CS & IT Solutions

KernelTo successfully run enterprise applications, such as a database server, on your Linux distribution, you may be required to update some of the default kernel parameter settings. For example, the 2.4.x series kernel message queue parameter msgmni has a default value (for example, shared memory, or shmmax is only 33,554,432 bytes on Red Hat Linux by default) that allows only a limited number of simultaneous connections to a database. Here are some recommended values (by the IBM DB2 Support Web site) for database servers to run optimally:

Shared Memory

Semaphores

ulimits

Message queues Read the rest of this entry »

Manage Time in Ubuntu Through Command Line

What if you would like to manage your computer’s time in Ubuntu? It’s easy if you are in a graphical desktop environment. But what if you are on the command line? For example, in Ubuntu Server? Well, it is easy as well. A very helpful, everything-in-one-place resource is Ubuntu Time.

View Time

To view the current date and time, the following command will be enough

date

Set Time

To change time means to set a new time. To set time in Ubuntu (or any Linux), just run the following command

sudo date newdatetimestring

where newdatetimestring has to follow the format nnddhhmmyyyy.ss which is described below

• nn is a two digit month, between 01 to 12
• dd is a two digit day, between 01 and 31, with the regular rules for days according to month and year applying
• hh is two digit hour, using the 24-hour period so it is between 00 and 23
• mm is two digit minute, between 00 and 59
• yyyy is the year; it can be two digit or four digit: your choice. I prefer to use four digit years whenever I can for better clarity and less confusion
• ss is two digit seconds. Notice the period ‘.’ before the ss.

Let’s say you want to set your computer’s new time to December 6, 2007, 22:43:55, then you would use:

sudo date 120622432007.55

It couldn’t be any easier, could it? The source of this information was a good post on Ubuntu Forums (Set time/date via command line).

Change Time Zone

You may update or change your time zone by

tzconfig

This command will guide you through the process of setting a new time zone. You may also choose UTC (GMT) if you want.

If your system does not have tzconfig, you may use something else.

tzselect

This will provide a set of different time zones to choose. If you would like to set the time to UTC, choose the option which says something like ‘none of the above’, or ‘none of these’ or something to this effect. In my case it was option 11. Then it asks for difference from UTC (GMT and GST is also the same thing). I chose GST-0 as the option and it set the time as UTC.

Sync Clock Via NTP

If you want to sync your clock with NTP servers, it is also very easy. Just make sure you have the file ntp.conf file in /etc. How can you check it?

ls /etc/ntp.conf

If you see /etc/ntp.conf as a result, you already have that file. If the ls command gives an error, you do not have it. If so, you may create it yourself.

sudo vim /etc/ntp.conf

This file will be used to automatic synchronization of the clock. I do not know if the client uses this file automatically or one has to configure something first.

Whether you have the file already or not, make sure it has at least the following data

driftfile /var/lib/ntp/ntp.drift
server 0.pool.ntp.org
server 1.pool.ntp.org
server 2.pool.ntp.org
server pool.ntp.org

Here you may replace, add, and/or remove any servers you wish. You will find a list of time servers from the public NTP time server list.

You may manually sync the clock using the following

sudo ntpdate servername

where servername can be any public or private time server. You may always choose the following without hesitation

sudo ntpdate pool.ntp.org

See, it was quite easy. Enabling NTP Services helped me gain this knowledge.

source here

rm -f /backup/mysql*
### System Setup ###
BACKUP=/backup
NOW=$(date +”%d-%m-%Y”)

### MySQL Setup ###
MUSER=”mysqluser”
MPASS=”password”
MHOST=”localhost”
MYSQL=”$(which mysql)”
MYSQLDUMP=”$(which mysqldump)”
GZIP=”$(which gzip)”

### Start MySQL Backup ###
# Get all databases name
DBS=”$($MYSQL -u $MUSER -h $MHOST -p$MPASS -Bse ‘show databases’)”
for db in $DBS
do
FILE=$BACKUP/mysql-$db.$NOW-$(date +”%T”).gz
$MYSQLDUMP -u $MUSER -h $MHOST -p$MPASS $db | $GZIP -9 > $FILE
done

source here

DNS (Domain Name Service) server is a server that translate an IP address into a name that will be easy to remember or do the opposite way.

The administrative job is done in Server side. For client side just set the machine to connect the DNS server.

Before we start, I assume that you are connected to Internet already. For, text editor, you can use any program that you are familiar with. In this sample, I use vim.

The installation is as easy as below:

Step 1. Install the bind9

Open Linux Terminal (Applications>Accessories>Terminal), type: sudo apt-get install bind9

Installation finished.

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