Archive for the 'General' Category

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Using system-config-lvm

Using system-config-lvm

The LVM utility allows you to manage logical volumes within X windows or graphically. You can access the application by selecting from your menu panel System > Administration > Logical Volume Management.

Alternatively you can start the Logical Volume Management utility by typing system-config-lvm from a terminal.

To initialize a partition or unpartioned space, select the partition and click on the Initialize Entity button. Once initialized, a volume will be listed in the ‘Unallocated Volumes’ list.

To add the volume to an existing volume group, click on the Add to Existing Volume Group button. Clicking on the Add to Existing Volume Group button will display a pop up window listing the existing volume groups to which you can add the physical volume you are about to initialize. A volume group may span across one or more hard disks.

Once added to an existing volume group the new logical volume is automatically added to the unused space of the selected volume group.

SBDavid

IPv6 Addresses Types

IPv6 Addresses Types

IPv6 addresses are broadly classified into three categories:

1) Unicast addresses A Unicast address acts as an identifier for a single interface. An IPv6 packet sent to a Unicast address is delivered to the interface identified by that address.

2) Multicast addresses A Multicast address acts as an identifier for a group/set of interfaces that may belong to the different nodes. An IPv6 packet delivered to a Multicast address is delivered to the multiple interfaces.

3) Anycast addresses Anycast addresses act as identifiers for a set of interfaces that may belong to the different nodes. An IPv6 packet destined for an Anycast address is delivered to one of the interfaces identified by the address.

SBDavid

Flushing DNS Cache on your system

Flushing DNS Cache on your system.

When your computer visits a website for the first time, it stores the website’s DNS information in a local cache.

The instructions unique to particular operating systems are below.

From the command line on a windows operating system type:

ipconfig /flushdns

From a Linux operating system.

/etc/init.d/nscd restart

Nscd is a daemon that provides a cache for the most common name service requests

From MAC on the terminal window

dscacheutil -flushcache

Directory Service (DNS) cache - Gather information, statistics, initiate queries, flush the cache. dscacheutil replaces most of the functionality of thelookupd tool provided prior to OS X Leopard.

SBDavid

Authoritative DNS

Authoritative DNS

Each domain has at least one authoritative DNS server that publishes information about that domain and the name servers of any domains subordinate to it. The top of the hierarchy is served by the root nameservers, the servers to query when looking up (resolving) a top-level domain name (TLD).

An authoritative name server can either be a master server or a slave server.

Authoritative DNS is the type of DNS that controls the DNS records for a particular domain. For instance, for serverbuddies.com the authoritative DNS servers are ns1.serverbuddies.com and ns2.serverbuddies.com. They only respond to domains they are in charge of.

Contrast this with Recursive DNS are those servers which will give you and answer for any thing. (Google.com, yahoo.com)

SBDavid

The /usr/local Directory

The /usr/local Directory

“The /usr/local hierarchy is for use by the system administrator when installing software locally. It needs to be safe from being overwritten when the system software is updated. It may be used for programs and data that are shareable amongst a group of hosts, but not found in /usr.”

The /usr/local directory is similar in structure to the /usr directory. It has the following subdirectories, which are similar in purpose to those in the /usr directory.

/usr/local
|- bin
|- doc
|- etc
|- games
|- include
|- lib
|- libexec
|- sbin
|- share
|- src

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