Mount SAN's Partition over Fiber cable for Linux

multipath -ll
fdisk -l
echo "1" > /sys/class/fc_host/host0/issue_lip
echo "1" > /sys/class/fc_host/host1/issue_lip
multipath -ll
fdisk -l
multipath -ll
pvcreate /dev/mapper/mpath4
pvdisplay
vgcreate vglog_file /dev/mapper/mpath4
lvcreate -L 100G vglog_file -n lvlog_file
lvcreate -L 99G vglog_file -n lvlog_file
mkfs.ext3 /dev/mapper/vglog_file-lvlog_file
mkdir logfile
mount -t ext3 /dev/mapper/vglog_file-lvlog_file /logfile/
chown sysadmin:root logfile/
echo "/dev/mapper/vglog_file-lvlog_file /logfile/ ext3 defaults 1 2">>/etc/fstab

Steve Jobs Memorial

We were very loved - We will be very missed; Thank you Steve!

Install and configure SNMP on RHEL or CentOS

This guide describe howto install and do a basic configure of SNMP on a RedHat Enterprise Linux or CentOS. Probably it will work on many other *nix systems.

1. Installation

Run command yum install net-snmp-utils

[root@dull etc]# yum install net-snmp-utils
Loading "fastestmirror" plugin
Loading "dellsysidplugin" plugin
...
...
Dependencies Resolved

=============================================================================
 Package                 Arch       Version          Repository        Size
=============================================================================
Installing:
 net-snmp-utils          i386       1:5.3.1-24.el5_2.2  updates           182 k
Installing for dependencies:
 net-snmp                i386       1:5.3.1-24.el5_2.2  updates           698 k

Transaction Summary
=============================================================================
Install      2 Package(s)
Update       0 Package(s)
Remove       0 Package(s)

Total download size: 879 k
Is this ok [y/N]: y

Answer y

Downloading Packages:

(1/2): net-snmp-utils-5.3 100% |=========================| 182 kB    00:02
(2/2): net-snmp-5.3.1-24. 100% |=========================| 698 kB    00:06
Running rpm_check_debug
Running Transaction Test
Finished Transaction Test
Transaction Test Succeeded
Running Transaction
 Installing: net-snmp                     ######################### [1/2]
  Installing: net-snmp-utils               ######################### [2/2]
Installed: net-snmp-utils.i386 1:5.3.1-24.el5_2.2
Dependency Installed: net-snmp.i386 1:5.3.1-24.el5_2.2
Complete!

Now it is installed

2. Configure

I’m careful so I do a backup of the snmpd config file.

[root@dull ~]# mv /etc/snmp/snmpd.conf /etc/snmp/snmpd.conf.org 

Create a new config file.

[root@dull ~]# vi /etc/snmp/snmpd.conf

rocommunity  public
syslocation  "PDC, Peters DataCenter"
syscontact  peter@it-slav.net

Start the snmpd service

[root@dull ~]# /etc/init.d/snmpd start

Do a snmpwalk to make sure it is working

[root@dull ~]# snmpwalk -v 1 -c public -O e 127.0.0.1
SNMPv2-MIB::sysDescr.0 = STRING: Linux dull 2.6.18-92.1.17.el5 #1 SMP Tue Nov 4 13:45:01 EST 2008 i686
SNMPv2-MIB::sysObjectID.0 = OID: NET-SNMP-MIB::netSnmpAgentOIDs.10
DISMAN-EVENT-MIB::sysUpTimeInstance = Timeticks: (16748) 0:02:47.48
SNMPv2-MIB::sysContact.0 = STRING: peter@it-slav.net
SNMPv2-MIB::sysName.0 = STRING: dull
SNMPv2-MIB::sysLocation.0 = STRING: "PDC, Peters DataCentral"
SNMPv2-MIB::sysORLastChange.0 = Timeticks: (1) 0:00:00.01
...

...

Yes, it is working

And finally, make sure snmpd starts next time you restart your machine.

[root@dull ~]# chkconfig snmpd on

3. Monitor example

Below is an example of how it looks using op5 Monitor a Nagios based Enterprise Monitor solution.

4. Useful links

• op5 Statistics, a cacti based graph tool
• op5 Monitor, an Enterprise Class Monitoring system based on Nagios
• Net-SNMP, an open source implementation of SNMP
• Cacti, an open source graph tool
• Nagios, the number 1 monitor tool