1.) What LVM is?

2.) Terminology

3.) Creation of Physical Vol, Volume Group, Logical Volume, Filesystem creation, Mount and making the FS entry in /etc/fstab

4.) Add new disk under existing Volume Group

5.) Filesystem extension in Linux

6.) Filesystem shrinking in Linux

7.) Removing disk from existing Volume Group

8.) Special Note

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Current trend of System Administration is Remote System Administration, and as a remote system administrator most of us having very less exposure to the Server hardware and their architecture.  For a system administrator it is always beneficial to know about the hardware that he is supporting remotely, this system hardware awareness helps him for quick decision making during the hardware troubleshooting. 

Here I am presenting you the server hardware diagrams ( Front View , Rear View, TOP Open Vierw) for various servers released by SUN-HARDWARE for the past one decade.

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In our previous post “Beginners Lesson – Veritas Cluster Services for System Admin” we have discussed the fundamentals of clustering and it’s purpose. In this post I would like to take you little deep inside of the clusters just to explore how the VCS communicating internally within a  cluster node ( intra-system Communication ) as well externally with all the cluster nodes ( inter system communication).

For the purpose of easy learning we will classify cluster communications as  below

1. Intra System Communications ( Inter process communications) – These communications happens among the components of VCS with in a single node.

2. Inter System Communications – These Communications happens in between the cluster nodes which are interconnected using cluster heartbeat network connections. And these communications are very important for VCS decision making regarding the failover and failback decision of individual service groups.

1. Intra System Communications

If we focus on a single node of VCS cluster, we will see 4 basic components that actually participates in the communication, and there are

a. Command line utilities

b. GUI ( Graphical User Interface Utilities)

c. Cluster Agents

d. High Availability Daemon ( HAD) called VCS engine

Within a system, the VCS engine (HAD) uses a VCS-specific communication protocol known as Inter Process Messaging (IPM) to communicate with the GUI, the command line, and the agents.

The agent uses the agent framework, which is compiled into the agent itself. For each resource type configured in a cluster, an agent ( e.g. sybase agent, oracle agent , nfs agent … )  runs on each cluster system. The agent handles all resources of that type. The engine passes commands to the agent and the agent returns the status of command execution. For example, an agent is commanded to bring a resource online. The agent responds back with the success (or failure) of the operation. Once the resource is online, the agent communicates with the engine only if this status changes Read Full

In this post we are basically covering the procedure to replace a failed disk under SVM in solaris. 

Replacement of a Failed Disk in Solaris (SVM – In Solaris Volume Manager)

TO REPLACE FAILED DISK IN THE SYSTEM:

First of all take the backups of following (necessary):
# metastat –p >/var/tmp/metastat-p-b4repalcement
# metastat –t >/var/tmp/metastat-t-b4replacement
# metadb –i >/var/tmp/metadb-i-b4replacement
# echo | format >/var/tmp/format-b4replacement
# iostat –en >/var/tmp/iostat-en-b4repalcement
# ifconfig –a >/var/tmp/ifconfig-a-b4repalcement

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Learning VxVM administration will be much easier by understanding below three things>

1. How Veritas Volume Manager treats Operating System Native Disks into Veritas Volumes

2. What are the operations we can do in VxVM and what commands are used to perform those operations

3. What are the background services/daemons/Configuration files required to make VxVM work in normal way

We have already covered the first Learning Objective from the post  ”Veritas Volume Manager for System Adminstrators ” . Read Full

The purpose of this post is to make the Cluster concept easy for those young brothers who have just started their career as System Administrator. while writing this post I have only one thing in mind, i.e. explain the entire cluster concept with minimum usage of technical jargon and make it as simple as possible.  That’s all about the introduction, let us go to actual lesson.

In any organisation, every server in the network will have a specific purpose in terms of  it’s usage, and most of the times these servers are used to provide stable environment to run software applications that are required for organisation’s business. Usually, these applications are very critical for the business,  and organisations cannot afford to let them down even for minutes.  For Example: A bank having an application which takes care of it’s internet banking. Read Full