHEL 7 over RHEL 6.

1. OS BOOT TIME

RHEL6: 40 sec

RHEL7: 20 sec

2. MAXIMUM SIZE OF SINGLE PARTITION

RHEL6: 50TB(EXT4)

RHEL7: 500TB(XFS)

3. BOOT LOADER

RHEL6:  /boot/grub/grub.conf

RHEL7: /boot/grupb2/grub.cfg

4. PROCESSOR ARCHITECTURE

RHEL6: It support 32bit & 64bit both

RHEL7: It only support 64bit

5. HOW TO FORMAT OR ASSIGN A FILE SYSTEM IN

RHEL6:      #mkfs.ext4   /dev/hda4

RHEL7:       #mkfs.xfs   /dev/hda3

6. HOW TO REPAIR A FILE SYSTEM IN

RHEL6:  #fsck -y /dev/hda3

RHEL7:  #xfs_repair /dev/hda3

7. COMMAND TO MANAGE NETWORK IN RHEL6 AND RHEL7

RHEL6:  #setup

RHEL7:  #nmtui

8. HOSTNAME CONFIGURATION FILE

RHEL6:    /etc/sysconfig/network

RHEL7:    /etc/hostname

9. DEFAULT ISO IMAGE MOUNT PATH

RHEL6: /media

RHEL7: /run/media/root

10. FILE SYSTEM CHECK

RHEL6:   e2fsck

RHEL7:   xfs_repair

11. RESIZE A FILE SYSTEM

RHEL6:   #resize2fs -p /dev/vg00/lv1

RHEL7:    #xfs_growfs  /dev/vg00/lv1

12. TUNE A FILE SYSTEM

RHEL6: tune2fs

RHEL7: xfs_admin

13. IPTABLES AND FIREWALL

RHEL6: iptables

RHEL7: firewalld

14. IPtables

To see firewall status in RHEL7

#firewall-cmd   –state

To see Firewall status in RHEL6

#service iptables status

To stop firewall in RHEL7

#systemctl stop firewalld.service

To stop firewall in RHEL6

#service iptables stop

15. COMMUNICATION BETWEEN TCP AND UDP IN BACK END

RHEL6: netcat

RHEL7: ncat

16. INTERFACE NAME

RHEL6: eth0

RHEL7: ens198(N)

17. COMBINING NIC

RHEL6: Network Bonding

RHEL7: Team Driver

18. NSF Server Version

RHEL6:  NFSv2

RHEL7:  NFSV4

19. DATABASE USED

RHEL6: Mysql

RHEL7: mariaDB

RHEL7 also support Mysql

20. MANAGING SERVICES

RHEL6:

#service sshd restart

#chkconfig sshd on

RHEL7:

#systemctl restart sshd

#systemctl enable shhd

21. File System.

RHEL6 default file system is ext4

xfs is RHEL7 default file system.

22. Kernel Version

RHEL6 default kernel version is 2.6 while RHEL7 is 3.10

23. UID Allocation

In RHEL6 default UID assigned to users would start from 500 while in RHEL7 it’s starting from 1000.
But this can be changed if required by editing /etc/login.defs file.

24. Maximum supported File Size.

In RHEL6 maximum file size of an individual file can be up to 16TB while in RHEL7 it can be up to 500TB which is very large in comparison to RHEL6.

25. Maximum Supported File System Size.

In RHEL6 maximum file system size=16TB (for 64bit Machine) and 8TB (for 32 bit machine). While in RHEL7 maximum file system size is 500TB.

Also keep in mind that RHEL does not support XFS on 32-bit machines.

26. Change in file system structure.

In rhel6 /bin,/sbin,/lib and /lib64 are usually under /

In rhel7, now /bin,/sbin,/lib and /lib64 are nested under /usr.

The /tmp directory can now be used as a temporary file storage system (tmpfs)

27. Space Required to Installing RHEL7?

Now if you want to install RHEL7 in your machine, RedHat recommends minimum 5 GB of disk space to install this release of RHEL series for all supported architectures.

28. .Hostname lookup and setup 

In rhel5 and rhel6 versions, we can edit file /etc/sysconfig/network to set hostname but in rhel7 we can directly change the hostname using below commands.

1. hostnamectl
2. nmtui
3. nmcli

Example:

in RHEL6              #hostname

in RHEL7              #hostnamectl  status   and #hostname

29. Few More notable changes in RHEL 7.

• Netstat and ifconfig commands also disappeared from RHEL7 but it can be used by installing net-tools.
• The move from sysvinit to systemd is one of most important change that has been made and which is a matter of concerned.
• Command tail -n is replaced by journalctl -n
• Command tail -f is replaced by journalctl -f
• For displaying kernel messages instead of dmesg now in RHEL7 we use journalctl –k