We had attempted a dual boot vps on KVM based vps
The os were installed using ISO
First to start with windows and then linux
However after installing linux the windows OS went missing
ON googling around found a solution
The issue was due to missing modules where we had to install module ntfs-3g
[root@ohours ~]# yum install ntfs-3g
 Loaded plugins: fastestmirror
 base                          
 extras                        
 updates                       
 (1/4): base/7/x86_64/group_gz        
 (2/4): extras/7/x86_64/primary_db    
 (3/4): updates/7/x86_64/primary_db   
 (4/4): base/7/x86_64/primary_db      
 Determining fastest mirrors
 * base: centos.mirror.lstn.net
 * extras: centos.mirror.lstn.net
 * updates: centos.mirror.lstn.net
 No package ntfs-3g available.
 Error: Nothing to do
we had to use epel repository to install ntfs-3g as its not available with normal repository
#Command to enable epel repository
[root@ohours ~]# yum install epel-release
 Loaded plugins: fastestmirror
 Loading mirror speeds from cached hostfile
 * base: centos.mirror.lstn.net
 * extras: centos.mirror.lstn.net
 * updates: centos.mirror.lstn.net
 Resolving Dependencies
 –> Running transaction check
 —> Package epel-release.noarch 0:7-9 will be installed
 –> Finished Dependency Resolution
Dependencies Resolved
==============================
 Package                      
 ==============================
 Installing:
 epel-release                 
Transaction Summary
 ==============================
 Install  1 Package
Total download size: 14 k
 Installed size: 24 k
 Is this ok [y/d/N]: y
 Downloading packages:
 warning: /var/cache/yum/x86_64/7/
 Public key for epel-release-7-9.noarch.rpm is not installed
 epel-release-7-9.noarch.rpm   
 Retrieving key from file:///etc/pki/rpm-gpg/RPM-
 Importing GPG key 0xF4A80EB5:
 Userid     : “CentOS-7 Key (CentOS 7 Official Signing Key) <security@centos.org>”
 Fingerprint: 6341 ab27 53d7 8a78 a7c2 7bb1 24c6 a8a7 f4a8 0eb5
 Package    : centos-release-7-4.1708.el7.
 From       : /etc/pki/rpm-gpg/RPM-GPG-KEY-
 Is this ok [y/N]: y
 Running transaction check
 Running transaction test
 Transaction test succeeded
 Running transaction
 Installing : epel-release-7-9.noarch       
 Verifying  : epel-release-7-9.noarch       
Installed:
 epel-release.noarch 0:7-9                         
Complete!
[root@ohours ~]# yum install ntfs-3g
 Loaded plugins: fastestmirror
 epel/x86_64/metalink          
 epel                          
 (1/3): epel/x86_64/group_gz          
 (2/3): epel/x86_64/updateinfo        
 (3/3): epel/x86_64/primary_db        
 Loading mirror speeds from cached hostfile
 * base: centos.mirror.lstn.net
 * epel: mirror.oss.ou.edu
 * extras: centos.mirror.lstn.net
 * updates: centos.mirror.lstn.net
 Resolving Dependencies
 –> Running transaction check
 —> Package ntfs-3g.x86_64 2:2017.3.23-1.el7 will be installed
 –> Finished Dependency Resolution
Dependencies Resolved
==============================
 Package                      
 ==============================
 Installing:
 ntfs-3g                      
Transaction Summary
 ==============================
 Install  1 Package
Total download size: 263 k
 Installed size: 612 k
 Is this ok [y/d/N]: y
 Downloading packages:
 warning: /var/cache/yum/x86_64/7/epel/
 Public key for ntfs-3g-2017.3.23-1.el7.x86_
 ntfs-3g-2017.3.23-1.el7.x86_
 Retrieving key from file:///etc/pki/rpm-gpg/RPM-
 Importing GPG key 0x352C64E5:
 Userid     : “Fedora EPEL (7) <epel@fedoraproject.org>”
 Fingerprint: 91e9 7d7c 4a5e 96f1 7f3e 888f 6a2f aea2 352c 64e5
 Package    : epel-release-7-9.noarch (@extras)
 From       : /etc/pki/rpm-gpg/RPM-GPG-KEY-
 Is this ok [y/N]: y
 Running transaction check
 Running transaction test
 Transaction test succeeded
 Running transaction
 Installing : 2:ntfs-3g-2017.3.23-1.el7.x86_
 Verifying  : 2:ntfs-3g-2017.3.23-1.el7.x86_
Installed:
 ntfs-3g.x86_64 2:2017.3.23-1.el7             
Complete!
#Using below command find the OS loaded in system
[root@ohours ~]# grub2-mkconfig > /dev/null
 Generating grub configuration file …
 Found linux image: /boot/vmlinuz-3.10.0-693.el7.
 Found initrd image: /boot/initramfs-3.10.0-693.
 Found linux image: /boot/vmlinuz-0-rescue-
 Found initrd image: /boot/initramfs-0-rescue-
 Found Windows Recovery Environment (loader) on /dev/sda1
 done
if windows is not found the OS may have got formatted while installing other OS
However our windows os was intact as the results show
#make backup copy of grub.conf
sudo cp /boot/grub2/grub.cfg /boot/grub2/grub.cfg.old
#Recreate the grub.conf to load windows and linux os using below command
sudo grub2-mkconfig -o /boot/grub2/grub.cfg
and now reboot and see both OS load
 



