How to implement dual-boot for Linux and AIX on the server

Introduction

On the IBM eServer server that supports logical partitions, Linux and AIX should be run in different separate partitions. However, not all configurations support logical partitions, and sometimes all resources need to be available on the hardware. In these cases, the dual-boot Linux and AIX operating systems may be an effective way to provide each platform based on your needs. Unlike Linux for x86 servers, there is no public Boot Loader for dual-boot operating systems. Fortunately, OpenFirmware allows multiple boot devices to enable Dual Boot. This tool eliminates the need to manually switch the drive back and forth on the machine. Manual disk swap may cause users and operating systems to wonder which disk is the primary disk. This document assumes that you are familiar with Linux for POWER.™And AIX installation.

Configure Dual Boot from OpenFirmware

It is critical to use the OpenFirmware interface to select the boot device. Do not try to change the boot sequence by physically disconnecting the drive. Disconnecting the drive may lead to disorder in the drive sequence, then cause failure to boot the disk, and may cause data loss.

The boot device configuration menu is located in the OpenFirmware menu system. After the machine is enabled, press 1 when "E1F1 to reach OpenFirmware" is displayed on the LCD status panel. In the main menu, perform the following steps:

Select option 7, that is, Select Boot Options.

Select option 2, that is, Select Boot Devices. This menu allows you to set the preferred sequence of Boot devices, and will prepare option 3 in the Select Boot Options menu of the Multiboot menu for future use.

Select option 5 from the Select Device Type menu, that is, Hard Drive.

Select option 1 from the next menu, that is, SCSI. This menu allows you to set which disk to boot first by default. This menu also allows you to set the order of other disks in the Multiboot menu.

Select Task from the next menu, and then select M to return to the main menu.

You can repeat these steps if necessary to correctly set the boot sequence of the boot disk.

To Boot a specific disk, you can return to the Select Boot Options menu and Select option 3, that is, the Multiboot menu. This menu allows you to set OpenFirmware so that it is always paused on the Multiboot menu during boot so that you do not have to press the 1 key ). It also allows you to select disks that have been arranged using the preceding method.

Configure the boot device in the operating system

In Linux, you can use the nvsetenv tool in/sbin to configure the boot device used in the next boot. The tool must be used as root.

With a simple script, you can set the candidate reboot command to allow the machine to reboot in Linux or AIX. The format used by/sbin/nvsetenv pilot device entries is the same as that provided in OpenFirmware. You can view the device name in OpenFirmware and copy the information to the command line issued by/sbin/nvsetenv. For example:

/sbin/nvsetenv boot-device=/pci@400000000111/pci@2, 2/scsi@1/sd@1,0:1,ppcbootinfo.txt /pci@400000000110/pci@2,4/scsi@1/sd@8,0

Note: All code is a whole line, with only one space behind the txt.

In AIX, you can use the bootlist command to perform the same operation. See the nvsetenv and bootlist manuals for auxiliary instructions on each tool.

Conclusion

Do not try to reorder boot devices by physically switching disks. You can use the console interface of OpenFirmware or a tool provided in Linux or AIX to change the sequence of boot devices. This protects your data and makes system maintenance easier.

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Create Qpopper

Once Qpopper is installed, You need to enable the Service. If you are using inetd or xinetd, you can simply restart the inetd or xinetd background program by executing kill-HUP. You can run ps aux | grep inet to determine the process ID (PID ).

If you have installed Qpopper in standalone mode, you need to place the parameter-S in the/etc/init. d/pop3 file to execute the script you have created. For example, the-S tag tells Qpopper to run in server mode, which can improve the input/output performance of the server. If it is not in server mode, Qpopper copies the email file based on the priority access principle and copies it back after corresponding adjustments, such as deleting an email. In server mode, Qpopper scans the queue rather than copies and processes them directly in users' tasks. This is especially important for POP3 servers that need to support a large number of users.

When running a POP3 server, Table 1 lists all the command options you can use. For example, you can remotely log on to your server from port 110 and manually delete large information. A comprehensive understanding of these options will help you quickly solve your email faults.

After this command, enter your user id, such as USER webmaster.

PASS: enter the password for this account.

The QUIT command ends the current task and deletes the marked emails.

The list command can be used to LIST the information and size.

RETR restores a specific email with an information number.

The DELE Command deletes a specific email with an information number.

TOP displays the first N rows of a specific email (TOP <# lines> ).

Qpopper relies on the standard system verification mechanism being applied through/etc/passwd and/etc/shadow. Therefore, to allow users to use the POP3 service, it is necessary to add the service to the local system. Since you may have run an email proxy such as Sendmail, this is actually done.

Discover and solve Qpopper faults

During the first running of any service you install, some problems may occur. A good solution is that the server can respond to POP3 requests logging on to port 110. You can try to log on from a local or remote site. You can see the command line examples in these experiments.

If a large number of users connect to your server to obtain emails, you may need to change the maximum wait value to increase the inetd timeout value. You can do this:

pop3 stream tcp nowait.400 root /usr/local/lib/popper qpopper -s

When a large number of tasks are running at the same time, this can prevent Qpopper from entering an endless loop. When you start logging in, your log file starts to record the service, and you can change the timeout value I mentioned above.

Another problem is that emails are often locked on large websites. When a client opens a POP3 task to the server, the file will be created when the email is locked. It blocks connections to other modified mailboxes. Sometimes, a user is disconnected abnormally, and Qpopper cannot delete the temporary file queue established at the beginning of the task. This often appears in the/var/spool directory in the form of. user. pop. The server usually detects out-of-date email locks and deletes them. However, in rare cases, administrators may need to manually delete these files to allow re-access to the POP3 server.

Summary

To provide users with the full email function, it is an important step to add the POP3 service to your Sendmail server. Through Qpopper, this task becomes quite simple. Download, install, restart, and run quickly. It can also run with other standard SMTP servers.