RHEL6 Vs RHEL7

Release Name

RHEL 6 – Santiago
RHEL 7 – Maipo

Gnome Version

RHEL 6 – GNOME 2
RHEL 7 – GNOME 3.8

KDE Version

RHEL 6 – KDE 4.1
RHEL 7 – KDE 4.6

NFS Version

RHEL 6 – NFS 4
RHEL 7 – NFS 4.1. NFS V2 is deprecated in RHEL 7

Samba Version

RHEL 6 – SMB 3.6
RHEL 7 – SMB 4.4

OS BOOT TIME

RHEL6: 40 sec

RHEL7: 20 sec

MAXIMUM SIZE OF SINGLE PARTITION

RHEL6: 50TB(EXT4)

RHEL7: 500TB(XFS)

BOOT LOADER

RHEL6:  /boot/grub/grub.conf

RHEL7: /boot/grupb2/grub.cfg

PROCESSOR ARCHITECTURE

RHEL6: It support 32bit & 64bit both

RHEL7: It only support 64bit

HOW TO FORMAT OR ASSIGN A FILE SYSTEM IN

RHEL6:      #mkfs.ext4   /dev/hda4

RHEL7:       #mkfs.xfs   /dev/hda3

HOW TO REPAIR A FILE SYSTEM IN

RHEL6:  #fsck -y /dev/hda3

RHEL7:  #xfs_repair /dev/hda3

COMMAND TO MANAGE NETWORK IN RHEL6 AND RHEL7

RHEL6:  #setup

RHEL7:  #nmtui

HOSTNAME CONFIGURATION FILE

RHEL6:    /etc/sysconfig/network

RHEL7:    /etc/hostname

DEFAULT ISO IMAGE MOUNT PATH

RHEL6: /media

RHEL7: /run/media/root

FILE SYSTEM CHECK

RHEL6:   e2fsck

RHEL7:   xfs_repair

RESIZE A FILE SYSTEM

RHEL6:   #resize2fs -p /dev/vg00/lv1

RHEL7:    #xfs_growfs  /dev/vg00/lv1

Run Levels

RHEL 6 – runlevel 0 – Power Off
runlevel 1 – Single User Mode
runlevel 2 – Multi User without Networking
runlevel 3 – Multi User CLI
runlevel 4 – Not USed
runlevel 5 – GUI Mode
runlevel 6 – Restart

RHEL 7 – There is no run levels in RHEL 7. Run levels are called as targets
Poweroff.target
rescue.target
multi-user.target
graphical.target
reboot.target

UID Information

RHEL 6 – Normal User UID will start from 500 to 65534
System Users UID will start from 1 to 499

RHEL 7 – Normal User UID start from 1000 – 65534
System Users UID will start from 1 to 999Because Services are increased compare to RHEL 6

By Pass Root Password Prompt

RHEL 6 – append 1 or s or init=/bin/bash to Kernel command line
RHEL 7 – Append rd.break or init=/bin/bash to kernel command line

Rebooting and Poweroff

RHEL 6 – poweroff – init 0
reboot – init 6

RHEL 7 – systemctl poweroff
systemctl reboot

YUM Commands

RHEL 6 -yum groupinstall
yum groupinfo

RHEL 7 – yum group install
yum group info

Default Inode Size

RHEL 6 – 256 bytes

[root@local ~]# tune2fs -l /dev/sda1|grep -i ‘inode size’

Inode size: 128

RHEL 7 – 512 bytes

[root@managed1 ]# xfs_info /dev/sda1|grep isize

meta-data=/dev/sda1 isize=512 agcount=4, agsize=65536 blks

Resizing an Lvm

RHEL 6 – EXT family of file systems could be resized if built on a logical volume as a block device.

RHEL 7 – As with XFS file system, resize is not possible.

TUNE A FILE SYSTEM

RHEL6: tune2fs

RHEL7: xfs_admin

IPTABLES AND FIREWALL

RHEL6: iptables

RHEL7: firewalld

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

COMMUNICATION BETWEEN TCP AND UDP IN BACK END

RHEL6: netcat

RHEL7: ncat

INTERFACE NAME

RHEL6: eth0

RHEL7: ens198(N)

COMBINING NIC

RHEL6: Network Bonding

RHEL7: Team Driver

NSF Server Version

RHEL6:  NFSv2

RHEL7:  NFSV4

DATABASE USED

RHEL6: Mysql

RHEL7: mariaDB

RHEL7 also support Mysql

MANAGING SERVICES

RHEL6:

#service sshd restart

#chkconfig sshd on

RHEL7:

#systemctl restart sshd

#systemctl enable shhd

File System.

RHEL6 default file system is ext4

xfs is RHEL7 default file system.

Kernel Version

RHEL6 default kernel version is 2.6 while RHEL7 is 3.10

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.

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.

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.

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)

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.

.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.

hostnamectl

nmtui

nmcli

Example:

in RHEL6              #hostname

in RHEL7              #hostnamectl  status   and #hostname

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