Using RHEL6 as an example to introduce several Linux disaster recovery technologies and methods

With a number of Linux distributions, which are increasingly being used and are also facing the potential risk of system failure, this article will take the release version RHEL6 as an example detailing several Linux disaster recovery technologies and methodologies to ensure secure recovery of Linux systems.

Before introducing the Linux disaster recovery approach, let's take a look at the MBR, which is called the Master boot Record, which is the master boot records for the hard disk. It consists of three parts, the main boot program, http://www.aliyun.com/zixun/aggregation/10608.html "" > hard disk partition table and hard disk valid flag. The primary bootstrapper (Bootloader) occupies 446 bytes in a total of 512 bytes of the primary boot sector, the second part is a hard disk partition table, occupies 64 bytes, the number of partitions on the hard disk and the size of each partition are recorded. The third part is the hard disk valid flag, occupies 2 bytes. As shown in detail:

Figure 1. MBR

System hard disk partition table damage

Linux servers in the production environment may be damaged by viruses or accidental power outages, and usually restore the partition table of the hard disk before we need to back up the information on the partition table, we usually use the USB external device to back up the partition table of the host hard disk.

After the USB device is mounted on the host, we view the system's current disk device:

[Root@fcoe ~]# fdisk-l disk/dev/sda:43.0 GB, 42991616000 bytes 255 heads, Sectors/track, 5226 cylinders-Units = cylinders 16065 * 8225280 bytes Sector size (logical/physical): bytes/512 bytes I/o size (minimum/optimal): bytes/512 byt Es Disk identifier:0x00032735 Device Boot Start End Blocks Id system/dev/sda1 * 1 131072-Linux Partition 1 does not ' on C Ylinder boundary. /dev/sda2 147 1048576 to Linux Swap/solaris Partition 2 does not end on cylinder boundary. /dev/sda3 147 5227 40803328 disk/dev/sdb:2147 MB, 2147483648 bytes, 255, heads sectors/track Cylinders of 16065 * 8225280 bytes Sector size (logical/physical): bytes/512 bytes I/o size (minimum/optimal): 512 bytes/512 bytes Disk identifier:0x00000000 disk/dev/sdb doesn't ' t contain a valid partition table