[root@node1 ~]# fdisk -l
Disk /dev/vda: 107.4 GB, 107374182400 bytes, 209715200 sectors // 扇区个数
Units = sectors of 1 * 512 = 512 bytes // 柱面单元大小 (一个扇区作为一个柱面)
Sector size (logical/physical): 512 bytes / 512 bytes // 扇区大小
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x00040353
Device Boot Start End Blocks Id System
/dev/vda1 * 2048 1026047 512000 83 Linux
/dev/vda2 1026048 209715199 104344576 8e Linux LVM
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  | 
 
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 起始柱面  | 
 结束柱面  | 
 分区大小  | 
 分区类型  | 
 对分区类型的解析  | 
 
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 Device Boot Start End Blocks Id System  | 
 Boot  | 
 Start  | 
 End  | 
 Blocks  | 
 Id  | 
 System  | 
 
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 /dev/vda1  | 
 *  | 
 2048  | 
 1026047  | 
 512000  | 
 83  | 
 Linux  | 
 500M  | 
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 /dev/vda2  | 
 
  | 
 1026048  | 
 209715199  | 
 104344576  | 
 8e  | 
 Linux LVM  | 
 99.5G  | 
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1. 总磁盘大小: 107374182400 bytes(B) / 1024 = 104857600 KB / 1024 = 102400 MB / 1024 = 100 GB
2. 每个柱面的大小Units: 512 bytes (这里一个柱面一个扇区)
3. 扇区个数是sectors: 107374182400 bytes / 512 bytes = 209715200
4. /dev/vda1的大小是:柱面数1026047-2048 = 1023999 约等于1024000.
那么/dev/vda1的大小 = 1024000 × 512 bytes = 524288000 bytes / 1024 = 512000 K / 1024 = 500M
5. /dev/vda2的大小是:(209715199 - 1026048) × 512 bytes / 1024 / 1024 / 1024 = 99.5G
原文:http://www.cnblogs.com/lixiaolun/p/7576330.html