Raid tutorials illustrate how to do RAID

When it comes to disk arrays (RAID, Redundant Array of Independent Disks), it is now almost one of the technologies that network administrators must master, especially for small and medium enterprises, because disk arrays are widely used, it is one of the main solutions for data backup. However, many network administrators only see the introduction of relevant theoretical knowledge in various media, but do not see some actual disk array configuration methods. Therefore, they are still completely confused, but cannot start. This article will take a specific disk array configuration method as an example to introduce some basic configuration methods of the disk array, and provide some key interfaces so that you can have a rational understanding of the disk array configuration. Of course, in order to give you a more comprehensive introduction to the disk array, let's take a brief look at the theoretical knowledge about the disk array, so that we can find a theoretical basis for the actual configuration.

I. Implementation of Disk Arrays

Disk Arrays can be implemented in two ways: "software arrays" and "Hardware arrays ".

A software array is an array consisting of multiple hard disks attached to a common scsicard through the disk management function provided by the network operating system. For example, Microsoft's Windows NT/2000 Server/Server 2003 and NetVoll NetWare operating systems can provide software array functions, windows NT/2000 Server/Server 2003 provides RAID 0, RAID 1, and RAID 5. The NetWare operating system can implement the RAID 1 function. The software array can provide data redundancy, but the performance of the disk subsystem will be reduced. Some downgenerations are still relatively large, reaching about 30%.

The hardware array is implemented using a dedicated disk array card, which is the object to be introduced in this article. Currently, almost all non-entry-level servers provide disk arrays, which can be easily implemented whether integrated on the motherboard or non-integrated. The hardware array provides functions such as online resizing, dynamic modification of the array level, automatic data recovery, drive roaming, and ultra-high speed buffering. It provides performance, data protection, reliability, availability, and manageability solutions. The disk array card has a dedicated processor, such as Intel's I960 chip, HPT370A/372, and Silicon Image SIL3112A. It also has a dedicated storage device for high-speed data buffering. In this way, the server directly processes disk operations through the disk array card. Therefore, a large amount of CPU and system memory resources are not required, and the performance of the disk subsystem will not be reduced. The special processing unit of the array card is used for operations. Its performance is much higher than that of conventional non-array hard disks, and it is safer and more stable.

Ii. Several disk array Technologies

RAID technology is an industrial standard, with different vendors defining RAID levels. Currently, four RAID levels are widely recognized in the industry, RAID 0, RAID 1, RAID 0 + 1, and RAID 5.

RAID 0 is a band-based storage space without data redundancy. It features low costs, high read/write performance, and high storage space utilization, it is suitable for special applications with extremely strict speed requirements, such as audio, video signal storage, and temporary file dump. However, because there is no data redundancy, its security is greatly reduced, and damage to any hard disk that constitutes the array will lead to catastrophic data loss. In fact, this method does not provide redundancy and security protection. It only improves the disk read/write performance and the disk capacity of the entire server. Generally, it is only applicable to application environments where the number of disks is small and the number of disks is relatively short. It is unwise for general applications to configure more than four hard disks in RAID 0.

RAID 1 is a complete image of two hard disks, featuring high security, simple technology, convenient management, and good read/write performance. Because it is one-to-one, it cannot be extended by a single hard disk. To expand it, both sides of the image must expand the same capacity at the same time. This redundancy method uses only half of the disk capacity for security purposes, resulting in a large waste of data space.

RAID 0 + 1 combines the features of RAID 0 and RAID 1. An independent disk is configured as RAID 0, and the two complete RAID 0 mirrors each other. It provides excellent read/write performance and high security, but it costs a lot to build an array and has low data space utilization.

RAID 5 is the most widely used RAID technology. Each Independent hard disk is segmented by strip, and the same strip area is used for parity (exclusive or operation). The parity data is evenly distributed on each hard disk. The RAID 5 array built with n hard disks can have n-1 hard disks with high storage space utilization. Data loss on any hard disk can be calculated by verifying the data. The biggest difference between it and RAID 3 is that it verifies whether data is evenly distributed to each hard disk. RAID 5 has the advantages of data security, fast read/write speed, and high space utilization. It is widely used, but the disadvantage is that if one hard disk fails, the performance of the entire system will be greatly reduced.

RAID 1, RAID 0 + 1, RAID 5 array combined with hot swapping (also known as Hot replaceable) technology, can achieve online data recovery, that is, when any hard disk in the RAID array is damaged, if you do not need to shut down or stop the application service, you can replace the faulty hard disk, repair the system, and restore data, which is of great significance to the high-availability system.

Iii. Disk Array configuration instance

When the hard disk is connected to the array card (RAID), the operating system cannot directly view the physical hard disk, therefore, you need to create a Logical Disk (also called a container) that is set to RAID 0, 1, or 5 one by one so that the system can correctly identify it. Of course, Logic Drive, Container, or Virtual Drive all mean one thing, but they are different from each other. See the following configuration for Dell Power Edge 7x0 series and Dell PowerEdge 1650 servers.

Disk arrays are usually configured using the BIOS tool of the disk Array card, or using third-party configuration tool software to manage the Array card, such as Dell Array Manager. This article describes how to configure a disk array using the BIOS tool of the array card on the DELL server.

If the Adaptec disk array controller (PERC2, PERC2/SI, PERC3/SI, and PERC3/DI) is used on your DELL server, the following information is displayed during system boot self-check:

Dell PowerEdge Expandable RAID Controller 3/Di, BIOS V2.7-x [Build xxxx] (c) 1998-2002 Adaptec, Inc. all Rights Reserved. <Press CTRL + A for Configuration Utility! >>>

If your DELL server is configured with an AMI/LSI disk array controller (PERC2/SC, PERC2/DC, PERC3/SC, PERC3/DC, PERC4/DI, and PERC4/DC), the following information will be displayed during system boot self-check:

Dell PowerEdge Expandable RAID Controller bios x. XX Jun 26.2001 Copyright (C) american megatrends inc.
Press CTRL + M to Run Configuration Utility or Press CTRL + H for WebBios or
PowerEdge Expandable RAID Controller bios x. XX Feb 03,2003 Copyright (C) LSI Logic Corp.
Press CTRL + M to Run Configuration Utility or Press CTRL + H for WebBios

The following two cases are described respectively.

1. Create a Raid (container) on the Adaptec disk array Controller)

Follow these steps to create a container on this array card (Note: Back up the data on your server in advance. The disk array configuration process will delete all the data on the server's hard disk !) :

Step 2: when the system prompts A message during self-check (Figure 1), press Ctrl +. Go to the disk array card configuration page as shown in (figure 2.

Figure 1

Figure 2

Step 2, select Container configuration utility to go to the configuration page as shown in figure 3.

Figure 3

Step 2: Select the "Initialize Drivers" option to Initialize the new hard disk or the hard disk that needs to be re-created for the container (note: the hard disk will delete all data on the current hard disk in the initial state ), press enter to enter the page shown in Figure 4. The RAID card channel and the hard disk connected to the channel are displayed on this interface. Use the "Insert" key to select the hard disk to be initialized. (For details, see the prompt at the bottom of the interface, the same below ).

Figure 4

Step 2: Select All the disks that need to be added to the array and press the Enter key. The system key dialog box is displayed, as shown in Figure 5. The prompt box prompts that initialization will delete all data from the selected hard disk and interrupt all users who are using the hard disk.

Figure 5

Step 2: press the "Y" key to go to the Main Menu page, as shown in figure 6. After the hard disk is initialized, you can create containers at the array level (RAID1, RAID0, etc.) based on your needs. RAID5 is used as an example. Select the "Create container" option on the main menu interface.

Figure 6

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Step 2: press the Enter key to go to the configuration page as shown in Figure 7. Use the "insert" key to select the hard disk to be used to create a Container and go to the list on the right. Then press Enter. In the displayed configuration page (figure 8), press enter to select the RAID level and enter the volume label and size of the Container. The others remain unchanged by default. Click OK on the "Done" button.

Figure 7

Figure 8

Step 2: The system displays a prompt as shown in Figure 9, prompting you to tell the user before the created container is successfully cleared, this container has no redundancy function.

Figure 9

Step 2: Click press enter and return to the main menu configuration page shown in (Figure 6). Select the "Manage containers" option and click press enter to display the current container configuration status, as shown in figure 10. Select the appropriate Container and check the "Scrub" process percentage in the "Container Status" option of the Container. When it becomes "OK", the newly created Container has the redundancy function.

Figure 10

Step 2: After the disallow device is created, use the "ESC" key to exit the disk array configuration page and restart the computer.

2. Create a Logical Drive (Logical Disk) on the aim/LSI disk array Controller)

Note: Please back up data on your server in advance. The disk array configuration process will delete all data on your hard disk! The entire disk array configuration process is similar to the method described above for creating containers on the Adaptec disk array controller. The details are as follows:

Step 2: During the self-check process, when a prompt is displayed as shown in Figure 11, press the "Control + M" key combination to go to the RAID configuration interface as shown in Figure 12.

Figure 11

Figure 12

Step 2: press any key to continue and go to the Management Menu configuration page as shown in Figure 13. Select the "Configure" option and press the Enter key to bring up the Sub-menu, as shown in figure 14.

Figure 13

Figure 14

Step 2: If you need to reconfigure a RAID, select "New Configuration". If a Logical Disk already exists, select "View/Add Configuration" and press the Enter key. Here, we will introduce how to create a disk array. Select "New Configuration. Press enter to bring up a small dialog box, as shown in Figure 15.

Figure 15

Step 2: Select "YES" and press the Enter key to go to the configuration page as shown in Figure 16. Use the Space key to select the hard disk for which you want to create a logical disk. When the last hard disk in the Logical Disk is selected, press the Enter key.

Figure 16

Step 2: If the array card type on your server is PERC4 DI/DC, after you press enter, the configuration page shown in (figure 17) is displayed. Otherwise, go to step 2.

Figure 17

In step 2, press the Space key to select the array concatenation information, for example, Span-1 (concatenation-1), which appears in the array box. You can create multiple arrays and then select to interconnect them.

Step 2: Press "F10" to configure the Logical Disk. Select the appropriate RAID type, and accept the default values for others. Select "Accept" and press the Enter key to confirm. The final configuration information prompt box shown in (Figure 18) is displayed.

Figure 18

Step 2: The created Logical Disk must be initialized before it can be used. Press the ESC key to return to the main menu shown in (Figure 13), select the "Initialize" option, and press the Enter key to go to the initialization logic disk interface shown in (figure 19.

Figure 19

Step 2: select the Logical Disk to be initialized and press a space to bring up a dialog box, as shown in Figure 20. Select "YES" and press the Enter key to bring up the initialization process. (Note that you need to back up the original data in the damaged disk before initializing the disk ).

Figure 20

 

Step 2. After Initialization is complete, press any key to continue and restart the system. The RAID configuration is complete.