如何才能安全的删除逻辑卷中的硬盘或者分区？

lvm的逻辑卷可能包含一个或多个硬盘或分区。我们如何安全删除逻辑卷中的硬盘或分区？适用的情况下，我有两个小型硬盘驱动器，并且我想用一个较大的硬盘驱动器替换其中一个。首先，必须安全删除逻辑卷中的小型硬盘。以下是详细的操作过程。

1，检查分区情况

[root@iZ94zz3wqciZ data]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/xvda1             20G   15G  4.6G  76% /
tmpfs                 498M     0  498M   0% /dev/shm
/dev/mapper/myfiles-fastdfs
                       27G  9.9G   16G  39% /mnt/fastdfs

此处的27G由22G硬盘驱动器和5G硬盘驱动器组成

2，取消安装并执行硬盘检测

[root@iZ94zz3wqciZ ~]# umount /mnt/fastdfs/    //取消挂
[root@iZ94zz3wqciZ ~]# e2fsck -f /dev/mapper/myfiles-fastdfs   //磁盘检测
e2fsck 1.41.12 (17-May-2010)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/mapper/myfiles-fastdfs: 103722/1769472 files (0.1% non-contiguous), 2686136/7072768 blocks

3，重新定义逻辑卷的大小

[root@iZ94zz3wqciZ ~]# resize2fs -p /dev/mapper/myfiles-fastdfs  21G     //重定义大小
resize2fs 1.41.12 (17-May-2010)
Resizing the filesystem on /dev/mapper/myfiles-fastdfs to 5505024 (4k) blocks.
Begin pass 2 (max = 529848)
Relocating blocks             XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Begin pass 3 (max = 216)
Scanning inode table          XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Begin pass 4 (max = 66693)
Updating inode references     XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
The filesystem on /dev/mapper/myfiles-fastdfs is now 5505024 blocks long.
[root@iZ94zz3wqciZ ~]# lvreduce -L 21G /dev/mapper/myfiles-fastdfs     //重定义大小
  WARNING: Reducing active logical volume to 21.00 GiB
  THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce fastdfs? [y/n]: y
  Size of logical volume myfiles/fastdfs changed from 26.98 GiB (6907 extents) to 21.00 GiB (5376 extents).
  Logical volume fastdfs successfully resized

从27G到21G，这比要删除的5G磁盘大，即使5G磁盘数据已满，也可以将其全部删除

4，检查身体状况

[root@iZ94zz3wqciZ ~]# pvdisplay -m
  --- Physical volume ---
  PV Name               /dev/xvdb1
  VG Name               myfiles
  PV Size               21.99 GiB / not usable 4.78 MiB
  Allocatable           yes
  PE Size               4.00 MiB
  Total PE              5629
  Free PE               253
  Allocated PE          5376
  PV UUID               N2kxpi-FjET-rQ8p-MaDF-z3tH-fK3L-oW1STl
  --- Physical Segments ---
  Physical extent 0 to 5375:
    Logical volume      /dev/myfiles/fastdfs
    Logical extents     0 to 5375
  Physical extent 5376 to 5628:
    FREE
  --- Physical volume ---
  PV Name               /dev/xvdc1
  VG Name               myfiles
  PV Size               4.99 GiB / not usable 2.41 MiB
  Allocatable           yes      //激活状态，可写入
  PE Size               4.00 MiB
  Total PE              1278     //总共1278PE
  Free PE               1278     //空闲1278PE,也就是说这块硬盘是空的
  Allocated PE          0
  PV UUID               4sNW6e-XTha-7lYy-L2k8-uvWV-xxaN-wqXf0i
  --- Physical Segments ---
  Physical extent 0 to 1277:
    FREE

5，注销要删除的硬盘xvdc1

[root@iZ94zz3wqciZ ~]# pvchange -xn /dev/xvdc1    //注销xvdc1
  Physical volume "/dev/xvdc1" changed
  1 physical volume changed / 0 physical volumes not changed
[root@iZ94zz3wqciZ ~]# pvdisplay -m
  --- Physical volume ---
  PV Name               /dev/xvdb1
  VG Name               myfiles
  PV Size               21.99 GiB / not usable 4.78 MiB
  Allocatable           yes
  PE Size               4.00 MiB
  Total PE              5629
  Free PE               253
  Allocated PE          5376
  PV UUID               N2kxpi-FjET-rQ8p-MaDF-z3tH-fK3L-oW1STl
  --- Physical Segments ---
  Physical extent 0 to 5375:
    Logical volume      /dev/myfiles/fastdfs
    Logical extents     0 to 5375
  Physical extent 5376 to 5628:
    FREE
  --- Physical volume ---
  PV Name               /dev/xvdc1
  VG Name               myfiles
  PV Size               4.99 GiB / not usable 2.41 MiB
  Allocatable           NO       //不是激活状态了
  PE Size               4.00 MiB
  Total PE              1278
  Free PE               1278
  Allocated PE          0
  PV UUID               4sNW6e-XTha-7lYy-L2k8-uvWV-xxaN-wqXf0i
  --- Physical Segments ---
  Physical extent 0 to 1277:
    FREE

6。移动数据，将要删除的磁盘的数据移动到另一个磁盘

[root@iZ94zz3wqciZ ~]# pvmove -i 1 /dev/xvdc1
  No data to move for myfiles

此步骤非常重要。如果板上有数据，则不执行此步骤将导致数据丢失

7，从逻辑卷组中删除硬盘或分区，然后删除物理卷

[root@iZ94zz3wqciZ ~]# vgreduce myfiles /dev/xvdc1        //从逻辑卷组中删除
  Removed "/dev/xvdc1" from volume group "myfiles"
[root@iZ94zz3wqciZ ~]# pvremove /dev/xvdc1
  Labels on physical volume "/dev/xvdc1" successfully wiped     //删除物理卷

8，安装并查看结果

[root@iZ94zz3wqciZ ~]# mount -a
[root@iZ94zz3wqciZ ~]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/xvda1             20G   15G  4.6G  76% /
tmpfs                 498M     0  498M   0% /dev/shm
/dev/mapper/myfiles-fastdfs
                       21G  9.9G  9.8G  51% /mnt/fastdfs

在这里，您可以安全地删除硬盘或分区。

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