Specifying Kernel Boot Parameters
KERNEL (OS AND HARDWARE)Kernel
is a heart of the OS. It manage communication with hardware ,device
which to run, and provide each process with an oslated, virtual address
space in which to run the kernel loads device drive modules. It also
allocate hardware resources such as IRQ ports I/O address and DMA
channels.
TYPES OF KERNELMONOLITHIC VERSUS MODULAR. { WINDOWS}A monolithic kernel is a kernel in which all the devices module are built directory in to the kernel .Monolithic kernel can communicate with devices faster.
MODULAR KERNELS {LINUX}
Modular kernel have many of their devices built as separate loadable modules .
How we configure a system when it boot it should automatically get "max_loop 32" and when we run
"cat /proc/cmdline" it must show "max_loop=32"
The loopback device is used to mount files as if they were devices, which is very convenient for accessing ISO images, for
example. By default, the kernel supports 8 loopback devices. Modify your remote server's kernel command line so that 32
are supported instead.
Check default loop device status
# ls /dev/loop*
/dev/loop0 /dev/loop2 /dev/loop4 /dev/loop6
/dev/loop1 /dev/loop3 /dev/loop5 /dev/loop7
Add the parameter max_loop=32 to the kernel command line in /boot/grub/grub.conf
root@server1 Desktop]# vim /boot/grub/grub.conf
# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE: You have a /boot partition. This means that
# all kernel and initrd paths are relative to /boot/, eg.
# root (hd0,0)
# kernel /vmlinuzversion ro root=/dev/sda2
# initrd /initrd[generic]version.img
#boot=/dev/sda
default=0
timeout=5
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title Red Hat Enterprise Linux (2.6.32220.el6.x86_64)
root (hd0,0)
kernel /vmlinuz2.6.32220.el6.x86_64 ro root=UUID=8c2fa6d5b99b4a0b940f37219d255df7 rd_NO_LUKS
rd_NO_LVM LANG=en_US.UTF8 rd_NO_MD quiet SYSFONT=latarcyrhebsun16 rhgb crashkernel=auto KEYBOARDTYPE=pc
KEYTABLE=us rd_NO_DM max_loop=32
initrd /initramfs2.6.32220.el6.x86_64.img
# cat /proc/cmdline
ro root=UUID=8c2fa6d5b99b4a0b940f37219d255df7 rd_NO_LUKS rd_NO_LVM LANG=en_US.UTF8 rd_NO_MD quiet
SYSFONT=latarcyrhebsun16 rhgb KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM max_loop=32
# ls /dev/loop*
/dev/loop0 /dev/loop14 /dev/loop2 /dev/loop25 /dev/loop30 /dev/loop8
/dev/loop1 /dev/loop15 /dev/loop20 /dev/loop26 /dev/loop31 /dev/loop9
/dev/loop10 /dev/loop16 /dev/loop21 /dev/loop27 /dev/loop4
/dev/loop11 /dev/loop17 /dev/loop22 /dev/loop28 /dev/loop5
/dev/loop12 /dev/loop18 /dev/loop23 /dev/loop29 /dev/loop6
/dev/loop13 /dev/loop19 /dev/loop24 /dev/loop3 /dev/loop7
TYPES OF KERNELMONOLITHIC VERSUS MODULAR. { WINDOWS}A monolithic kernel is a kernel in which all the devices module are built directory in to the kernel .Monolithic kernel can communicate with devices faster.
MODULAR KERNELS {LINUX}
Modular kernel have many of their devices built as separate loadable modules .
How we configure a system when it boot it should automatically get "max_loop 32" and when we run
"cat /proc/cmdline" it must show "max_loop=32"
The loopback device is used to mount files as if they were devices, which is very convenient for accessing ISO images, for
example. By default, the kernel supports 8 loopback devices. Modify your remote server's kernel command line so that 32
are supported instead.
Check default loop device status
# ls /dev/loop*
/dev/loop0 /dev/loop2 /dev/loop4 /dev/loop6
/dev/loop1 /dev/loop3 /dev/loop5 /dev/loop7
Add the parameter max_loop=32 to the kernel command line in /boot/grub/grub.conf
root@server1 Desktop]# vim /boot/grub/grub.conf
# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE: You have a /boot partition. This means that
# all kernel and initrd paths are relative to /boot/, eg.
# root (hd0,0)
# kernel /vmlinuzversion ro root=/dev/sda2
# initrd /initrd[generic]version.img
#boot=/dev/sda
default=0
timeout=5
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title Red Hat Enterprise Linux (2.6.32220.el6.x86_64)
root (hd0,0)
kernel /vmlinuz2.6.32220.el6.x86_64 ro root=UUID=8c2fa6d5b99b4a0b940f37219d255df7 rd_NO_LUKS
rd_NO_LVM LANG=en_US.UTF8 rd_NO_MD quiet SYSFONT=latarcyrhebsun16 rhgb crashkernel=auto KEYBOARDTYPE=pc
KEYTABLE=us rd_NO_DM max_loop=32
initrd /initramfs2.6.32220.el6.x86_64.img
# cat /proc/cmdline
ro root=UUID=8c2fa6d5b99b4a0b940f37219d255df7 rd_NO_LUKS rd_NO_LVM LANG=en_US.UTF8 rd_NO_MD quiet
SYSFONT=latarcyrhebsun16 rhgb KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM max_loop=32
# ls /dev/loop*
/dev/loop0 /dev/loop14 /dev/loop2 /dev/loop25 /dev/loop30 /dev/loop8
/dev/loop1 /dev/loop15 /dev/loop20 /dev/loop26 /dev/loop31 /dev/loop9
/dev/loop10 /dev/loop16 /dev/loop21 /dev/loop27 /dev/loop4
/dev/loop11 /dev/loop17 /dev/loop22 /dev/loop28 /dev/loop5
/dev/loop12 /dev/loop18 /dev/loop23 /dev/loop29 /dev/loop6
/dev/loop13 /dev/loop19 /dev/loop24 /dev/loop3 /dev/loop7
How we configure a system when it boot it should automatically get "syslevel 9" and when we run
"cat /proc/cmdline" it must show "syslevel=9"
# cat /proc/cmdline
ro root=UUID=8c2fa6d5b99b4a0b940f37219d255df7 rd_NO_LUKS rd_NO_LVM LANG=en_US.UTF8 rd_NO_MD quiet
SYSFONT=latarcyrhebsun16 rhgb KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM
# vim /etc/grub.conf
# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE: You have a /boot partition. This means that
# all kernel and initrd paths are relative to /boot/, eg.
# root (hd0,0)
# kernel /vmlinuzversion ro root=/dev/sda2
# initrd /initrd[generic]version.img
#boot=/dev/sda
default=0
timeout=5
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title Red Hat Enterprise Linux (2.6.32220.el6.x86_64)
root (hd0,0)
kernel /vmlinuz2.6.32220.el6.x86_64 ro root=UUID=8c2fa6d5b99b4a0b940f37219d255df7 rd_NO_LUKS
rd_NO_LVM LANG=en_US.UTF8 rd_NO_MD quiet SYSFONT=latarcyrhebsun16 rhgb crashkernel=auto KEYBOARDTYPE=pc
KEYTABLE=us rd_NO_DM syslevel=9
initrd /initramfs2.6.32220.el6.x86_64.img
:wq!
# reboot
# cat /proc/cmdline
ro root=UUID=8c2fa6d5b99b4a0b940f37219d255df7 rd_NO_LUKS rd_NO_LVM LANG=en_US.UTF8 rd_NO_MD quiet
SYSFONT=latarcyrhebsun16 rhgb KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM syslevel=9
Note:
Above same steps using “kernbulb=1” and “sysvctl=1”
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