一 Linux运维实战之磁盘分区、格式化及挂载( 四 )


[root@Centos ~]# fdisk /dev/sdaCommand (m for help): n#创建一个新分区 Command actioneextended#键入e键创建扩展分区pprimary partition (1-4)#键入p键创建主分区e#我们要创建扩展分区哈Partition number (1-4):3#分区号我们就选3哈First cylinder (91-13054, default 91):#选择起始柱面,默认是91Using default value 91Last cylinder,cylinders orsize{K,M,G} (91-13054, default 13054):10G#选择结束柱面,这里可以用 K,M,G的方法输入Command (m for help): p#验证结果Disk /dev/sda: 107.4 GB, 107374182400 bytes 255 heads, 63 sectors/track, 13054 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00097863Device BootStart EndBlocksIdSystem /dev/sda1 * 12620480083Linux Partition 1 does not end on cylinder boundary. /dev/sda2 269152428882Linux swap / Solaris Partition 2 does not end on cylinder boundary. /dev/sda3 911396104832585Extended#可以看到创建了扩展分区哈创建逻辑分区:(扩展分区创建好了之后不能拿来直接使用哈,要想使用还需要创建逻辑分区)
Command (m for help): nCommand actionllogical (5 or over)#键入“l”创建逻辑分区(提示分区号从5开始哈)pprimary partition (1-4)lFirst cylinder (91-1396, default 91): Using default value 91 Last cylinder,cylinders orsize{K,M,G} (91-1396, default 1396):200GValue out of range.#提示超出范围了哈Last cylinder,cylinders orsize{K,M,G} (91-1396, default 1396):5GCommand (m for help): pDisk /dev/sda: 107.4 GB, 107374182400 bytes 255 heads, 63 sectors/track, 13054 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00097863Device BootStart EndBlocksIdSystem /dev/sda1 * 12620480083Linux Partition 1 does not end on cylinder boundary. /dev/sda2 269152428882Linux swap / Solaris Partition 2 does not end on cylinder boundary. /dev/sda3 911396104832585Extended/dev/sda5 91 744524603683Linux#创建了逻辑分区哈,可以看到分区号是sda5重要说明 :
(1)分区创建好了之后,用 fdisk -l 命令可以查看分区情况,但需要注意的是:虽然fidsk命令列出了所有的分区情况,不代表新分区就可以被操作系统识别了,文件系统是内核的功能(即软件能识别新分区但内核并不能识别),可以用" cat /proc/partitions "命令查看,若要内核能识别需要把分区变化情况同步到内核 。
(2) 要特别注意 :分区及格式化操作会永久地破坏目前存在于该分区上的任何数据,操作时需要特别小心(操作前对原有数据做备份)!
查看内核识别的分区信息:
[root@Centos dev]# fdisk -l #查看当前系统所有的磁盘分区情况Disk /dev/sdb: 10.7 GB, 10737418240 bytes255 heads, 63 sectors/track, 1305 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x0aeb57a8Device BootStart EndBlocksIdSystem /dev/sdb11 262210448383Linux#sdb硬盘只有一个分区哈Disk /dev/sda: 107.4 GB, 107374182400 bytes 255 heads, 63 sectors/track, 13054 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00097863Device BootStart EndBlocksIdSystem /dev/sda1* 12620480083Linux Partition 1 does not end on cylinder boundary. /dev/sda2269152428882Linux swap / Solaris Partition 2 does not end on cylinder boundary. /dev/sda3911305510412748883Linux[root@Centos dev]# cat /proc/partitions#查看内核识别的分区信息major minor#blocksname #所有的分区都能被内核识别哈,只有这样才能格式化分区操作哈;如果不能被内核识别,则我们可以让内核重新读取DPT81610485760 sdb8172104483 sdb180104857600 sda81204800 sda182524288 sda283104127488 sda3让内核重新读取硬盘分区表:RHEL5:partprobe[DEVICE]

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