Hot swapping and online identification of SCSI hard disks in Linux

Linux implements SCSI hard drive hot swapping and online identification-Linux Enterprise Application-Linux server application information. The following is a detailed description. Today, we need to add a hard disk (SCSI) to a server, but the server cannot be shut down, so we thought of hot swapping. We can let the system identify the new hard disk with no downtime, the procedure is as follows:

Step 1: Insert the new hard disk to the machine;

Step 2: run the command as the root user:

Echo "scsi add-single-device x y z u">/proc/scsi

Where:
X is the SCSI controller Number of the hard disk (usually a SCSI controller, so it is 0 );
Y is the serial number of the SCSI channel where the hard disk is located (generally, the serial number of the single channel is 0, and the multi-channel depends on the Channel );
Z is the scsi id of the hard disk (which can be determined by the hard disk slot Inserted );
U is the lun Number of the hard disk (both are 0 by default)

Since I inserted the third hard disk, the command I run is:

Echo "scsi add-single-device 0 0 2 0">/proc/scsi

If the x y z parameter is incorrect, the system cannot identify the added hard disk. You can check the content of the/proc/scsi file to determine whether the added disk is successful. After the file is added, a device is added to the file. This file contains detailed information about all SCSI devices identified by the system, including the vendor, model, and media access type.

After running the above command, I checked the file/proc/scsi and found that there was one more device (the last one ):

Attached devices:
Host: scsi0 Channel: 00 Id: 00 Lun: 00
Vendor: MAXTOR Model: ATLASU320_18_SCA Rev: B120
Type: Direct-Access ansi scsi revision: 03
Host: scsi0 Channel: 00 Id: 01 Lun: 00
Vendor: IBM Model: IC35L036UCDY10-0 Rev: S28F
Type: Direct-Access ansi scsi revision: 03
Host: scsi0 Channel: 00 Id: 06 Lun: 00
Vendor: ESG-SHV Model: SCA hsystolic M17 Rev: 1.15
Type: Processor ansi scsi revision: 02
Host: scsi0 Channel: 00 Id: 02 Lun: 00
Vendor: IBM Model: IC35L146UCDY10-0 Rev: S26B
Type: Direct-Access ansi scsi revision: 03

Then look at the/proc/partition file and find that the hard disk has been identified! Next, you can partition, format, and use the partition tool. Because you do not need to reboot the system when using the parted partition tool, you do not need to restart the system during the entire hard disk adding process.

To remove a hard disk, perform the following operations:

Step 1: run the command as the root user:

Echo "scsi remove-single-device x y z u">/proc/scsi

The definition of x y z u is the same as above.

Step 2: physically disconnect the hard disk.