相较于扩容逻辑卷，在对逻辑卷进行缩容操作时，其丢失数据的风险更大。所以在生产环境中执行相应操作时，一定要提前备份好数据。另外linux系统规定，在对
LVM逻辑卷进行缩容操作之前，要先检查文件系统的完整性（为了数据安全）。在执行缩容之前先把文件系统卸载。
1、下载逻辑卷设备的挂载
[root@linuxprobe dev]# df -h ## 查看挂载 Filesystem Size Used Avail Use% Mounted on /dev/mapper/rhel-root 18G 2.9G 15G 17% / devtmpfs 985M 0 985M 0% /dev tmpfs 994M 80K 994M 1% /dev/shm tmpfs 994M 8.9M 986M 1% /run tmpfs 994M 0 994M 0% /sys/fs/cgroup /dev/sda1 497M 119M 379M 24% /boot /dev/sr0 3.5G 3.5G 0 100% /run/media/root/RHEL-7.0 Server.x86_64 /dev/mapper/vgtest1-lvtest1 287M 2.1M 266M 1% /linuxprobe [root@linuxprobe dev]# umount /linuxprobe/ ## 卸载 [root@linuxprobe dev]# df -h ## 查看挂载 Filesystem Size Used Avail Use% Mounted on /dev/mapper/rhel-root 18G 2.9G 15G 17% / devtmpfs 985M 0 985M 0% /dev tmpfs 994M 80K 994M 1% /dev/shm tmpfs 994M 8.9M 986M 1% /run tmpfs 994M 0 994M 0% /sys/fs/cgroup /dev/sda1 497M 119M 379M 24% /boot /dev/sr0 3.5G 3.5G 0 100% /run/media/root/RHEL-7.0 Server.x86_64
2、检查文件系统的完整性
[root@linuxprobe dev]# e2fsck -f /dev/vgtest1/lvtest1 e2fsck 1.42.9 (28-Dec-2013) 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/vgtest1/lvtest1: 11/76000 files (0.0% non-contiguous), 15759/307200 blocks
3、把逻辑卷lvtest1的容量缩小到100MB
[root@linuxprobe dev]# lvdisplay ## 查看当前逻辑卷大小 --- Logical volume --- LV Path /dev/vgtest1/lvtest1 LV Name lvtest1 VG Name vgtest1 LV UUID oTCZoZ-CymC-Ce3k-JFGo-95ne-6lho-Y6a0Ll LV Write Access read/write LV Creation host, time linuxprobe.com, 2020-10-29 16:30:51 +0800 LV Status available # open 0 LV Size 300.00 MiB Current LE 75 Segments 1 Allocation inherit ……………… [root@linuxprobe dev]# resize2fs /dev/vgtest1/lvtest1 100M ## 重置大小 resize2fs 1.42.9 (28-Dec-2013) Resizing the filesystem on /dev/vgtest1/lvtest1 to 102400 (1k) blocks. The filesystem on /dev/vgtest1/lvtest1 is now 102400 blocks long. [root@linuxprobe dev]# lvreduce -L 100M /dev/vgtest1/lvtest1 ## 重置逻辑卷大小 WARNING: Reducing active logical volume to 100.00 MiB THIS MAY DESTROY YOUR DATA (filesystem etc.) Do you really want to reduce lvtest1? [y/n]: y Reducing logical volume lvtest1 to 100.00 MiB
4、重新挂载
[root@linuxprobe dev]# df -h ## 查看挂载 Filesystem Size Used Avail Use% Mounted on /dev/mapper/rhel-root 18G 2.9G 15G 17% / devtmpfs 985M 0 985M 0% /dev tmpfs 994M 80K 994M 1% /dev/shm tmpfs 994M 8.9M 986M 1% /run tmpfs 994M 0 994M 0% /sys/fs/cgroup /dev/sda1 497M 119M 379M 24% /boot /dev/sr0 3.5G 3.5G 0 100% /run/media/root/RHEL-7.0 Server.x86_64 [root@linuxprobe dev]# mount -a ## 挂载 [root@linuxprobe dev]# df -h ## 查看挂载 Filesystem Size Used Avail Use% Mounted on /dev/mapper/rhel-root 18G 2.9G 15G 17% / devtmpfs 985M 0 985M 0% /dev tmpfs 994M 80K 994M 1% /dev/shm tmpfs 994M 8.9M 986M 1% /run tmpfs 994M 0 994M 0% /sys/fs/cgroup /dev/sda1 497M 119M 379M 24% /boot /dev/sr0 3.5G 3.5G 0 100% /run/media/root/RHEL-7.0 Server.x86_64 /dev/mapper/vgtest1-lvtest1 93M 1.6M 85M 2% /linuxprobe [root@linuxprobe dev]# lvdisplay ## 查看详细信息 --- Logical volume --- LV Path /dev/vgtest1/lvtest1 LV Name lvtest1 VG Name vgtest1 LV UUID oTCZoZ-CymC-Ce3k-JFGo-95ne-6lho-Y6a0Ll LV Write Access read/write LV Creation host, time linuxprobe.com, 2020-10-29 16:30:51 +0800 LV Status available # open 1 LV Size 100.00 MiB Current LE 25
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