How to make bridge over VLAN?Bridging over VLAN's :By constructing a bridge between a "normal" and a "VLAN" ethernet interface, the Linux computer will add and remove the VLAN headers on behalf of any other device(s) plugged into the "normal" card.How :Okay, now for the tricky part. It takes a slight modification of the procedures above. For this example, let's presume we have an Ethernet interface eth0 connected to the network where a VLAN id 2 is present, and we have a device or devices on eth1 that need to be bridged into that VLAN 2.Go ahead...
Thursday, 30 June 2011
How to setup VLAN network on linux ?
Posted on 23:23 by Unknown
How to setup VLAN network on linux ?Why VLAN : create a virual lan(grouping some computers from actual LAN with out using any switch/routers etc. Only needs software. Can also be done using hardware)Required Packages :#yum install vconfigNext, go to the /etc/sysconfig/network-scripts directory and decide which eth# device you're going to add a VLAN to. Note that the VLAN device will run alongside (in parallel to, at the same time) as the original eth# device, so there is no need to change your existing configuration.1. copy /etc/sysconfig/network-scripts/ifcfg-eth0...
How to configure network bridge / VLAN on linux machine?
Posted on 23:22 by Unknown
Setup bridge network :Why bridge : Virtually connect multiple Ethernets in one interface(virtual). May be wireless and physical Ethernet will be connected together for communication.Install required package :#yum install bridge-utilsLet machine has two NIC eth0 and eth1 :So, change it like :1. vi /etc/sysconfig/network-scripts/ifcfg-eth0 ---DEVICE=eth0TYPE=EthernetHWADDR=##:##:##:##:##:##ONBOOT=yesBRIDGE=br0---2. vi /etc/sysconfig/network-scripts/ifcfg-eth1---DEVICE=eth1TYPE=EthernetWADDR=##:##:##:##:##:##ONBOOT=yesBRIDGE=br0---3. create a file...
Thursday, 23 June 2011
How to scan newly added LUN using rescan-scsi-bus.sh ?
Posted on 02:31 by Unknown
ENV : RHEL 5.4 and laterI suggest you NOT to scan the existing LUNs since I/O operations are still in use and if you scan them it will/may corrupt the file system. So, I always suggest you to scan the new added device or storage. Once you add it, HBA will detect the device and then you can scan this non-existent LUNs to the HBA. As an example you can execute the command like :---#rescan-scsi-bus.sh --hosts=1 --luns=2---Note : I assume that on host 1/or on HBA 1, lun 2 doesn't exist.For more details please get help from :---#rescan-scsi-bus.s --helphttp://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5/html/Online_Storage_Reconfiguration_Guide/rescan-scsi-bus.html---Try...
Friday, 17 June 2011
Basic Idea about GFS file system!
Posted on 09:16 by Unknown
Global File System (GFS) is a shared disk file system for Linux computer clusters. It can maximize the benefits of clustering and minimize the costs. It does following :# Greatly simplify your data infrastructure# Install and patch applications once, for the entire cluster# Reduce the need for redundant copies of data# Simplify back-up and disaster recovery tasks# Maximize use of storage resources and minimize your storage costs# Manage your storage capacity as a whole vs. by partition# Decrease your overall storage needs by reducing data duplication#...
what does it mean by "cman expected_votes="1" two_node="1" in cluster.conf ?
Posted on 05:32 by Unknown
For two node clusters ordinarily, the loss of quorum after one out of two nodes fails will prevent the remaining node from continuing (if both nodes have one vote.) Special configuration options can be set to allow the one remaining node to continue operating if the other fails. To do this only two nodes, each with one vote, can be defined in cluster.conf. The two_node and expected_votes values must then be set to 1 in the cman section as follows.---cman two_node="1" expected_votes="1" ...
Thursday, 16 June 2011
How to list out number of files inside each directory?
Posted on 10:16 by Unknown
I developed following script and used it :---[root@vm68 log]# cat ./find_large_small_files.sh#!/bin/bashfind . -type d -exec ls -d {} \; &> ./tmpfilelet i=0for i in `cat ./tmpfile` do echo "Directory $i has following no of files : `ls -al $i|wc -l`"done---Try and modify as per your ne...
Monday, 13 June 2011
How to enable debugging log level in postfix?
Posted on 23:48 by Unknown
Add the following lines in /etc/postfix/main.cf file ::---debug_peer_list = example.comdebug_peer_level = 2---Here example.com is the domain for which log messages will be displayed.And enable -v -v in master.cf file(/etc/postfix/master.cf) like :---smtp unix - - n - - smtp -v -vsmtp inet n - n - - smtpd -v -v---Restart postfix. check /var/log/maillog...
Thursday, 9 June 2011
Use of smartctl to probe SATA?
Posted on 06:17 by Unknown
To check hardware on linux(HW diagnosis tool):smartctl tool can't properly read SMART parameters from SATA devices. However, recent development of libata package makes it easy to read the data. You should use "ata" option while you probe the hardware. So, exact command will be :---#smartctl -d ata -A /dev/sdb ---To enable SMART on the SATA device you should use the following command :---#smartctl -s on -d ata /dev/sdb---Then enable SMART :---#smartctl -s on -d ata /dev/sdb---Now run overall-health self-assessment test:---# smartctl -d ata -H /dev/sdb---You...
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