{"id":6147,"date":"2016-08-07T15:15:07","date_gmt":"2016-08-07T07:15:07","guid":{"rendered":"http:\/\/rmohan.com\/?p=6147"},"modified":"2016-08-07T15:15:07","modified_gmt":"2016-08-07T07:15:07","slug":"rhel7-and-6-difference","status":"publish","type":"post","link":"https:\/\/mohan.sg\/?p=6147","title":{"rendered":"RHEL7 and 6 difference"},"content":{"rendered":"\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Features<\/td>\nRHEL 7<\/td>\nRHEL 6<\/td>\n<\/tr>\n
Default File System<\/td>\nXFS<\/td>\nEXT4<\/td>\n<\/tr>\n
Kernel Version<\/td>\n3.10.x-x kernel<\/td>\n2.6.x-x Kernel<\/td>\n<\/tr>\n
Kernel Code Name<\/td>\nMaipo<\/td>\nSantiago<\/td>\n<\/tr>\n
General Availability Date of First Major Release<\/td>\n2014-06-09 (Kernel Version 3.10.0-123)<\/td>\n2010-11-09 (Kernel Version 2.6.32-71)<\/td>\n<\/tr>\n
First Process<\/td>\nsystemd (process ID 1)<\/td>\ninit (process ID 1)<\/td>\n<\/tr>\n
Runlevel<\/td>\nrunlevels are called as “targets” as shown below:<\/p>\n

runlevel0.target -> poweroff.target
\nrunlevel1.target -> rescue.target
\nrunlevel2.target -> multi-user.target
\nrunlevel3.target -> multi-user.target
\nrunlevel4.target -> multi-user.target
\nrunlevel5.target -> graphical.target
\nrunlevel6.target -> reboot.target<\/p>\n

\/etc\/systemd\/system\/default.target (this by default is linked to the multi-user target)<\/td>\n

Traditional runlevels defined :<\/p>\n

runlevel 0
\nrunlevel 1
\nrunlevel 2
\nrunlevel 3
\nrunlevel 4
\nrunlevel 5
\nrunlevel 6<\/p>\n

and the default runlevel would be defined in \/etc\/inittab file.
\n\/etc\/inittab<\/td>\n<\/tr>\n

Host Name Change<\/td>\nIn Red Hat Enterprise Linux 7, as part of the move to the new init system (systemd), the hostname variable is defined in \/etc\/hostname.<\/td>\nIn Red Hat Enterprise Linux 6, the hostname variable was defined in the \/etc\/sysconfig\/network configuration file.<\/td>\n<\/tr>\n
Change In UID Allocation<\/td>\nBy default any new users created would get UIDs assigned starting from 1000.<\/p>\n

This could be changed in \/etc\/login.defs if required.<\/td>\n

Default UID assigned to users would start from 500.<\/p>\n

This could be changed in \/etc\/login.defs if required.<\/td>\n<\/tr>\n

Max Supported File Size<\/td>\nMaximum (individual) file size = 500TB
\nMaximum filesystem size = 500TB<\/p>\n

(This maximum file size is only on 64-bit machines. Red Hat Enterprise Linux does not support XFS on 32-bit machines.)<\/td>\n

Maximum (individual) file size = 16TB
\nMaximum filesystem size = 16TB<\/p>\n

(This maximum file size is based on a 64-bit machine. On a 32-bit machine, the maximum files size is 8TB.)<\/td>\n<\/tr>\n

File System Check<\/td>\n“xfs_repair”<\/p>\n

XFS does not run a file system check at boot time.<\/td>\n

“e2fsck”<\/p>\n

File system check would gets executed at boot time.<\/td>\n<\/tr>\n

Differences Between xfs_repair & e2fsck<\/td>\n\n“xfs_repair”<\/p>\n

– Inode and inode blockmap (addressing) checks.
\n– Inode allocation map checks.
\n– Inode size checks.
\n– Directory checks.
\n– Pathname checks.
\n– Link count checks.
\n– Freemap checks.
\n– Super block checks.<\/td>\n

\n“e2fsck”<\/p>\n

– Inode, block, and size checks.<\/p>\n

– Directory structure checks.<\/p>\n

– Directory connectivity checks.<\/p>\n

– Reference count checks.<\/p>\n

– Group summary info checks.<\/td>\n<\/tr>\n

Difference Between xfs_growfs & resize2fs<\/td>\n“xfs_growfs”<\/p>\n

xfs_growfs takes mount point as arguments.<\/td>\n

“resize2fs”<\/p>\n

resize2fs takes logical volume name as arguments.<\/td>\n<\/tr>\n

Change In File System Structure<\/td>\n\/bin, \/sbin, \/lib, and \/lib64 are now nested under \/usr.<\/td>\n\/bin, \/sbin, \/lib, and \/lib64 are usually under \/<\/td>\n<\/tr>\n
Boot Loader<\/td>\nGRUB 2
\nSupports GPT, additional firmware types, including BIOS, EFI and OpenFirmwar. Ability to boot on various file systems (xfs, ext4, ntfs, hfs+, raid, etc)<\/td>\n		GRUB 0.97<\/td>\n<\/tr>\n
KDUMP<\/td>\nRHEL7 supports kdump on large memory based systems up to 3 TB<\/td>\nKdump doesn\u2019t work properly with large RAM based systems.<\/td>\n<\/tr>\n
System & Service Manager<\/td>\n“Systemd”<\/p>\n

systemd is a system and service manager for Linux, and replaces SysV and Upstart used in previous releases of Red Hat Enterprise Linux. systemd is compatible with SysV and Linux Standard Base init scripts.<\/td>\n

Upstart<\/td>\n<\/tr>\n
Enable\/Start Service<\/td>\nFor RHEL 7, the systemctl command replaces service and chkconfig.<\/p>\n

– Start Service : “systemctl start nfs-server.service”.<\/p>\n

– Enable Service : To enable the service (example: nfs service ) to start automatically on boot : “systemctl enable nfs-server.service”.<\/p>\n

Although one can still use the service and chkconfig commands to start\/stop and enable\/disable services, respectively, they
\nare not 100% compatible with the RHEL 7 systemctl command (according to redhat).<\/td>\n

Using “service” command and “chkconfig” commands.<\/p>\n

– Start Service : “service start nfs” OR “\/etc\/init.d\/nfs start”<\/p>\n

– Enable Service : To start with specific runlevel : “chkconfig –level 3 5 nfs on”<\/td>\n<\/tr>\n

Default Firewall<\/td>\n“Firewalld (Dynamic Firewall)”<\/p>\n

The built-in configuration is located under the \/usr\/lib\/firewalld directory. The configuration that you can customize is under the \/etc\/firewalld directory. It is not possible to use Firewalld and Iptables at the same time. But it is still possible to disable Firewalld and use Iptables as before.<\/td>\n

Iptables<\/td>\n<\/tr>\n
Network Bonding<\/td>\n“Team Driver”<\/p>\n

-\/etc\/sysconfig\/network-scripts\/ifcfg-team0
\n– DEVICE=\u201dteam0\u201d
\n– DEVICETYPE=\u201dTeam\u201d<\/td>\n

“Bonding”<\/p>\n

-\/etc\/sysconfig\/network-scripts\/ifcfg-bond0
\n– DEVICE=\u201dbond0\u201d<\/td>\n<\/tr>\n

Network Time Synchronization<\/td>\nUsing Chrony suite (faster time sync compared with ntpd)<\/td>\nUsing ntpd<\/td>\n<\/tr>\n
NFS<\/td>\nNFS4.1
\nNFSv2 is no longer supported. Red Hat Enterprise Linux 7 supports NFSv3, NFSv4.0, and NVSv4.1 clients.<\/td>\n		NFS4<\/td>\n<\/tr>\n
Cluster Resource Manager<\/td>\nPacemaker<\/td>\nRgmanager<\/td>\n<\/tr>\n
Load Balancer Technology<\/td>\nKeepalived and HAProxy<\/td>\nPiranha<\/td>\n<\/tr>\n
Desktop\/GUI Interface<\/td>\nGNOME3 and KDE 4.10<\/td>\nGNOME2<\/td>\n<\/tr>\n
Default Database<\/td>\nMariaDB is the default implementation of MySQL in Red Hat Enterprise Linux 7<\/td>\nMySQL<\/td>\n<\/tr>\n
Managing Temporary Files<\/td>\nRHEL 7 uses systemd-tmpfiles (more structured, and configurable, method to manage tmp files and directories).<\/td>\nUsing “tmpwatch”<\/td>\n<\/tr>\n
<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"excerpt":{"rendered":"

Features RHEL 7 RHEL 6 Default File System XFS EXT4 Kernel Version 3.10.x-x kernel 2.6.x-x Kernel Kernel Code Name Maipo Santiago General Availability Date of First Major Release 2014-06-09 (Kernel Version 3.10.0-123) 2010-11-09 (Kernel Version 2.6.32-71) First Process systemd (process ID 1) init (process ID 1) Runlevel runlevels are called as “targets” as shown […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[73],"tags":[],"_links":{"self":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/6147"}],"collection":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=6147"}],"version-history":[{"count":1,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/6147\/revisions"}],"predecessor-version":[{"id":6148,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/6147\/revisions\/6148"}],"wp:attachment":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=6147"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=6147"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=6147"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}