[root@client ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sr0 11:0 1 1024M 0 rom
sda 8:0 0 10G 0 disk
├─sda1 8:1 0 500M 0 part /boot
└─sda2 8:2 0 9.5G 0 part
├─VolGroup-lv_root (dm-0) 253:0 0 8.5G 0 lvm /
└─VolGroup-lv_swap (dm-1) 253:1 0 1G 0 lvm [SWAP]
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sr0 11:0 1 1024M 0 rom
sda 8:0 0 10G 0 disk
├─sda1 8:1 0 500M 0 part /boot
└─sda2 8:2 0 9.5G 0 part
├─VolGroup-lv_root (dm-0) 253:0 0 8.5G 0 lvm /
└─VolGroup-lv_swap (dm-1) 253:1 0 1G 0 lvm [SWAP]
[root@client ~]# dd if=/dev/zero of=/dev/sda bs=1 count=446
446+0 records in
446+0 records out
446 bytes (446 B) copied, 0.0100412 s, 44.4 kB/s
446+0 records in
446+0 records out
446 bytes (446 B) copied, 0.0100412 s, 44.4 kB/s
[root@client ~]# init 6[root@client ~]# Connection to 192.168.122.199 closed by remote host.
Connection to 192.168.122.199 closed.
Connection to 192.168.122.199 closed.
By above command i will corrupt grub
Once i reboot u can see the effect of above command
Select No In above screen
[root@localhost ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 10G 0 disk
├─sda1 8:1 0 300M 0 part /boot
├─sda2 8:2 0 8.7G 0 part /
└─sda3 8:3 0 1G 0 part [SWAP]
sr0 11:0 1 3.6G 0 rom /media/CentOS_6.7_Final
Installing GRUB using grub-install
go to linux rescue mode then.to reinstall grub.conf follow this one of the method..
1)check that grub.conf exists r not.
check in the cmd pmt about older kernel version,then install same kernel and enjoy…then automatically you will get grub.confif not then install grub by this method;
if it has server with nfs image then select user mode 1
for eg:
chroot /mnt/sysimage
grub install /dev/sda
exit
then type grub
grub> root (hd0,0)
grub> setup (hd0)
quit
restart
1)check that grub.conf exists r not.
check in the cmd pmt about older kernel version,then install same kernel and enjoy…then automatically you will get grub.confif not then install grub by this method;
if it has server with nfs image then select user mode 1
for eg:
chroot /mnt/sysimage
grub install /dev/sda
exit
then type grub
grub> root (hd0,0)
grub> setup (hd0)
quit
restart
linuxmadeeasy 