Logical Partition

What is Logical Partition?

A logical partition refers to a specific partition on the hardware resources of a computer. This partition, also referred to as LPAR, is set aside and it acts as a virtual and additional computer.

Technically, these are divisions of multiple resource sets in a physical machine that acts as a virtual system with their respective illustrations of an operating system.

Understanding Logical Partition

A logical partition is a dedicated space within the hardware of a computer. It has its own resources to function independently.

This is because the resources available on the server are actually divided into small subsets when you create a logical partition.

Ideally, the main purpose of creating a logical partition is to provide the server with the ability to operate as if there are two or more separate servers, the number of which depends on the number of such partitions created.

You can even install other software on such partitions that act as virtual systems.

In addition to that, you can also assign the following to a logical partition:

• Memory
• Processors
• I/O devices

The logical partitions will typically share the resources between them, in spite of each having the ability to serve as a separate server.

This helps in enhancing utilization of resources on the server and also move them to areas where they are needed the most.

Here is the list of some of the ways in which the logical partitions share the resources between them, though, in some specific types of server models these may be optional and may need obtaining and entering an activation code:

• The micro-partitioning technology allows shared processing, where the processors are shared from the processor pools, thereby limiting the amount of power used by the logical partitions by the virtual processor settings. This also prevents wastage of unused power of the shared processor pool.
• The PowerVM Active Memory Sharing technology allows sharing memory pools. This is provided constantly by the hypervisor, eliminating the need for assigning a dedicated physical memory for each logical partition. Since the unused memory is used, this also prevents wastage of memory.
• The Dynamic Partitioning feature allows moving resources manually, when needed occasionally, to and from the running logical partitions and between them without requiring shutting down or restarting them.
• Virtual I/O allows using the I/O resources by the logical partitions such as virtual Ethernet by creating a virtual Local Area Network (LAN) to connect the different partitions on the server to each other.
• A Host Ethernet Adapter (HEA) or an Integrated Virtual Ethernet (IVE) will allow sharing of one single Ethernet adapter by multiple logical partitions on the same server, each connecting directly to the HEA and using its resources. This saves from the trouble of going through an Ethernet bridge on a separate logical partition.
• The Single Root I/O Virtualization (SR-IOV) tool will allow virtualization of the ports in an adapter with its extensions to the Peripheral Component Interconnect Express (PCIe) specification. This allows sharing of the ports by several partitions running at the same time.

Attributes

Logical partitions act quite efficiently to enhance the overall performance of the computer system since they share the same attributes as the parent partition. These are:

• The serial number of the system
• The system model
• The feature code of the processor

However, the other attributes of the system may vary from one logical partition to the next.

Tools

On a given server, you can create a lot of logical partitions, often numbering in the thousands. However, you will need to use the proper tools to create logical partitions on the servers. The selection of such tools will depend on specific factors such as:

• The operating system
• The server model
• The features you want to use on it

Some of the most commonly used tools for creating logical partitions are as follows:

• The Hardware Management Console – Often referred to as HMC, this tool will help you specially to construct, manage, and control one or more managed systems. You can also activate Capacity Upgrade on Demand. The tool will communicate with the managed system by using service applications and also to distinguish, combine, and send information to support and service for further analysis.
• The Integrated Virtualization Manager – This is actually a system management interface based on the browser used by the Virtual I/O Servers or VIOS. It will provide you with the capability to produce and manage logical partitions on one particular server.
• Virtual Partition Manager – This IBM i feature will allow you to create and manage a single host logical partition along with a maximum of four client logical partitions. These will typically run on either IBM i or Linux. This feature is typically used to create logical partitions on server systems that do not have or use HMC.

What Does a Logical Partition Do?

Ideally, a logical partition is a particular division on the storage, memory or the processor of the computer system that helps in storing different sets of resources, each of which can be used independently with its own operating system and run as autonomous server systems.

These partitions also help in using the dedicated hardware resources for different purposes, including but not limited to the following:

• Separating different productions
• Performing client/server operations
• Performing database operations
• Development purposes
• Quality assurance and other areas of production
• Consolidate servers
• Compute resources more efficiently
• Increase the flexibility

If there is adequate certification, such as Common Criteria EAL 5+, which is comparable to physically independent servers, a logical partition can also be used to support the highest level of security protocols, typically required in military use, and others.

Creating multi-client environments

Ideally, logical partitions allow for the creation of more multi-client environments. This will increase the availability quotient of the e-commerce services for a large number of clients.

The process allows each of the clients to configure and use the apps independently by using the computing resources and tech support offered to them.

This helps in isolating each client and will let them use the resources. It is much more cost-effective than providing a dedicated physical server to each, which will also reduce the amount of computing resources available to them.

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When one client stops using the service, the logical partition is deleted and the resources can be reassigned to other partitions.

Creating a separate test environment

A logical partition with separate resources on a managed system can also be used for creating separate test environment by removing resources from the production environments.

By using dynamic partitioning, this helps in testing peak production demand and inventory application and management.

Integrating new company acquisitions

All companies do not use the same applications for inventory, billing, payroll, and others. If you acquire another company, logical partitions can help in integrating the two on a single set of applications. This will reduce time and data center costs.

If you need more processing power and memory for the combined workloads, you can even use Capacity Upgrade on Demand (CUoD) on the managed system and dynamic partitioning to get the best results by using a single application set.

In short, a logical partition in the hardware resources on the same server offers significant benefits such as:

• Faster deployment
• Lower cost
• More convenience
• Sharing resources
• Maintaining independent servers
• Running integrated clusters

Can You Delete a Logical Partition?

Yes, you can delete a logical partition along with all other profile partitions that are related to it. However, if the particular partition is the service logical partition of the managed system, you will not be able to delete it easily.

If you want to delete a service logical partition, you will have to create another logical partition that will perform as a service logical partition on your managed system.

Alternatively, you may remove the partition designation from the logical partition.

Preparation:

Normally, there are also a few preparations required before you go ahead and delete a logical partition.

• Shut down the logical partition you want to delete.
• If it is a Virtual I/O Server logical partition assigned to the shared memory pool you want to delete, remove it from the pool.

Ideally, in order to delete a logical partition, you will need to use specific hardware management tools and utilities such as Hardware Management Console (HMC).

You will have to complete the following steps in order to delete a logical partition:

• Click on the Resources image on the navigation pane
• Click on All Partitions
• Select the logical partition on the page displayed
• Click on Tasks
• Select Delete Partition
• Click OK

If you do not find the Delete Partition option straightaway, you may first go to the Cleanup associated Virtual I/O Server mappings check box and then click on the Delete associated virtual disks check box.

If you are deleting a logical partition using a shared memory, the hardware management tool will perform the following tasks:

• It will remove the shared memory partition from the pool of shared memory.
• It will return the physical memory assigned to the shared memory partition for the I/O devices to the shared memory pool so that it can be assigned to other shared memory partitions.
• It will release the paging space device designated for the shared memory partition to make it available for use by the shared memory partitions.

However, you must remember that the process will delete the logical partition and all data stored on the partition profiles along with it.

And if the logical drive is the only one in the array, then the entire array will be deleted.

If that is the case, then you may use the Unified Extensible Firmware Interface or UEFI System Utilities or Shell Command, depending on the system, and follow these steps:

• Select System Configuration
• Select the controller
• Click on Array Configuration
• Select Manage Arrays
• Go to the array
• Select List Logical Drives
• Select the logical drive
• Click on Delete Logical Drive
• Click on Submit Changes on the Delete Logical Drive screen

Logical Partition Vs Primary Partition

• A logical partition is actually a logical division of the memory and other resources of the mainframe that acts as a separate virtual computer. On the other hand, a primary partition refers to the actual partition of the hard disk for storing the Windows operating system and other data.
• A logical partition will allow running its copy of the operating system and other allied programs, but in comparison the primary partition can only boot the legacy Master Boot Record (MBR) bootloader from the primary partition.
• A logical partition cannot support Windows booting from it, but a primary partition, in comparison, will. In fact, you will not be able to boot your computer without a primary partition.
• The number of logical partitions existing in a system can be unlimited, depending on the operating system and the processor model and can be assigned with a drive letter and formatted separately. On the other hand, there can only be four primary partitions existing on a single disk.
• A logical partition is not bootable and cannot help in booting the computer system. On the other hand, a primary partition is essentially bootable and can boot your computer.
• Multiple logical partitions on a hard disk are typically described by using multiple Extended Boot Record (EBR). On the other hand, multiple primary partitions are described by using only one partition table contained in the Master Boot Record.
• The logical partitions on a hard disk are usually represented by the letters E, F, G, and others. On the other hand, the primary partitions are typically assigned the English alphabets C and D.
• The logical partitions cannot be set as active though it allows saving data on them. On the other hand, any of the four primary partitions can be set as active, which will be typically recognized by the Basic Input Output System (BIOS) for loading the operating system.
• Typically, there are no logical partitions in a Globally Unique Identifier Partition Table (GPT) disk. On the other hand, you can have up to four primary partitions on a GPT disk as well.
• If you want to resize, the logical partitions in a system can be unmounted. However, in comparison, the primary partitions cannot be unmounted because they hold the running operating system in them.

Can You Install Windows on a Logical Partition?

Yes, you can install Windows on a logical partition, but there are a few specific things to remember. This should be done in the extended partition. Also, you will have to boot Windows from a primary partition.

Conclusion

A logical partition is very useful for better hardware resource allocation and utilization along with time management, and through this article, you know how.

However, in spite of the benefits provided, it has some specific downsides, such as failure of the entire server due to failure of the processor and memory.