一、目的
在使用CentOS6.3版本linux系统的时候,发现根目录(/)的空间不是很充足,而其他目录空间有很大的空闲,所以本文主要是针对现在已有的空间进行调整。首先,先来查看一下系统的空间分配情况:
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[root@CentOS-78 /]# df -h
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Filesystem Size Used Avail Use% Mounted on
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/dev/mapper/vg_centos-lv_root
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50G 14G 34G 30% /
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tmpfs 1.9G 0 1.9G 0% /dev/shm
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/dev/sda1 485M 37M 423M 8% /boot
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/dev/mapper/vg_centos-lv_home
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404G 670M 382G 1% /home
下面的详细步骤部分将从vg_centos-lv_home分区下取出100G的空间添加到/vg_centos-lv_root分区上去。
二、详细步骤
1、卸载vg_centos-lv_home分区
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[root@CentOS-78 /]# umount /home
此时在用df命令查看将会发现/home目录已经看不见了,如下所示:
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[root@CentOS-78 /]# df -h
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Filesystem Size Used Avail Use% Mounted on
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/dev/mapper/vg_centos-lv_root
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50G 14G 34G 30% /
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tmpfs 1.9G 0 1.9G 0% /dev/shm
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/dev/sda1 485M 37M 423M 8% /boot
2、从新设定vg_home-lv_home的大小
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[root@CentOS-78 /]# resize2fs -p /dev/mapper/vg_centos-lv_home 282G
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resize2fs 1.41.12 (17-May-2010)
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Please run 'e2fsck -f /dev/mapper/vg_centos-lv_home' first.
这一步设定vg_home-lv_home大小没有成功,系统提示我们先运行下面的命令,操作如下:
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[root@CentOS-78 /]# e2fsck -f /dev/mapper/vg_centos-lv_home
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e2fsck 1.41.12 (17-May-2010)
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Pass 1: Checking inodes, blocks, and sizes
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Pass 2: Checking directory structure
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Pass 3: Checking directory connectivity
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Pass 4: Checking reference counts
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Pass 5: Checking group summary information
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/dev/mapper/vg_centos-lv_home: 1386/26836992 files (0.9% non-contiguous), 1855856/107344896 blocks
从新设定vg_home-lv_home的大小:
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[root@CentOS-78 /]# resize2fs -p /dev/mapper/vg_centos-lv_home 282G
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resize2fs 1.41.12 (17-May-2010)
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Resizing the filesystem on /dev/mapper/vg_centos-lv_home to 73924608 (4k) blocks.
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Begin pass 2 (max = 43)
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Relocating blocks XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
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Begin pass 3 (max = 3276)
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Scanning inode table XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
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Begin pass 4 (max = 266)
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Updating inode references XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
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The filesystem on /dev/mapper/vg_centos-lv_home is now 73924608 blocks long.
检查是否成功:
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[root@CentOS-78 /]# mount /home
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[root@CentOS-78 /]#
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[root@CentOS-78 /]# df -h
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Filesystem Size Used Avail Use% Mounted on
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/dev/mapper/vg_centos-lv_root
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50G 14G 34G 30% /
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tmpfs 1.9G 0 1.9G 0% /dev/shm
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/dev/sda1 485M 37M 423M 8% /boot
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/dev/mapper/vg_centos-lv_home
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278G 663M 263G 1% /home
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[root@CentOS-78 /]#
3、将lv_home逻辑分区减小到指定大小
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[root@CentOS-78 /]# lvreduce -L 282G /dev/mapper/vg_centos-lv_home
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WARNING: Reducing active and open logical volume to 282.00 GiB
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THIS MAY DESTROY YOUR DATA (filesystem etc.)
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Do you really want to reduce lv_home? [y/n]: y
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Reducing logical volume lv_home to 282.00 GiB
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Logical volume lv_home successfully resized
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[root@CentOS-78 /]#
我认为这个命令是将已经减少的100G空间拿到系统公共的区域,可以被其他分区加载和利用。
查询卷组的信息:
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[root@CentOS-78 /]# vgdisplay
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--- Volume group ---
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VG Name vg_centos
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System ID
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Format lvm2
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Metadata Areas 1
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Metadata Sequence No 5
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VG Access read/write
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VG Status resizable
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MAX LV 0
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Cur LV 3
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Open LV 3
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Max PV 0
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Cur PV 1
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Act PV 1
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VG Size 465.27 GiB
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PE Size 4.00 MiB
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Total PE 119109
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Alloc PE / Size 86472 / 337.78 GiB
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Free PE / Size 32637 / 127.49 GiB
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VG UUID 1k4ooN-RFV9-uyf1-uMYf-aERG-YaGs-ZNoSD6
Free PE / Size指定的应该是现在可在分配的空间。
4、增加vg_centos-lv_root分区的大小
将可用的空间添加到vg_centos-lv_root分区上面:
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[root@CentOS-78 /]# lvextend -L +127.40G /dev/mapper/vg_centos-lv_root
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Rounding up size to full physical extent 127.40 GiB
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Extending logical volume lv_root to 177.40 GiB
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Logical volume lv_root successfully resized
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[root@CentOS-78 /]#
从新设定该分区的大小:
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[root@CentOS-78 /]# resize2fs -p /dev/mapper/vg_centos-lv_root
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resize2fs 1.41.12 (17-May-2010)
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Filesystem at /dev/mapper/vg_centos-lv_root is mounted on /; on-line resizing required
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old desc_blocks = 4, new_desc_blocks = 12
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Performing an on-line resize of /dev/mapper/vg_centos-lv_root to 46504960 (4k) blocks.
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The filesystem on /dev/mapper/vg_centos-lv_root is now 46504960 blocks long.
5、再次查看分区大小
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[root@CentOS-78 /]# df -h
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Filesystem Size Used Avail Use% Mounted on
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/dev/mapper/vg_centos-lv_root
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175G 14G 153G 9% /
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tmpfs 1.9G 0 1.9G 0% /dev/shm
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/dev/sda1 485M 37M 423M 8% /boot
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/dev/mapper/vg_centos-lv_home
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278G 663M 263G 1% /home
我们发现vg_centos-lv_root分区的空间已经增加了125G,之所以比lv_home减少的空间要多25G主要是由于我们把系统所有的可用的空间都加在了lv_root分区。
三、所遇到的问题
1、在卸载/home目录的时候失败
可先执行如下fuser命令,然后再umount即可:
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[root@CentOS-78 /]# fuser -m /home
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[root@CentOS-78 /]#
2、设定完lv_home的大小,再次mount该分区时,发现用df命令无法看到给分区,此时只要在mount一次即可
3、在设定lv_root的大小时,不要把Free PE / Size的空间全部都用上,这很可能会出现Free PE空间不足的现象,建议保留一点Free PE的空间。
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