Linux下磁盘分区调整（在不使用LVM的情况下）

当硬盘分区不使用LVM的时候，将不能使用lvresize等指令调整

在调整分区之前，先来了解一下当前的磁盘分区信息
1：使用Fdisk指令查看后发现sda1的分区有195309568个Sectors(扇区)
每个扇区有512字节，所以总共有99998498816字节
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root@X9DRLiF:~# fdisk -l /dev/sda
Disk /dev/sda: 223.6 GiB, 240057409536 bytes, 468862128 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x7eefe6fa

Device Boot Start End Sectors Size Id Type
/dev/sda1 2048 195311615 195309568 93.1G 83 Linux
/dev/sda2 * 453236736 468860927 15624192 7.5G 83 Linux
================================================================

2：使用resize2fs发现sda1的文件系统有24413696个blocks(块),
所以总共有99998498816字节
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root@X9DRLiF:~# resize2fs /dev/sda1
resize2fs 1.42.13 (17-May-2015)
The filesystem is already 24413696 (4k) blocks long. Nothing to do!
================================================================
用resize2fs调整如果超过了分区的界限就会有错误，可以用这个方法还原回去
resize2fs -f /dev/sda1 24413696
这里的24413696可以通过Sectors*512/4096所得

3：开始减小ext4分区，调整到200G-1M=204799M*(256)=52428544blocks
root@X9DRLiF:~# resize2fs -f /dev/sda1 52428544
resize2fs 1.42.13 (17-May-2015)
Filesystem at /dev/sda1 is mounted on /mnt/data; on-line resizing required
resize2fs: On-line shrinking not supported
这里应该先umount，如果umount不了就用fuser -k /mnt/data
===========================================================
root@X9DRLiF:~# resize2fs -f /dev/sda1 52428544
resize2fs 1.42.13 (17-May-2015)
Resizing the filesystem on /dev/sda1 to 52428544 (4k) blocks.
The filesystem on /dev/sda1 is now 52428544 (4k) blocks long.

4：然后用fdisk调整（就是d删除,n新建分区）
===================下面是调整后的样子==================
root@X9DRLiF:~# fdisk -l /dev/sda
Disk /dev/sda: 223.6 GiB, 240057409536 bytes, 468862128 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x7eefe6fa

Device Boot Start End Sectors Size Id Type
/dev/sda1 2048 419430399 419428352 200G 83 Linux
/dev/sda2 * 453236736 468860927 15624192 7.5G 83 Linux
====================================================================
这里的/dev/sda1的Sectors为419428352，除以8，刚好是block的值