Check current OS modules
# lsmod
Check modules detail info
# modinfo st
filename: /lib/modules/2.6.32-279.22.1.el6.x86_64/kernel/drivers/scsi/st.ko
alias: scsi:t-0x01*
alias: char-major-9-*
license: GPL
description: SCSI tape (st) driver
author: Kai Makisara
srcversion: 782F465A959216B1E70B888
depends:
vermagic: 2.6.32-279.22.1.el6.x86_64 SMP mod_unload modversions
parm: buffer_kbs:Default driver buffer size for fixed block mode (KB; 32) (int)
parm: max_sg_segs:Maximum number of scatter/gather segments to use (256) (int)
parm: try_direct_io:Try direct I/O between user buffer and tape drive (1) (int)
parm: try_rdio:Try direct read i/o when possible (int)
parm: try_wdio:Try direct write i/o when possible (int)
# modinfo -p st #Only check module st paremeters
try_wdio:Try direct write i/o when possible
try_rdio:Try direct read i/o when possible
try_direct_io:Try direct I/O between user buffer and tape drive (1)
max_sg_segs:Maximum number of scatter/gather segments to use (256)
buffer_kbs:Default driver buffer size for fixed block mode (KB; 32)
Load module
# lsmod |grep st
stp 2173 1 garp
llc 5546 2 garp,stp
# modprobe st
# lsmod |grep st
st 38302 0
stp 2173 1 garp
llc 5546 2 garp,stp
Unload module
# rmmod st
# lsmod |grep st
stp 2173 1 garp
llc 5546 2 garp,stp
Set default modules parameters
1. Check module's default parameter value
a. Load modules
# modprobe usb_storage
# modprobe st
# modprobe sx8
b. Get module's parameter info
# modinfo -p usb_storage
quirks:supplemental list of device IDs and their quirks
delay_use:seconds to delay before using a new device
swi_tru_install:TRU-Install mode (1=Full Logic (def), 2=Force CD-Rom, 3=Force Modem)
option_zero_cd:ZeroCD mode (1=Force Modem (default), 2=Allow CD-Rom
# modinfo -p st
try_wdio:Try direct write i/o when possible
try_rdio:Try direct read i/o when possible
try_direct_io:Try direct I/O between user buffer and tape drive (1)
max_sg_segs:Maximum number of scatter/gather segments to use (256)
buffer_kbs:Default driver buffer size for fixed block mode (KB; 32)
# modinfo -p sx8
max_queue:Maximum number of queued commands. (min==1, max==30, safe==1)
c. Check the default value
# cat /sys/module/usb_storage/parameters/delay_use
1
# cat /sys/module/sx8/parameters/max_queue
1
2. Modify the default value
a. Set parameter value
# cat /etc/modprobe.d/my.conf
options usb_storage delay_use=3
options sx8 max_queue=15
options st buffer_kbs=256
b. Reload modules
# rmmod st
# rmmod sx8
# rmmod usb_storage
# modprobe st
# modprobe sx8
# modprobe usb_storage
c. Check you changed value
# cat /sys/module/usb_storage/parameters/delay_use
3
# cat /sys/module/sx8/parameters/max_queue
15
3. Set module auto-start with modified parameter
系统是如何自动加载模块呢，我们在/etc/rc.sysinit启动文件中看到下面内容。在系统启动过程中会自动的执行/etc/sysconfig/modules/下所有以.modules结尾的文件。那么我们也可以在该目录下编写自定义的脚本，在配合/etc/modprobe.d/my.conf设置的参数，就可以实现我们设置的参数开机自启动了。
# Load other user-defined modules
for file in /etc/sysconfig/modules/*.modules ; do
[ -x $file ] && $file
done
a. Create self-definition script
# cat /etc/sysconfig/modules/my.modules
modprobe st
modprobe sx8
modprobe usb_storage
b. Do not forget add execute permission
# chmod a+x /etc/sysconfig/modules/my.modules
# ls -l /etc/sysconfig/modules/my.modules
-rwxr-xr-x 1 root root 46 Aug 22 09:09 /etc/sysconfig/modules/my.modules
4. Disable ipv6 module on RHEL/CentOS 5.
Modify below to files.
/etc/modprobe.conf - Kernel driver configuration file.
/etc/sysconfig/network - RHEL / CentOS networking configuration file.
a. Edit /etc/modprobe.conf, and append the following line:
# vi /etc/modprobe.conf
install ipv6 /bin/true
b. Edit /etc/sysconfig/network, and update / add as follows:
# vi /etc/sysconfig/network
NETWORKING_IPV6=no
IPV6INIT=no
IPV6INIT=no
c. Restart network service.
# service network restart
# rmmod ipv6
Alternatively, simple reboot the box:
# reboot
d. Verify IPv6 is disabled, enter:
# lsmod | grep ipv6
# /sbin/ifconfig
5. Disable ipv6 module on RHEL/CentOS 6.
a.Edit /etc/sysconfig/network, and update / add as follows:
NETWORKING_IPV6=no
b. Modify file /etc/hosts, and comment out below line：
#::1 localhost localhost6 localhost6.localdomain6
c. Restart network service.
# service network restart
# rmmod ipv6
d. Disable auto enable across OS reboot. And below contents in file /etc/modprobe.d/ipv6off.conf.
alias net-pf-10 off
options ipv6 disable=1