Overview on ZFS ( in a comic style) :

What is ZFS?

ZFS is a Solaris file system that uses storage pools to manage physical storage. The ZFS pooled storage model eliminates the concept of volumes and the associated problems of partitions, provisioning and stranded storage by enabling thousands of file systems to draw from a common storage pool, using only as much space as it actually needs. ZFS also uses RAID-Z, a data replication model that is similar to RAID-5 but uses variable stripe width to eliminate the RAID-5 write hole—that is stripe corruption due to loss of power between data and parity updates. All RAID-Z writes are full-stripe writes. There's no read-modify-write tax, no write hole, and no need for NVRAM in hardware.

According to the FAQ posted on OpenSolaris.org, originally, ZFS was an acronym for "Zettabyte File System." The largest SI prefix that the developers liked was 'zetta', and since ZFS is a 128-bit file system, the name was a reference to the fact that ZFS can store 256 quadrillion zettabytes (where each ZB is 270 bytes). Over time, ZFS gained a lot more features besides 128-bit capacity, such as rock-solid data integrity, easy administration, and a simplified model for managing your data.

ZFS is open-source software that is licensed under the Common Development and Distribution License (CDDL).

 

 

 

 

 

 

Some Colorful diagrams showing operating system features in a different way:

Some Colorful diagrams showing operating system features in a different way:

1) Computer Operating Systems.

 

2) Unix Like Operating Systems Map.

 

3) Unix Linux Time Line.

 

4) Map of GNU/Linux OS and FOSS.

 

5) Linux FileSystem Hierarchy.

 

6) Linux LVM.

 

7) Linux Kernel Map.

 

8) Network Protocol Map.

 

9) Network Management Architecture and Technologies.

 

10) Network Security Map.

Installing Nagios in Linux (Fedora/Red hat):

My experience while installing Nagios on my RHEL5 machine:

After hearing a lot about Nagios I finally thought I should give it a try, there started my 3 days of struggle. As I’m working in an IT company I do get very less time to experiment on anything.

On day one I started installing Nagios by following the steps given in the Nagios documentation, everything went fine and no errors were found and Nagios installed successfully I thought I have made it in the first attempt itself then I have opened the link http://<MY IP ADDRESS>/nagios in the browser while I started to browse through the options the problem started, except the home and documentation page none were working.

Error displayed as:

Not Found
The requested URL /nagios/cgi-bin/statusmap.cgi was not found on this server

And it also displayed another error regarding the permission issue, I tried a lot to troubleshoot the issue but unsuccessful.

The second day I Google on this issue and found that lot many people have faced the same problem I tried all the solutions but none were helping my cause. Two days went by in dejection.

Third day I started off right from scratch and succeeded, so finally my nagios started working on my machine for the first time it was like a sigh of relief to me .

“As I’m a newbie in this Linux ocean, every minor success is like a power booster to me. ”

So with this success I can go and try more configurations on my machine and I’ll keep updating you..

“I have started my long journey into Linux with first step “

Here I’m posting the steps I have followed to configure my nagios, so that none of you should waste your valuable time.

 

Steps to install Nagios on Linux:

1) Before installing Nagios, ensure that the following packages are installed:

   a) Apache

   b) PHP

   c) GCC Compiler

   d) GD development libraries

If not, login as root and install it.

[root@localhost ~]$yum install httpd php gcc glibc glibc-common

[root@localhost ~]$:yum install gd gd-devel

 

2) Now we have to create a user account and a group for Nagios. Also add the apache user account to the created group.

Become root user and type:

[root@localhost ~]$useradd -m nagios

[root@localhost ~]$passwd nagios

[root@localhost ~]$groupadd nagcmd

[root@localhost ~]$usermod -a -G nagcmd nagios

[root@localhost ~]$usermod -a -G nagcmd apache

 

3) Create a temporary folder for the downloads and download the latest version of Nagios Core and plugins.

http://www.nagios.com/download

[root@localhost ~]$mkdir downloads

[root@localhost ~]$cd downloads

 

4) Extract the Nagios tarball

[root@localhost ~]$cd downloads

[root@localhost downloads]$tar xvzf nagios-3.x.x.tar.gz

[root@localhost downloads]$cd nagios-3.x.x

 

5) After this, we need to compile and install.

[root@localhost nagios-3.x.x]$ ./configure -–with-command-group=nagcmd

[root@localhost nagios-3.x.x]$make all

[root@localhost nagios-3.x.x]$make install

[root@localhost nagios-3.x.x]$make install-init

[root@localhost nagios-3.x.x]$make install-config

[root@localhost nagios-3.x.x]$make install-commandmode

 

6) Install the Nagios web config file in the Apache conf.d directory.

[root@localhost nagios-3.x.x]$make install-webconf

 

7) Use the htpasswd to create an account for logging into the Nagios web interface.

[root@localhost nagios-3.x.x]$ htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadmin

 

8) Extract the Nagios plugins tarball

[root@localhost ~]$cd downloads

[root@localhost downloads]$tar xvzf nagios-plugins-1.4.x.tar.gz

[root@localhost ~downloads]$cd nagios-plugins-1.4.x

 

9) After this, we need to compile and install.

[root@localhost nagios-plugins-1.4.x]$ ./configure --with-nagios-user=nagios --with-nagios-group=nagios

[root@localhost nagios-plugins-1.4.x]$make

[root@localhost nagios-plugins-1.4.x]$make install

 

10) Check the Nagios configuration for errors.

[root@localhost ~]$/usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg

 

11) If there are no errors, start Nagios

[root@localhost ~]$service nagios start

Or

[root@localhost ~]$/etc/init.d/nagios start

 

12) To start Nagios when the system boots type:

[root@localhost ~]$chkconfig --add nagios

[root@localhost ~]$chkconfig nagios on

 

13) If you have SELinux installed and with the enforcing mode by default, you probably get some errors in Nagios web interface.

You'll need to change the SELinux context of some Nagios folders.

chcon -R -t httpd_sys_content_t /usr/local/nagios/sbin/

chcon -R -t httpd_sys_content_t /usr/local/nagios/share/

chcon -R -t httpd_sys_script_rw_t /usr/local/nagios/var/rw/

 

 

 

 

 

Thats all floks !!!!