Tag: linux

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Software RAID support on Linux

Good RAID FAQ on Linux here.

Walkthrough on setting up a software RAID array here

Check RAID status:

<code>/sbin/mdadm --detail /dev/md0</code>

Or check with this:

<code>sudo cat /proc/mdstat</code>

This is what a good status will look like:

<code>
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] 
md1 : active raid1 sdb5[0] sdc5[1]
      1485888 blocks [2/2] [UU]
      
md0 : active raid1 sdb1[0] sdc1[1]
      242709888 blocks [2/2] [UU]
      
unused devices: <none>

The [UU] (I think) indicates the status of both drives in the array, and both are Up

Removing drives: sudo mdadm /dev/md0 -r /dev/sdb1

Adding drives back to the array: sudo mdadm /dev/md0 -a /dev/sdb1

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Setting up awstats for multiple virtual host logs

I only just realized recently that my apache2 config was outputting logs for my main domain into access.log, and all other virtual hosts into other_vhosts_access.log. As a result, awstats was not picking up hits to the majority of my sites.

To set up awstats to produce stats for each of my stats was relatively easy:

  • Config each virtual host in your apache2.conf to have it’s own CustomLog directive:
    <code><br />
    
&lt;VirtualHost *:80&gt;<br />
    
    ServerAdmin example@example.com<br />
    
    DocumentRoot /var/www/html/example<br />
    
    ServerName www.example.com<br />
    
    DirectoryIndex index.jsp index.html<br />
    
    CustomLog /var/log/apache2/access_example.log combined<br />
    
&lt;/VirtualHost&gt;<br />
    
</code></p>
    
<li>Copy your /etc/awstats/awstats.conf to awstats_example.conf – one per each domain where example is the domain name
    
<li>Edit each awstats.conf and change the log entry to point to the log file you added in the apache2.conf above, change the DataDir to be /var/awstats/example, and SiteDomain to e.g. example.com
    
<li>Create new subdirs for each DataDir in /var/awstats
    
<li>Run the stats collection manually to check working:
    
<pre><code>
    
sudo /usr/bin/perl /usr/lib/cgi-bin/awstats.pl -update -config=example.com
    
</code>
    

  • Update your cron entry to schedule the log processing, e.g. in /etc/cron.d/awstats:

    <code>
0,30 * * * * www-data [ -x /usr/lib/cgi-bin/awstats.pl -a -f /etc/awstats/awstats_example.com.conf -a -r 
/var/log/apache/access_example.log ] &#038;& /usr/lib/cgi-bin/awstats.pl -config=example.com -update >/dev/null
</code>
    

  • Add one line for each of the domains you need to collect log stats for. Done!

To access the stats for each of the domains, use the awstats config name passes as a param in the URL:

<code>
http://www.example.com/awstats/awstats.pl?config=example.com
</code>
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Setting up Nagios system monitoring on Ubuntu8.1 server

Latest package is nagios3 – to install:

<code>sudo apt-get install nagios3

A good article on setup and config is here.

To restart the Nagios server after making config changes: sudo /etc/init.d/nagios3 restart

Resolving CGI auth issues

Part of the install instructions above told me to create a user ‘nagios’, but the default config is setup to allow ‘nagiosadmin’ access to monitor services. Accessing the wepages you get this:

<code>"It appears as though you do not have permission to view information for
any of the hosts you requested... If you believe this is an error, check
the HTTP server authentication requirements for accessing this CGI and
check the authorization options in your CGI configuration file."</code>

To fix this, edit /etc/nagios3/cgi.cfg, and replace ‘nagiosadmin’ everywhere with ‘nagios’ (assuming the user you created was called ‘nagios’)

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