Perhaps you have copied some configuration files from another system and those files have not been yet “indexed” (relabeled) by SELinux. In this case SELinux is assuming them as “alien” files and thus the resulting error.

Disabling SELinux IS NOT AN OPTION! You should solve the issues that prevents your linux system from working properly, WITHOUT DISABLING SELinux.

Relabel the systemfile at boot time:

[root@linux hack]# touch /.autorelabel && reboot

SELinux can be disabled completely at bootup by passing selinux=0 to the kernel command line. This will completely disable SELinux until a reboot, and you will need to relabel files when rebooting to ensure proper operation.

If you cannot afford a reboot then take a look at the SElinux fixfiles command:

[root@linux hack]# /sbin/fixfiles check

fixfiles can be used to relabel the entire filesystem based on the current policy, or to relabel a packaged application’s files based on the information included in that application’s rpm package.

A better alternative for temporarily disabling SELinux is to put the system into permissive mode. Permissive mode will log actions that would have been denied, but will not actually deny them. This contrasts with the normal enforcing mode that will actively deny access to actions not explicitly allowed by the currently running policy.
To put the system into permissive mode, issue the command setenforce 0 while in the sysadm_r role or pass enforcing=0 to the kernel command line at bootup. To resume enforcing mode, issue the command setenforce 1. Issuing the command getenforce will return the mode SELinux is running currently.
SELinux modes can also be set by editing the SELinux config file located at /etc/selinux/config. The SELINUX= line can be set to enforcing, permissive, or disabled, and will take effect upon the next reboot.

SELinux status:

[root@linux hack]# [root@linux hack]# cat /selinux/enforce

Enable SELinux:

[root@linux hack]# echo 1 > /selinux/enforce

Disable SELinux:

[root@linux hack]# echo 0 > /selinux/enforce

Further reading about SELinux Administration can be found here: http://bit.ly/AkNz75 here: http://bit.ly/AzFiTA nd here: http://bit.ly/AzFiTA

This section explains how to use GPU Passthrough to assign a PCI graphics card to a guest operating system.

The following is a detailed step-by-step guide for XenServer, provided that your system meets the hardware and firmware requirements described above.

How to solve:

- Log in to your host (XenServer) using the console or ssh;
[root@xenserver]# cd /opt/xensource/packages/files/transfer-vm
[root@xenserver]# ls -l
total 3684
-rw-r--r-- 1 root root 134 May 20 2010 65-install-transfer-vm
-rwxr-xr-x 1 root root 478 May 20 2010 do-copy
-rwxr-xr-x 1 root root 613 May 20 2010 do-transfer
-rwxr-xr-x 1 root root 1784 May 20 2010 install-transfer-vm.sh
-rw-r--r-- 1 root root 3747840 May 20 2010 transfer-vm.xva
-rwxr-xr-x 1 root root 491 May 20 2010 uninstall-transfer-vm.sh
[root@xenserver]# ./install-transfer-vm.sh script
Importing XenServer Transfer VM... done.


Now you can go back to XenCenter and start your virtual hard drive image Import.
Further explanations and troubleshooting can be found here .

Clear the CMOS after bios upgrade and your new bios should now recognize your cd-rom and other removable media like usb.

Here are some network configuration tools (depending on your system you might not have some of them)

Check their availabillity with the whereis command, ex:
[root@linux hack]# whereis netconf

These programs will modify values in the following files:

• /etc/sysconfig/network – Defines your network and some of its characteristics.
• /etc/HOSTNAME – Shows the host name of this host. IF your name is “myhost” then that is exactly the text this file will contain.
• /etc/resolv.conf – Specifies the domain to be searched for host names to connect to, the nameserver address, and the search order for the nameservers.
• /etc/host.conf – Specifies the order nameservice looks to resolve names.
• /etc/hosts – Shows addresses and names of local hosts.
• /etc/networks – Provides a database of network names with network addresses similar to the /etc/hosts file. This file is not required for operation.
• /etc/sysconfig/network-scripts/ifcfg-eth* – There is a file for each network interface. This file contains the IP address of the interface and many other setup variables.

Analysis Tools

• netstat – Displays information about the systems network connections, including port connections, routing tables, and more. The command “netstar -r” will display the routing table.
• traceroute – This command can be used to determine the network route from your computer to some other computer on your network or the internet. To use it you can type “route IPaddress” of the computer you want to see the route to.
• nslookup – Used to query DNS servers for information about hosts.
• arp – This program lets the user read or modify their arp cache.
• tcpdump – This program allows the user to see TCP traffic on their network.
• dig(1) – Send domain name query packets to name servers for debugging or testing.

source: http://www.comptechdoc.org/os/linux/usersguide/linux_ugbasicnet.html

[root@linux hack]# route add -net 10.1.0.0 netmask 255.255.0.0 gw 10.2.0.1 eth0
[root@linux hack]# route add -host 10.10.0.5 netmask 255.255.0.0 gw 10.2.0.1 eth0

- Adding a default route by using route command.

[root@linux hack]# route add default gw 10.10.0.1 eth0

If you use dhcp (dhcpclient) and encounter the error in discussion then you might want to check your dhcpserver configuration and also the ip class(subnet) allocation. If you have not properly configured the dhcp server so that it serves the right broadcast address and gateway you will encounter the error.
Here is an IP calculator that is very helpful …

some info from:  http://www.labtestproject.com/linnet/routing.html

A: No. DDR2 memory modules have basically the same dimensions as the DDR modules, but because of different voltages and pin configurations, DDR2 modules have a different “key” or notch in their connector to prevent them from being plugged into an incompatible socket. DDR2 memory modules will only fit in systems and motherboards designed to specifically support DDR2 memory. A DDR2 SODIMM will not fit in the DDR memory slot.

[SOLUTION]
In your “system” folder from your CI core files edit this file /database/drivers/msyql/mysql_driver.php, in line 125, by replacing the function “db_set_charset” with the following one.

	/**
	 * Set client character set
	 *
	 * @access	public
	 * @param	string
	 * @param	string
	 * @return	resource
	 */
	function db_set_charset($charset, $collation)
	{
		static $use_set_names;

		if ( ! isset($use_set_names))
		{
			// mysql_set_charset() requires PHP >= 5.2.3 and MySQL >= 5.0.7, use SET NAMES as fallback
			$use_set_names = (version_compare(PHP_VERSION, '5.2.3', '>=') && version_compare(mysql_get_server_info(), '5.0.7', '>=')) ? FALSE : TRUE;
		}

		if ($use_set_names)
		{
        // not supported on some servers (i.e. mediatemple)!
        if(function_exists('mysql_set_charset'))
            return mysql_set_charset($charset, $this->conn_id);
        else
            return @mysql_query("SET NAMES '".$this->escape_str($charset)."' COLLATE '".$this->escape_str($collation)."'", $this->conn_id);
		}
	}

This should get you going!

Source: Code Igniter forum

If you have a wordpress.com account just login and follow this link:

http://apikey.wordpress.com/

SCENARIO 1:
If we are using the mysql NOW() and CURDATE() native function the query would look like this:

 SELECT product FROM table WHERE dateX <= NOW() and dateY >= CURDATE() 

SCENARIO 2:
If we use PHP date(“Y-m-d”) and assume the variable

 $php_date = date("Y-m-d"); 

the query would be sth. like:

 SELECT product FROM table WHERE dateX <= '$php_date' and dateY >= '$php_date'  

CONCLUSION:
I noticed a HUGE LACK in PERFORMANCE while using the native MySQL NOW() and CURDATE() function as opposed to the second scenario when using the string date generated by the php date function.

On a particular project, I work at, the page load was affected by a difference of more than 8 Seconds which is unacceptable.

As always I look forward to your comments…