Today in this tutorial i am going to mention the few important difference between RHEL6 and RHEL7 version.If someone had already completed RHCE certification on RHEL6 version this article will help him/her to easily learn the RHEL7 and get adjusted with this Latest RedHat Enterprise Linux OS.The major issue with new OS is that we don’t know whether our previous command will work on this OS or not or we have to learn it from start once again.Here i want you to confirm that you dont need to do RHCE Training again if you already know RHEL6.

TO MAKE YOUR TASK EASY TO UNDERSTAND SOME BASIC DIFFERENCE BETWEEN RHEL6 AND RHEL7 I HAVE WRITTEN THIS ARTICLE AND THIS ARTICLE WILL MAKE YOUR TASK EASY AND YOU CAN EASILY GET FAMILIAR WITH YOUR NEW RHEL7.

[1]ON THE BASIS OF RELEASE DATE.

RELEASE DATE OF RHEL6 IS 10th NOV 2010.

RELEASE DATE OF RHEL7 IS 10TH JUNE 2014.

Hence RHEL7 is latest os.

 

[2]DIFFERENCE ON THE BASIS OF OPERATING SYSTEM NAMES

If you want to see this use this command

#cat /etc/redhat-release

RHEL6 : REDHAT ENTERPRISE LINUX (SANTIGO)

RHEL7: REDHAT ENTERPRISE LINUX (MAIPO)

 

[3]KERNEL VERSION

RHEL6: 2.6.32

RHEL7:  3.0.10

 

[4] OS BOOT TIME

RHEL6: 40 sec

RHEL7: 20 sec

 

[5]MAXIMUM SIZE OF SINGLE PARTITION

RHEL6: 50TB(EXT4)

RHEL7: 500TB(XFS)

 

[6] BOOT LOADER

RHEL6:  /boot/grub/grub.conf

RHEL7: /boot/grupb2/grub.cfg

 

[7]PROCESSOR ARCHITECTURE

RHEL6: It support 32bit & 64bit  both

RHEL7: It only support 64bit

 

[8]HOW TO FORMAT OR ASSIGN A FILE SYSTEM IN

RHEL6:      #mkfs.ext4   /dev/hda6

RHEL7:       #mkfs.xfs   /dev/hda6

 

[9]HOW TO REPAIR A FILE SYSTEM IN

RHEL6:  #fsck -y /dev/hda6

RHEL7:  #xfs_repair /dev/hda6

 

[10]COMMAND TO MANAGE NETWORK IN RHEL6 AND RHEL7

RHEL6:  #setup

RHEL7:  #nmtui

 

[11]HOSTNAME CONFIGURATION FILE

RHEL6:    /etc/sysconfig/network

RHEL7:    /etc/hostname

 

[12]DEFAULT ISO IMAGE MOUNT PATH

RHEL6: /media

RHEL7: /run/media/root

 

[13]FILE SYSTEM CHECK

RHEL6:   e2fsck

RHEL7:   xfs_repair

 

[14]RESIZE A FILE SYSTEM

RHEL6:   #resize2fs  -p /dev/vg00/lv1

RHEL7:    #xfs_growfs  /dev/vg00/lv1

 

[15]TUNE A FILE SYSTEM

RHEL6: tune2fs

RHEL7: xfs_admin

 

[16]IPTABLES AND FIREWALL

RHEL6: iptables

RHEL7: firewalld

 

NOTE:

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

 

 

[17]COMMUNICATION BETWEEN TCP AND UDP IN BACK END

RHEL6: netcat

RHEL7: ncat

 

[18]INTERFACE NAME

RHEL6: eth0

RHEL7: ens198(N)

 

[19]COMBINING NIC

RHEL6: Network Bonding

RHEL7: Team Driver

 

[20]NSF Server Version

RHEL6:  NFSv2

RHEL7:  NFSV4

 

 [21]DATABASE USED

RHEL6: Mysql

RHEL7: mariaDB

Altough RHEL7 also support Mysql

[22]MANAGING SERVICES

RHEL6:

#service sshd restart

#chkconfig sshd on

RHEL7:

#systemctl restart sshd

#systemctl enable shhd

[23]ON Basis of file System.

RHEL6 defualt file system is ext4 while xfs is RHEL7 default file system.

 

[24] Kernel Version

RHEL6 default kernel version is 2.6 while RHEL7 is 3.10

[25]Kernel Code Name
RHEL6 kernel code name is Santiago while RHEL7 kernel code name is Maipo.

[26]UID Allocation

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

 

[27]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.

[28]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 thatRHEL does not support XFS on 32-bit machines.

[29]change in file system structure.
in rhel6 /bin,/sbin,/lib and /lib64 are usually under / while in rhel7 now they are nested under /usr.

 

NEW FEATURES OF RHEL7 :

 

1. Space Required to Install 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.
2. Boot Loader in RHEL7
A new book loader GRUB2 has been introduced in RHEL 7.It comes with new features.

 

3.RHEL7 GRUB2 Configuration File:
# vim /boot/grub2/grub.cfg

 

4. New Installer you can say Redesigned Anaconda Version
Red Hat Enterprise Linux 7 has and redesigned Anaconda version.
It contains many improvements in system installation.

 

5. firstboot Implementation
RHRL 7 replaces firstboot with the Initial Setup utility, initial-setup, for better interoperability with the new installer.

 

6. Changes in File System Layout
RHEL7 introduces two major changes to the layout of the file system.
The /bin, /sbin, /lib and /lib64 directories are now under the /usr directory.
The /tmp directory can now be used as a temporary file storage system (tmpfs)

 

7. Network Configuration utility(ncat)
A new networking utility ncat has been introduced in RHEL 7 which replaces netcat.
8. New Version of Apache
RHEL 7 is coming with apache 2.4

 

9. Chrony – A new Package Introduced
Chrony is introduced as new NTP client provided in the chrony package. Chrony does not provides all features available in old ntp client (ntp). So ntp is still provided due to compatibility.

10. HAProxy
HAProxy has been introduced in RHEL 7. It is a TCP/HTTP reverse proxy that is well-suited to high availability environments.

 

11.hostname lookup and setup 

In rhel5 and rhel6 version of Linux we need to edit file /etc/sysconfig/network to set hostname but in rhel7 its not so.

Now in RHEL7 we can directly chnage the hostname using below commands.

1. hostnamectl
2. nmtui
3. nmcli

HOW TO SEE HOSTNAME IN RHEL6 and RHEL7

in RHEL6              #hostname

in RHEL7              #hostnamectl  status   and #hostname

 

12.Introduction of Docker in RHEL7.

13.Device Hotplug Removed from RHEL7.

14.RHEL7 does not provide 32 bit iso.RHEL7 will not natively support

32-bit hardware architecture.

 

15.RHEL7 use OPenJDK7 as the default java development kit.

 

 

There are other so many changes between RHEL previous versions and RHEL7.

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