The LRS module's index page contains a list of all host names currently registered (e.g. declared) on the LRS server.

When using the module for the first time, it is possible that no host has been registered on the LRS. In that case, the module will display the message: No registered hosts on the index page. Below is an example:

Figure 3.4. Empty index page

There are two alternatives to register (e.g. declare) a new host:

Figure 3.5. Index page

As you can see on the above screenshot, the page which shows LRS essential functions, is divided in three parts.

3.2.1. Upper Part of the Interface

On each page, you will find the following links on the top right part of the page:

Figure 3.6. Webmin shortcuts

• Webmin index: To return to the Webmin index page.

• Help: contextual help.

• Module config: To change the configuration parameters which are specific to the LRS module.

• Exit: To log out or switch to another user.

You can also use the navigation bar to move between the different sections of Webmin.

Figure 3.7. Navigation bar

• Webmin will navigate you to a location where you will be able to set up the LRS web interface.

• System will navigate you to a location where you will be able to modify a certain amount of parameters, such as users, scheduler or services.

• Servers will navigate you to a location where you will be able to set up the different services running on the LRS.

• Network will navigate you to a location where you will be able to set up the LRS network interfaces.

• Hardware will navigate you to a location where you will be able to set up the LRS storage units.

• Others concentrates the LRS main functions and a few useful tools.

The topmost left part of the interface always shows the actual location inside the interface and the version number of the current module.

Figure 3.8. Main title and version

3.2.2. Navigation Tabs

The navigation tabs enable you to quickly switch between the different modules of the LRS. Depending on the context, some will not be activated.

Figure 3.9. Navigation tabs

• The first tabs level can be used to switch from one LRS module to another.

• The second level is used to switch between functions inside the top level module.

• A third level may sometimes appear to give access to sub functions.

The selected tabs have a white background and are written in bold black letters, the non-selected tabs are written in black, the tabs which can't be selected are written in gray.

Logs are used to see important events related to the LRS clients. The 'logs' tab, on the main list, can be used to get a summary of the clients' state:

Figure 3.10. Logs summary

On the summary page, the last 3 events are shown as well as the last restored image. On a single page, you can verify the restoration a clients group.

For more details, you can click on the magnifying glass in the right column.

Figure 3.11. Logs summary

Each event is associated to a colored icon. The coloing scheme is:

Usually, an orange blinking LED should always be followed by a green LED. A critical error (red), requires a manual intervention on the client to resolve the error.

Under the 'Configuration' tab, you can get access to all configuration tabs:

Figure 3.12. Configuration tabs

3.4.1. Restoration Options

An image restoration can be done in three different ways: TFTP at boot, NFS, or multicast TFTP. The restoration type can be chosen on the 'Home -> Configuration -> System backup module -> restoration type' page.

Figure 3.13. Restoration options

Each restoration type has its advantages:

• tftp at boot: Maximum compatibility. The BIOS is used to drive the HD, so all SCSI/IDE/SATA controllers are theoretically supported.

• nfs: Maximum speed (in unicast). Lower compatibility because a Linux kernel is launched for restoration.

• mtftp: Multicast restoration. You have the guarantee that a mass restoration, will be fast and will not load your network.

For the mtftp restoration, you can tune the delay before downloading each data block (a data block can be to up to 40MB). This delay is used to synchronize the data multicasting to the clients. If some clients are too slow to follow the faster clients, and if this delay is not sufficient to allow the slower clients to catch up with the faster ones, then, another multicast stream is created for them. This approach guarantees that one client which has hardware problems, cannot jeopardize the restoration of other clients.

Below you will find the time for restoring a 2 GB image (630 M compressed), using different restoration types:

Table 3.1. Restoration Time

Restoration type	PIII 500 Mhz client	P4 2.4Ghz client
tftp at boot	8 min 30 sec	6 min 20 sec
nfs	6 min 40 sec	3 min 5 sec
mtftp	10 min 10 sec	7 min

3.4.2. Traffic Shaping

Traffic shaping controls the maximum network throughput that will be used by the clients during a restoration. It is particularly useful to make sure that your network will not be saturated during a mass OS deployment.

Figure 3.14. Traffic shaping

Just specify the name of the related network interface, usually eth0, its theoretical throughput, and the allowed throughput for each of the LRSfunction:

• TFTP or multicast TFTP restoration,

• NFS restoration,

• Files deployment using the LSC,

• HTTP download on the server.

Units such as 'mbit', 'kbit' (kilo/mega bits per second) or 'kbps', 'mbps' (kilo/mega bytes per second) should be specified.

Warning, if you see an error messages in this table, it is because your kernel does not support HTB traffic shaping (QoS). Check that the following kernel options are set: CONFIG_NET_SCHED, CONFIG_NET_SCH_HTB, CONFIG_NET_SCH_SFQ, CONFIG_NET_CLS, CONFIG_NET_CLS_U32. If not, recompile your kernel (only kernel versions 2.4.20 and above support HTB). You can also check that you have the 'tc' binary usually provided by the 'iproute' package.

	technically, the traffic-shapping (TC) is setup using the following parameters: TFTP output goes in the HTP class 1:20, NFS output goes in the HTP class 1:21, TCP output to the port 22 goes in the HTP class 1:30, TCP output from the port 80 goes in the HTP class 1:31.

This form is a simple way to manually register new hosts entries in the DHCP configuration file and in the LRS server.

Most of the time, this operation is performed by the LRS and DHCP services. In tthose cases, the only task involved for the administrator is to choose a valid host name for the new computer. Nevertheless, according to the network's management policy, it is sometimes necessary to have a more accurate control over the computers recording scheme, and this form assists with that configuration.

Figure 3.15. DHCP form

When you register a new host with this form, a new entry is created in the file dhcpd.conf. Then, this information is duplicated to the LRS server (see etc/ether) which will create the directory needed to store data and configuration specific files for this host.

In the control center, the last icon in the 'Admin' column, allows to manage the clients with functions like renaming or deleting a client, and to schedule a Wake-On-Lan.

Figure 3.16. Tâches administratives

For each client, the following functions are available :

The « Wake on LAN » links allows you to remotely start a client or a group of clients.

After having choosen between, a single wake-up and a perdiodic wake-up, you should see a page similar to this one below:

Figure 3.17. WOL Scheduling

On that page, modify the 'Run on date' and 'Run at time' fields to schedule the WOL.

In the end, hit the 'Create' button. When the client wakes up, it will execute the default LRS boot menu entry.

Notes: You can assign a client to a group with the [Rename] button found on the client's menu page, and then wake a group of clients.

If you need to broadcast the WOL packets on different subnets, you can specify the broadcast addresses in the system backup configuration tab, in the 'list of broadcast addresses for WOL packets' text entry box.

This user interface supports language setting. You can choose that by selecting the Webmin configuration category, located into the Webmin tab on the Webmin main page.

Figure 3.18. Webmin Configuration

Figure 3.19. Language selection

For now, supported languages are English and French .

Command Shell

Figure 3.20. Command shell via Webmin

This module allows to do remote execution of shell commands on the server, as if executing from the console. An often used command is the 'ps' command, which lists currently running processes on the system. The 'ps' command helps to quickly know if LRS required services are active. Please review the Running Processes module located into the System tab.

File manager

Figure 3.21. File manager via Webmin (Java applet)

This module is a Java applet which, as its name describes, gives you access to the server's tree. So here you have the ability to remotely modify files, without having to handle the LRS server in place.