Friday, March 18, 2011

Disable (Block) CD/DVD ROM Linux ( RHEL )


Today i am going to  share,   how to block or disable CD/DVD ROM in Linux.
Please find the below procedure is working fine on RHEL ( Red Hat Enterprise Linux 5).

1) You need to be root user to perform steps.
[root@localhost]$  su -
2) Go to Directory Where your kernel drivers stored. Follow exact command.
[root@localhost]# cd /lib/modules/$(uname -r)/kernel/drivers/cdrom
3) Now list directory.
[root@localhost cdrom]# ls
cdrom.ko
4) Now rename or delete cdrom.ko file with following command.
[root@localhost cdrom]# mv cdrom.ko cdrom.ko-ok
To Delete file execute below command
[root@localhost cdrom]# rm -rf cdrom.ko
5) Now reboot your computer and Insert CD or DVD into Drive. It will not detect.
6) If you dont want to reboot your computer then just execute below command.
modprobe -r sr_mod

Hope this information helps you.

Tuesday, March 1, 2011

Commands used to administer Red Hat's Clustersuite


Checking status of the cluster
 # clustat
Moving a service/package over to another node
 # clusvcadm -r <servicename> -m <membername>
Starting a service/package
 # clusvcadm -e <servicename> -m <membername>
Stopping/disabling a service/package
 # clusvcadm -d <servicename>
Removing a node from the cluster
 # chkconfig ccsd off
 # chkconfig clvmd off
 # chkconfig cman off
 # chkconfig cmirror off
 # chkconfig fenced off
 # chkconfig gfs off
 # chkconfig rgmanager off
 # shutdown -r now
Gracefully halting the cluster
 # clusvcadm -d <servicename>
 **Do the following on each node:**
 # umount <GFS filesystems>
 # service rgmanager stop
 # service gfs stop
 # service clvmd stop
 # service fenced stop
 # cman_tool status
 # cman_tool leave
 # service ccsd stop
Gracefully starting the cluster (Done on each node)
 # service ccsd start
 # service cman start
 # service fenced start
 # service clvmd start
 # service gfs start
 # service rgmanager start
 # cman_tool nodes (shows status of nodes)