OS Version Research

1 Introduction 1.1 Purpose of writing

The main purpose of this article is to compare the various versions of the operating system used in the current project, analyze their characteristics and stability, and ultimately recommend the appropriate version as the current standard system.

1.2 Background

At present, the department is responsible for the management and maintenance of the current network using a wide range of operating systems, mainly related to CentOS, SLES, Ubuntu, RHEL, Windows and so on; Because of the different operating system sizes, increased management costs and inconvenience to maintenance, a unified standard is needed.

1.3 References

No

2 Usage Analysis 2.1 Usage overview

Online version	Usage rate
CentOS (5.4/5.8/6.4/6.5/6.6/7)	Low (5 series), High (6/7 series)
Sles11sp3	Low
Windows (2003/2008/2012)	Low
Ubuntu14	Low
RHEL (5.4/5.8/6.5)	Low

Table 1

2.2 Common system Analysis

From the statistical results, the use of more is the CENTOS6/7 system, the current standard system selection will be selected from the CentOS. CentOS is the abbreviation of Community Enterprise Operating system, called Community business operating system, which is a distribution version of Linux. CentOS is not a new Linux distribution, it is a cloned version of Red Hat Enterprise Linux (hereafter known as Rhel), and Rhel is a Linux distribution used by many enterprises and needs to be paid to Redhat for use. And can get paid users of service and technical support and version upgrade. This CentOS can build Linux system environment like Rehl, but do not need to pay redhat any fees, also get no paid technical support and upgrade service.

3 Feature Analysis

The CENTOS6/7 series versions currently in use are analyzed to select the benchmark OS.

Release	Official release	Last Updated
6.5	2013-12-01	2014-02-26
6.6	2014-10-27	2014-11-15
6.7	2015-08-07	2015-08-15
7.0	2014-07-07	2015-10-11
7.1	2015-04-01	2015-10-11

Table 2

3.1 Major changes

OS Version	Changes
6.5	Precision Time Protocol--The original Technology preview--has now been fully supported. The following drivers support network time stamping: bnx2x, TG3, e1000e, IGB, Ixgbe, and SFC. OpenSSL has been updated to version 1.0.1. OpenSSL and NSS now support TLS 1.1 and 1.2. Several improvements have been added to KVM, including improved read-only support for VMDK and VHDX files, CPU hot-plugging, and updated virt-v2v-/virt-p2v-conversion tools. Hyper-V and VMware drivers have been updated. Update Evolution (2.32) and Libre Office (4.0.4).
6.6	Enhanced handling of SCSI devices helps to cope with certain directives. The Openvswitch module is now a kernel module. The new HyperV long-standing program helps CentOS run on the Microsoft HyperV host. As a technology preview, 6.6 can run as a second-generation VM on Microsoft's 2012R2 Hyperv. Full support for keepalived and Haproxyd Support for the new Intel Wildcat Platform Added OpenJDK as a tech preview.
6.7	SSSD has a number of new features Support for forcing the removable media to be mounted in read-only mode with UDEV rules for enhanced security Full support for LVM high-speed buffering New Clufter components to analyze and convert the cluster configuration file format Default disable SSLV3 and older unsafe protocols, and different components also add more options to the Protocol settings Vim has been switched to version 7.4, which improves cancellation and formal expression LibreOffice has been upgraded to 4.2.8.2 KVM Supervisor can now manage 240 virtual processors for each virtualized machine Allow IPV6 IP clusters to be used within firewall rules Squid has been replaced with 3.1.23 version and supports http/1.1 post and put response without a principal Mdadm has been used in version 3.3.2 to improve support for migrating RAID levels and auto-rebuilding arrays The Yum-plugin-downloadonly component has been replaced by the main Yum component because the feature has been integrated
7.0	Kernel update to 3.10.0 Support for Linux containers Open VMware Tools and 3D images are ready to use OpenJDK-7 as Default JDK In-situ upgrade 6.5 to 7.0 (mentioned above) LVM snapshots for Ext4 and XFS Switch to Systemd, FIREWALLD and GRUB2 XFS as Default file system ISCSI and FCoE within the kernel space Support PTPv2 Supports 40G Ethernet network card
7.1	From March 2015 onwards, ABRT (>= 2.1.11-19.el7.centos.0.1) can report bugs directly to bugs.centos.org, where you can find more information about this feature. Support for new processors (Broadwell) and image cards (AMD Hawaii) Full support for LVM caching Can mount Ceph block devices Update the Hyper-V network Driver The new LIBGUESTFS feature Full support openJDK-1.8.0 Improved stability of clocks (PTP and NTP) Update Networkmanager components to version 1.0 Update Docker to 1.4.1 Update OpenSSH to 6.6.1 New component: Mozilla Thunderbird Update multiple storage, network, and image card drivers Tech preview: Support for Btrfs file system, OVERLAYFS, and Cisco VIC kernel drivers

Table 3

3.2 Downgrade function

OS Version	Downgrade feature
6.5	As announced at the 6.4 release, Matahari has been downgraded and is no longer included in the 6.5. The following components have been degraded and are likely to be removed in future releases. They will no longer be updated: mingw-gcc Mingw-boost Mingw32-qpid-cpp Python-qmf Python-qpid Qpid-cpp Qpid-qmf Qpid-tests Qpid-tools Ruby-qpid Saslwrapper
6.6	The following components have been degraded in CentOS 6.3 and have been removed from CentOS 6.6: mingw-gcc Mingw-boost Mingw32-qpid-cpp The following components have been downgraded and are likely to be deleted in future releases. They will no longer be updated: Python-qmf Python-qpid Qpid-cpp Qpid-qmf Qpid-tests Qpid-tools Ruby-qpid Saslwrapper
6.7	The following components have been downgraded and are likely to be deleted in future releases. They will no longer be updated: Python-qmf Python-qpid Qpid-cpp Qpid-qmf Qpid-tests Qpid-tools Ruby-qpid Saslwrapper
7.0	No
7.1	i686 versions of the following components: Krb5-server and Krb5-server-ldap Further components to be discarded: LIBVIRT-DAEMON-DRIVER-LXC, LIBVIRT-DAEMON-LXC and Libvirt-login-shell

Table 4

3.3 Known Issues

OS Version	Known Issues
6.5	The upstream Mozilla NSS has stopped supporting the MD5-signed voucher from version 3.14, which has been added to CentOS 6.4. Details and expediency can be found within this Fedora Bugzilla report. As far as Intel and AMD processor architectures are concerned, CentOS 6 mimics upstream requirements, requiring that the 32-bit x86 chip must support PAE. The installer requires at least 406MB of memory to function. Text mode is automatically applied to systems with less than 632MB of memory. The function of the text installation is limited compared to the image installation program. Insufficient memory to configure kdump! This message will appear at the time of installation. This known problem occurs on systems with less than 2GB of memory. You don't have to ignore it. The contents of the i386 and x86_64 structures are divided into two DVDs. We try to make all basic servers and basic desktop installations only need to be DVD-1. When you turn the public key to a SELinux-enabled CentOS 6 server, make sure it has the correct selinux context. Otherwise, SELinux may refuse access to the ~/.ssh/authorized_keys, which in turn will invalidate the key verification. The entire X86_64 installation ISO and minimal ISO can be booted on EFI hardware. There are several components with a name of. CentOS. The wording has not been modified, see CentOS error #0005281 for details. The following are the SRPM that are still affected within 6.5: At-spi Gtk2-engines Libcanberra Libgail-gnome Libwmf For older AMD (formerly ATI) display cards, the official drivers for the 2xxx, 3XXX, and 4XXX series are not compatible with the new X server introduced by CentOS-6.4. By the middle of 20,133 months, the only expedient to support the official driver was to downgrade the X server (xorg* component) to the version provided by CentOS 6.3. To prevent Yum from re-upgrading your degraded components, add the following to the/etc/yum.conf's end exclude=xorg*. Please note that if you only want to set up dual monitors under CENTOS-6, you do not need an official driver. VMware workstation pairing (included with CentOS-6.5) Glib2-2.26.1-3 and kernel-2.6.32-431, there is a problem when you execute Microsoft Windows.
6.6	Note: OpenSSL contained within the installation media contains poodle vulnerabilities. Regardless of which installation media you use, perform Yum update after installation to obtain CentOS-6.6 security updates. The netinstall ISO file cannot be installed with UEFI, but the minimal or DVD ISO file can be combined with UEFI. No version of CentOS-6.6 can operate after Secure Boot is enabled. You must deactivate Secure Boot to install CentOS-6.6. The ABI of the X.Org display driver from this release is subject to change and may cause x-session to fail. As far as Intel and AMD's processor architectures are concerned, CentOS 6 mimics upstream requirements, requiring the 32-bit x86 chip to support PAE. The installer requires up to 406MB of memory to function. Text mode is automatically applied to systems with less than 632MB of memory. The function of the text installation is limited compared to the image installation program. Insufficient memory to configure kdump! This message will appear at the time of installation. This known problem occurs on systems with less than 2GB of memory. You don't have to ignore it. The contents of the i386 and x86_64 structures are divided into two DVDs. We try to make all basic servers and basic desktop installations only need to be DVD-1. When you turn the public key to a SELinux-enabled CentOS 6 server, make sure it has the correct selinux context. Otherwise, SELinux may refuse access to the ~/.ssh/authorized_keys, which in turn will invalidate the key verification. There are several components with a name of. CentOS. Words have not been modified. The following are the SRPM that are still affected within 6.6: At-spi Gtk2-engines Libcanberra Libgail-gnome There are two changes in the way the IPA is installed: When the password expires, Kinit will ask for a new password, it will not grant a new subpoena, and you will need a kinit with a new password. When you install the client of the IPA (including the guest that is automatically installed on the server), sudo is now automatically set and you do not need to modify sssd.conf and nsswitch.conf.
6.7	On UEFI-enabled systems, the CentOS 6.x writes the boot settings to/boot/efi/efi/redhat. This poses a problem for those who intend to install CentOS and RHEL on the same system. This problem will not be solved during the life cycle of CentOS 6. CentOS 7 does not have this problem. VirtualBox a problem may occur when opening a CentOS 6 virtual machine created in UEFI mode. The boost-1.41.0-27.el6 provided by CentOS 6.7 may cause problems in compiling some components. See upstream error #1245805 for details. If you encounter this problem, we recommend that you update the components with CentOS 6.6 Boost-1.41.0-25.el6.centos until the problem is resolved. The Satyr component provided by EPEL (which has been removed due to a conflict with RHEL 6.7) is newer than the CentOS 6.7 version. The components provided by EPEL seem to work correctly. We have not found any negative impact on this issue. If you have installed the Satyr component from EPEL, but are interested in switching to the CentOS version, please perform the Yum downgrade Satyr. The EPEL provides an older json-c component than the CentOS 6.7 version. If you installed a json-c from EPEL to avoid yum problems, please update the system to 6.7 after uninstalling the component. The Sssd-common on CentOS 6.7 no longer provides multilib. If you have a 32-bit Sssd-common installed on the x86_64 system, you must perform the Yum remove sssd-common.i686 before the update to remove it. Netinstall images cannot be installed in Uefi, but minimal or DVD images can be combined with UEFI. CentOS-6.7 No version can function after Secure Boot is enabled. You must deactivate Secure Boot to install CentOS-6.7. (See CentOS error #6321 for details). As far as Intel and AMD's processor architectures are concerned, CentOS 6 mimics upstream requirements, requiring the 32-bit x86 chip to support PAE. The installer requires at least 406MB of memory to function. Text mode is automatically applied to systems with less than 632MB of memory. The function of the text installation is limited compared to the image installation program. Insufficient memory to configure kdump! This message will appear at the time of installation. This known problem occurs on systems with less than 2GB of memory. You don't have to ignore it. The contents of the i386 and x86_64 structures are divided into two DVDs. We try to make all basic servers and basic desktop installations only need to be DVD-1. When you turn the public key to a SELinux-enabled CentOS 6 server, make sure it has the correct selinux context. Otherwise, SELinux may refuse access to the ~/.ssh/authorized_keys, which in turn will invalidate the key verification. You can set up the correct SELinux context: Restorecon-r-v/home/$ACCOUNT/.ssh There are several components with a name of. CentOS. The wording has not been modified, see CentOS error #5281 for details. The following are the SRPM that are still affected within 6.7: At-spi Gtk2-engines Libcanberra Libgail-gnome Tigervnc has a. CentOS in the component name. Because it is rebuilt by relying on new components. The component itself is unaltered. Please refer to the CentOS error #7804.
7.0	Many users complain that the new default NetworkManager tool does not enable the Ethernet interface and must be manually enabled for installation. The installer requires a minimum of 406MB of memory to run. On systems with less than 406MB, the installer terminates abnormally. The minimum memory requirement for C7 is 512MB. The CentOS-7 is not properly installed on a VirtualBox virtual machine via UEFI mode on the Encrypting File System. Unless you modify the command line of the kernel, the system will not ask for a sector password after installation. See the error report for details. If your image is 800x600 or lower, the lower end of the installation screen will be cut off.
7.1	The Minimal image only supports minimal installation, even though the installer lists other options. You can install additional components after the installation is complete, or use other installation images to choose the options you want. If you use Dell OpenManage 7.4.1 or 8.1.0.,omreport storage vdisk and some sub-directives may not display the required information. This problem also appears to occur in RHEL 7.1. OMSA 8.1.0, along with a slightly modified Libstorelib file, appears to be available. Do systemctl restart Dataeng.service after you follow the instructions to modify the file. The kernel kernel 3.10.0-229.7.2 has reintroduced the required Release_date driver properties, so OMSA files are no longer modified. LIBREOFFICE Spreadsheet Component Calc introduces an error that affects the sorting function of the spreadsheet. Please see the error report here and here. The new version of OpenSSH in this release will not be left without the first pairing found in the. ssh/config file as in the previous release. This means that when a configuration file has more than one host part paired with one of the hosts, they all get na. For example: If you have both host1.example.com settings and *.example.com settings, both sets will be applied to host1.example.com, but only *.example.com will be applied to the Host2.example.com. Many users complain that the new default NetworkManager tool does not enable the Ethernet interface and must be manually enabled for installation. See CentOS-7 FAQ #2. The installer requires a minimum of 406MB of memory to run. On systems with less than 406MB, the installer terminates abnormally. The minimum memory requirement for CentOS-7 is 512MB. The CentOS-7 is not properly installed on a VirtualBox virtual machine via UEFI mode on the Encrypting File System. Unless you modify the command line of the kernel, the system will not ask for a sector password after installation. See the error report for details. If your image is 800x600 or lower, the lower end of the installation screen will be cut off. VMware Workstation/vmware ESXi allows you to install two different virtual SCSI adapters: BusLogic and Lsilogic. However, the default kernel of CentOS-7 does not contain the corresponding two drivers, so the default value of CentOS Linux is installed on the SCSI hard drive and the system will not boot. If you choose Red Hat Enterprise Linux as your operating system, it will select the applicable para-virtualized SCSI adapter. Common tools such as ifconfig/netstat have been labeled degraded for some time, and the Net-tools component is no longer included in the @core group, so it is not installed by default. If you really need it, please use NMCLI c UP ifname < interface name > enable your network and install the component via Yum. Kickstart users can add net-tools this component at the time of installation. ALPSPS/2 ALPS dualpoint TouchPad in the CentOS-7 of the lack of saving can not use edge rolling. See error 7403 for instructions on enabling this feature. As of VirtualBox 4.3.12 version, VBox additions cannot be created. This issue has been resolved since version 4.3.14. As of 4.3.16,windows the host still seems to be having problems. After installing VBox additions, log on to the GNOME desktop with a black screen or terminate the virtual machine.

Table 5

4 Summary 4.1 Research results

Up to now, CentOS and upstream Rhel has a number of problems statistics 1/2, of which 6 series involves 8 versions, 7 Series involves 2 versions, data for reference only, not as a Judge 6, 7 merits.

Overall, Rhel found that the number of problems is centos5~10 times, this is because Rhel as upstream and widely used, the problem is easy to find first, CentOS will be updated, the number of problems will converge.

Figure 1 RHEL BUG

Figure 2 CentOS BUG

4.2 Conclusion

1. Selection principle: The production system needs to use a stable version; The industry typically does not use the latest version and takes precedence over the previous version.

2. Overall, the new release in 2015, CentOS6.7, 7.1, a period of time to stabilize, the proposal is not considered, CentOS6.5, 6.6 are more stable, 6.6 optimized hyperv support and full support ha, given that the subsequent business will rely more on virtualization, It is recommended that the 6.6 release be prioritized; CentOS7.0 because of the large version of the upgrade, there are many new features also bring some instability factors, it is recommended that the core system continue to use 6.6, non-core business can try to use 7.0.

3. From a maintenance perspective, standardization reduces management costs, increases efficiency, and makes it necessary to develop unified OS standards.

OS Version Research