调整 LVM 大小而不丢失数据

Question

我有带有 LVM 的 Cloud Linux Serwer，带有两个磁盘 (40 + 50)。今天，我不需要第二个驱动器，我想通过保留 LVM 来拔掉它以供将来使用。

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# vgdisplay\n  --- Volume group ---\n  VG Name               system\n  System ID\n  Format                lvm2\n  Metadata Areas        2\n  Metadata Sequence No  20\n  VG Access             read/write\n  VG Status             resizable\n  MAX LV                0\n  Cur LV                2\n  Open LV               2\n  Max PV                0\n  Cur PV                2\n  Act PV                2\n  VG Size               89.75 GiB\n  PE Size               4.00 MiB\n  Total PE              22977\n  Alloc PE / Size       22977 / 89.75 GiB\n  Free  PE / Size       0 / 0\n  VG UUID               QkkfoN-Ftor-suCL-VF4J-huV2-lhWp-9K5cMx\n\n# df -Th\nFilesystem              Type      Size  Used Avail Use% Mounted on\n/dev/mapper/system-root ext4       88G   21G   63G  25% /\nnone                    tmpfs     4.0K     0  4.0K   0% /sys/fs/cgroup\nudev                    devtmpfs  485M  4.0K  485M   1% /dev\ntmpfs                   tmpfs     100M  412K   99M   1% /run\nnone                    tmpfs     5.0M     0  5.0M   0% /run/lock\nnone                    tmpfs     496M     0  496M   0% /run/shm\nnone                    tmpfs     100M     0  100M   0% /run/user\n/dev/vda1               ext2      236M   98M  127M  44% /boot\n\n# lsblk\nNAME                     MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT\nsr0                       11:0    1  1024M  0 rom\nvda                      253:0    0    40G  0 disk\n\xe2\x94\x9c\xe2\x94\x80vda1                   253:1    0   243M  0 part /boot\n\xe2\x94\x9c\xe2\x94\x80vda2                   253:2    0     1K  0 part\n\xe2\x94\x94\xe2\x94\x80vda5                   253:5    0  39.8G  0 part\n  \xe2\x94\x9c\xe2\x94\x80system-root (dm-0)   252:0    0  88.8G  0 lvm  /\n  \xe2\x94\x94\xe2\x94\x80system-swap_1 (dm-1) 252:1    0     1G  0 lvm  [SWAP]\nvdb                      253:16   0    50G  0 disk\n\xe2\x94\x94\xe2\x94\x80vdb1                   253:17   0    50G  0 part\n  \xe2\x94\x94\xe2\x94\x80system-root (dm-0)   252:0    0  88.8G  0 lvm  /\n\n# pvdisplay --maps\n  --- Physical volume ---\n  PV Name               /dev/vda5\n  VG Name               system\n  PV Size               39.76 GiB / not usable 2.00 MiB\n  Allocatable           yes (but full)\n  PE Size               4.00 MiB\n  Total PE              10178\n  Free PE               0\n  Allocated PE          10178\n  PV UUID               aUQpTn-xi1T-ygwu-emIh-I2CT-w2tp-cRUNjl\n\n  --- Physical Segments ---\n  Physical extent 0 to 9921:\n    Logical volume      /dev/system/root\n    Logical extents     0 to 9921\n  Physical extent 9922 to 10177:\n    Logical volume      /dev/system/swap_1\n    Logical extents     0 to 255\n\n  --- Physical volume ---\n  PV Name               /dev/vdb1\n  VG Name               system\n  PV Size               50.00 GiB / not usable 2.00 MiB\n  Allocatable           yes (but full)\n  PE Size               4.00 MiB\n  Total PE              12799\n  Free PE               0\n  Allocated PE          12799\n  PV UUID               5IbHi7-bS0j-ZDEQ-pPfY-BGW4-PAk0-pEV8VH\n\n  --- Physical Segments ---\n  Physical extent 0 to 12798:\n    Logical volume      /dev/system/root\n    Logical extents     9922 to 22720\n

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现在如果他想使用命令 lvresize

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# lvresize --size -50G /dev/mapper/system-root\n  WARNING: Reducing active and open logical volume to 38.75 GiB\n  THIS MAY DESTROY YOUR DATA (filesystem etc.)\n

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系统警告我数据丢失。如何通过断开磁盘来减少空间而不丢失数据？

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Answer 1

您必须先缩小 ext4 文件系统才能减少逻辑卷大小。您必须卸载根分区，因此为了缩小文件系统，您必须使用 USB/DVD Linux iso 启动服务器并执行救援模式。

示例： https: //www.thegeekdiary.com/centos-rhel-how-to-shrink-lvm-root-file-system/