Local VHD Image Update Guide

This document introduces how to use the commands on the server to update the local VHD images on the client, as well as the status and options during the update process.

Image Update Overview

Image and Restore Point Update Method

The local VHD image is a virtual hard disk file used for offline booting, which contains data such as the operating system and applications. The restore point is a version of the image file, which can be used to restore or roll back to a certain point in time.

The image and restore point are updated in a block-by-block manner, only updating the changed blocks, which can save time and bandwidth. When updating, a temporary file is created first, copying the same blocks from the local and downloading the different blocks from the server or update source. After the update is completed, the temporary file is renamed to the new version of the file.

Image Update Steps and Status

The new version of the file needs to be installed to the boot loader to start. After installation, you need to restart the computer to take effect.

The image update is divided into three steps:

• Step 1: Create a temporary file, copy and download blocks.
• Step 2: Rename the temporary file and install it to the boot loader.
• Step 3: Restart the computer and complete the update.

The image update has four statuses:

• Unfinished update: Step 1 has not started or has not been completed.
• Waiting for installation: Step 1 is completed, waiting for installation or executing step 2.
• Waiting for restart: Step 2 is completed, waiting for restart or executing step 3.
• Completed update: Step 3 is completed, update is completed, status after restart.

Image Update Commands

The image update commands are divided into two categories:

• Manual update commands: One-time commands executed on the server to update the image on the client. The client can also save them when offline, and execute them when online.
• Automatic update commands: Setting commands executed on the server to update the image on the client. The client will automatically execute them as long as it meets the update conditions.

Manual Update Commands

There are several manual update commands:

• Manual update: Manually execute the next step.
• Manual update and install: Manually execute the next step until installation is complete.
• Manual update and restart: Manually execute the next step until restart.
• Manual update and delay restart: Manually execute the next step until delay restart.

Automatic Update Commands

There are several automatic update commands:

• Automatic update: Automatically execute the next step when meeting the update conditions.
• Automatic update and install: Automatically execute the next step until installation is complete when meeting the update conditions.
• Automatic update and restart: Automatically execute the next step until restart when meeting the update conditions.
• Automatic update and delay restart: Automatically execute the next step until delay restart when meeting the update conditions.
• Forced update: When meeting the update conditions, lock the screen and perform an update at startup, not allowing users to cancel.
• Automatic startup and perform an update: When meeting the update conditions, automatically wake up the computer in shutdown state, lock the screen and perform an update, not allowing users to cancel.

Delay Restart Option

The delay restart option means that after the update is completed, it will restart after a period of time. This allows the client to restart when it is not busy, avoiding affecting user usage.

The delay restart option has two parameters: effective time and idle time. Within the effective time range, if there is no user operation reaching idle time, it will restart.

P2P Update

P2P update is a technology that uses the network connection between clients in a local area network to share and transfer image and restore point files, thereby reducing the traffic demand on the server.

P2P update supports four modes, which can be selected according to different scenarios and needs:

• Update only from server: The client only obtains image and restore point files from the server, and does not use the P2P network.
• Update only from update source: The client only obtains image and restore point files from the specified update source, and does not use the server or other clients.
• Update automatically from server and update source: The client prefers to obtain image and restore point files from the specified update source, and if the update source is unavailable or slow, it obtains them from the server.
• Update automatically from all clients: The client prefers to obtain image and restore point files from other clients in the local area network, and if there are no available clients or they are slow, it obtains them from the server.
• Update automatically from all clients and server: The client obtains image and restore point files from both other clients in the local area network and the server, and automatically adjusts the download speed according to the network condition.

The P2P update source list refers to the specified update source IP addresses that the client looks for when updating in the local area network. The update source list is configured by the user, and can be other clients or dedicated servers.