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28Jun/080

Xen VPS modprobe: QM_MODULES: Function not implemented

I got this problem on one of Debian VPS when tried to run iptables command

modprobe: QM_MODULES: Function not implemented
 
modprobe: QM_MODULES: Function not implemented
 
modprobe: Can't locate module ip_tables
iptables v1.3.6: can't initialize iptables table `filter': iptables
who? (do you need to insmod?)
Perhaps iptables or your kernel needs to be upgraded.

To fix this you'll need to run these commands:

11Jun/086

Meaning of /dev/null 2>&1 in Crontab’s Cron Job

If you use cron job on Linux, some times you want to ignore the output of the command you executed. This can be done by adding “> /dev/null 2>&1” behind the cron job command.

The command is just work want it should be, but I always curious with what does 2>&1 means. The “> /dev/null” is pretty obvious of what it does without much more explanation, it just redirect all the output to /dev/null which in Linux means we don’t care with the output (or sort of, it’s my own definition).

3Jun/082

Xen Debian VPS Problem With nash-hotplug Using 100% CPU Resource

Recently I setup a Debian 4.0 VPS using xen image from jailtime.org, once the VM running I noticed that the load goes 1.0 all the time which make the VM very slow. From top command you’ll see the nash-hotplug process is the cause.

First you can kill it by execute the ‘kill -9 <process id>’ command (without the quotes), where <process id> is the process id of nash-hotplug. Then to automate killing the nash process every time you reboot the VPS run these commands:

2Jun/087

PHP Unable to Connect to MS SQL Server Express Edition

I’ve been struggling for several hours to find out why PHP 5.2.5 didn’t want to connect to MS SQL Server 2005 Express Edition although extension=php_mssql.dll already enabled and phpinfo() is showing MS SQL already active.

I always got this error messages when trying to connect to MS SQL:

Warning: mssql_connect() [function.mssql-connect]: Unable to connect to server: (local)\SQLEXPRESS in path\mssql.php on line 5

After doing some searching, I got an answer that PHP 5 is using old ntwdblib.dll version. The one that comes with PHP 5.2.5 distribution is version 2000.2.8.0 which seems doesn’t compatible with the new MS SQL Server 2005 Express Edition. I downloaded new dll from http://webzila.com (use the search tool) which is version 2000.80.194.0 and replaced the one on PHP folder with this version.

I use this code to test the connection and its working:

 
echo("Testing MS SQL connection... ");
 
if ($conn = mssql_connect('(local)\SQLEXPRESS', 'user', 'pass'))
{
    echo("Connection succeed");
 
    mssql_select_db('dbname', $conn);
    mssql_close($conn);
}
else
{
    echo("Connection failed");
}
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