源文档地址:https://www.2daygeek.com/create-lvm-storage-logical-volume-manager-in-linux/
1. 创建PV创建前/dev/sdb不能分区,如果已经分区,使用fdisk /dev/sdb 删除分区 [root@O-Friday ~]# pvcreate /dev/sdb /dev/sdc WARNING: dos signature detected on /dev/sdb at offset 510. Wipe it? [y/n]: y Wiping dos signature on /dev/sdb. WARNING: dos signature detected on /dev/sdc at offset 510. Wipe it? [y/n]: y Wiping dos signature on /dev/sdc. Physical volume "/dev/sdb" successfully created. Physical volume "/dev/sdc" successfully created. [root@O-Friday ~]# pvdisplay --- Physical volume --- PV Name /dev/sda2 VG Name openeuler PV Size <98.00 GiB / not usable 3.00 MiB Allocatable yes (but full) PE Size 4.00 MiB Total PE 25087 Free PE 0 Allocated PE 25087 PV UUID Yv3d0c-OjcH-8s93-MsfZ-1JUu-XwU3-NYyPYD "/dev/sdb" is a new physical volume of "10.00 GiB" --- NEW Physical volume --- PV Name /dev/sdb VG Name PV Size 10.00 GiB Allocatable NO PE Size 0 Total PE 0 Free PE 0 Allocated PE 0 PV UUID AxdYk0-Giiv-kF4Z-QOIj-yA6j-Rsf0-BI7S2o "/dev/sdc" is a new physical volume of "10.00 GiB" --- NEW Physical volume --- PV Name /dev/sdc VG Name PV Size 10.00 GiB Allocatable NO PE Size 0 Total PE 0 Free PE 0 Allocated PE 0 PV UUID Nz06rK-h4FH-Jy2v-hXuE-hiws-6SRW-PSMQez2. 创建VGvgname = openeuler是系统安装时自动创建 [root@O-Friday ~]# vgcreate vg01 /dev/sdb /dev/sdc Volume group "vg01" successfully created [root@O-Friday ~]# vgdisplay --- Volume group --- VG Name vg01 System ID Format lvm2 Metadata Areas 2 Metadata Sequence No 1 VG Access read/write VG Status resizable MAX LV 0 Cur LV 0 Open LV 0 Max PV 0 Cur PV 2 Act PV 2 VG Size 19.99 GiB PE Size 4.00 MiB Total PE 5118 Alloc PE / Size 0 / 0 Free PE / Size 5118 / 19.99 GiB VG UUID oAbeGg-j8U2-kCuO-tcmW-HQWv-MqbT-kQdipr --- Volume group --- VG Name openeuler System ID Format lvm2 Metadata Areas 1 Metadata Sequence No 3 VG Access read/write VG Status resizable MAX LV 0 Cur LV 2 Open LV 2 Max PV 0 Cur PV 1 Act PV 1 VG Size <98.00 GiB PE Size 4.00 MiB Total PE 25087 Alloc PE / Size 25087 / <98.00 GiB Free PE / Size 0 / 0 VG UUID I7kRIn-4XeX-0agf-OxRq-ehSi-hqJf-nvkmtU 3. 查看vg [root@O-Friday ~]# vgs vg01 VG #PV #LV #SN Attr VSize VFree vg01 2 0 0 wz--n- 19.99g 19.99g4. 扩展VG [root@O-Friday ~]# vgextend vg01 /dev/sdd WARNING: dos signature detected on /dev/sdd at offset 510. Wipe it? [y/n]: y Wiping dos signature on /dev/sdd. Physical volume "/dev/sdd" successfully created. Volume group "vg01" successfully extended 5. 创建LV/swap 与 /root为安装系统时自动创建 [root@O-Friday ~]# lvcreate -n lv001 -L 15G vg01 Logical volume "lv001" created. [root@O-Friday ~]# lvdisplay --- Logical volume --- LV Path /dev/vg01/lv001 LV Name lv001 VG Name vg01 LV UUID 0TdOKB-PDI3-LWDv-X2nb-lBVV-kfLJ-jVOVBy LV Write Access read/write LV Creation host, time O-Friday, 2023-03-15 14:24:07 +0800 LV Status available # open 0 LV Size 15.00 GiB Current LE 3840 Segments 2 Allocation inherit Read ahead sectors auto - currently set to 8192 Block device 253:2 --- Logical volume --- LV Path /dev/openeuler/swap LV Name swap VG Name openeuler LV UUID xNBLth-zrQf-HY8L-fSrA-jrrU-qERF-xfDafa LV Write Access read/write LV Creation host, time O-Friday, 2023-03-05 10:52:53 +0800 LV Status available # open 2 LV Size 6.00 GiB Current LE 1536 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 8192 Block device 253:1 --- Logical volume --- LV Path /dev/openeuler/root LV Name root VG Name openeuler LV UUID i3ZktA-EN9t-HJB3-y1Ok-Or1X-z0uq-3ixcbG LV Write Access read/write LV Creation host, time O-Friday, 2023-03-05 10:52:54 +0800 LV Status available # open 1 LV Size <92.00 GiB Current LE 23551 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 8192 Block device 253:0 6. 查看lv [root@O-Friday ~]# lvs /dev/vg01/lv001 LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert lv001 vg01 -wi-a----- 15.00g 7. 使用PE size 创建lv 15GB = 15360MB / 4MB (PE Size) = 3840 PEs lvcreate -n lv001 -l 3840 vg018. 使用比例创建 lvcreate -n lv001 -l 100%FREE vg01 9. 创建File system mkfs -t ext4 /dev/vg01/lv001 mkfs -t xfs /dev/vg01/lv001 两种文件系统格式创建,下面使用ext4 [root@O-Friday ~]# lvs /dev/vg01/lv001 LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert lv001 vg01 -wi-a----- 15.00g [root@O-Friday ~]# mkfs -t ext4 /dev/vg01/lv001 mke2fs 1.46.4 (18-Aug-2021) Creating filesystem with 3932160 4k blocks and 983040 inodes Filesystem UUID: 81d59fcc-ebac-430e-8eca-c36ed3155160 Superblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208 Allocating group tables: done Writing inode tables: done Creating journal (16384 blocks): done Writing superblocks and filesystem accounting information: done 10. 从lvm中移除物理卷 要移除的物理卷,used必须为0,如果要移除/dev/sdd首先通过pvmove将数据移动到其他物理卷 如果没有空闲的空间来移动数据,需要添加新的物理卷后,再移除原物理卷 [root@O-Friday ~]# pvs -o+pv_used PV VG Fmt Attr PSize PFree Used /dev/sda2 openeuler lvm2 a-- <98.00g 0 <98.00g /dev/sdb vg01 lvm2 a-- <10.00g 0 <10.00g /dev/sdc vg01 lvm2 a-- <10.00g <10.00g 0 /dev/sdd vg01 lvm2 a-- <10.00g 4.99g 5.00g [root@O-Friday ~]# pvmove /dev/sdd /dev/sdd: Moved: 1.72% /dev/sdd: Moved: 100.00% [root@O-Friday ~]# pvs -o+pv_used PV VG Fmt Attr PSize PFree Used /dev/sda2 openeuler lvm2 a-- <98.00g 0 <98.00g /dev/sdb vg01 lvm2 a-- <10.00g 0 <10.00g /dev/sdc vg01 lvm2 a-- <10.00g 4.99g 5.00g /dev/sdd vg01 lvm2 a-- <10.00g <10.00g 0 [root@O-Friday ~]# pvremove /dev/sdd PV /dev/sdd is used by VG vg01 so please use vgreduce first. (If you are certain you need pvremove, then confirm by using --force twice.) /dev/sdd: physical volume label not removed. 此时依然不能移除,因为pv在vg中已经使用,需要先用vgreduce删除 [root@O-Friday ~]# vgreduce vg01 /dev/sdd Removed "/dev/sdd" from volume group "vg01" [root@O-Friday ~]# pvremove /dev/sdd Labels on physical volume "/dev/sdd" successfully wiped. 11. 如何删除逻辑卷 如果已经挂载分区先执行umount /data 如果已经/etc/fstab设置了自动挂载, 要先删除 Disable the “lv001” logical volume 执行后查看lv status 已经是 not available状态 [root@O-Friday ~]# lvchange -an /dev/vg01/lv001 [root@O-Friday ~]# lvdisplay --- Logical volume --- LV Path /dev/vg01/lv001 LV Name lv001 VG Name vg01 LV UUID 0TdOKB-PDI3-LWDv-X2nb-lBVV-kfLJ-jVOVBy LV Write Access read/write LV Creation host, time O-Friday, 2023-03-15 14:24:07 +0800 LV Status NOT available LV Size 15.00 GiB Current LE 3840 Segments 2 Allocation inherit Read ahead sectors auto --- Logical volume --- LV Path /dev/openeuler/swap LV Name swap VG Name openeuler LV UUID xNBLth-zrQf-HY8L-fSrA-jrrU-qERF-xfDafa LV Write Access read/write LV Creation host, time O-Friday, 2023-03-05 10:52:53 +0800 LV Status available # open 2 LV Size 6.00 GiB Current LE 1536 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 8192 Block device 253:1 --- Logical volume --- LV Path /dev/openeuler/root LV Name root VG Name openeuler LV UUID i3ZktA-EN9t-HJB3-y1Ok-Or1X-z0uq-3ixcbG LV Write Access read/write LV Creation host, time O-Friday, 2023-03-05 10:52:54 +0800 LV Status available # open 1 LV Size <92.00 GiB Current LE 23551 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 8192 Block device 253:0 12. 删除VG If there are no logical volumes associated with the volume group(VG) and if the VG is no longer required, then remove that as well. [root@O-Friday ~]# vgchange -an vg01 0 logical volume(s) in volume group "vg01" now active [root@O-Friday ~]# vgdisplay --- Volume group --- VG Name vg01 System ID Format lvm2 Metadata Areas 2 Metadata Sequence No 11 VG Access read/write VG Status resizable MAX LV 0 Cur LV 0 Open LV 0 Max PV 0 Cur PV 2 Act PV 2 VG Size 19.99 GiB PE Size 4.00 MiB Total PE 5118 Alloc PE / Size 0 / 0 Free PE / Size 5118 / 19.99 GiB VG UUID oAbeGg-j8U2-kCuO-tcmW-HQWv-MqbT-kQdipr --- Volume group --- VG Name openeuler System ID Format lvm2 Metadata Areas 1 Metadata Sequence No 3 VG Access read/write VG Status resizable MAX LV 0 Cur LV 2 Open LV 2 Max PV 0 Cur PV 1 Act PV 1 VG Size <98.00 GiB PE Size 4.00 MiB Total PE 25087 Alloc PE / Size 25087 / <98.00 GiB Free PE / Size 0 / 0 VG UUID I7kRIn-4XeX-0agf-OxRq-ehSi-hqJf-nvkmtU [root@O-Friday ~]# vgremove vg01 Volume group "vg01" successfully removed [root@O-Friday ~]# vgdisplay --- Volume group --- VG Name openeuler System ID Format lvm2 Metadata Areas 1 Metadata Sequence No 3 VG Access read/write VG Status resizable MAX LV 0 Cur LV 2 Open LV 2 Max PV 0 Cur PV 1 Act PV 1 VG Size <98.00 GiB PE Size 4.00 MiB Total PE 25087 Alloc PE / Size 25087 / <98.00 GiB Free PE / Size 0 / 0 VG UUID I7kRIn-4XeX-0agf-OxRq-ehSi-hqJf-nvkmtU 13. 删除pv Delete physical volumes used for volume group **“vg01”**: [root@O-Friday ~]# pvremove /dev/sdb /dev/sdc Labels on physical volume "/dev/sdb" successfully wiped. Labels on physical volume "/dev/sdc" successfully wiped. [root@O-Friday ~]# pvdisplay --- Physical volume --- PV Name /dev/sda2 VG Name openeuler PV Size <98.00 GiB / not usable 3.00 MiB Allocatable yes (but full) PE Size 4.00 MiB Total PE 25087 Free PE 0 Allocated PE 25087 PV UUID Yv3d0c-OjcH-8s93-MsfZ-1JUu-XwU3-NYyPYD 14. 缩减逻辑卷大小 如果已经挂载, 先umount [root@O-Friday mapper]# resize2fs /dev/mapper/vg01-lv001 20G resize2fs 1.46.4 (18-Aug-2021) Please run 'e2fsck -f /dev/mapper/vg01-lv001' first. [root@O-Friday mapper]# e2fsck -f /dev/mapper/vg01-lv001 e2fsck 1.46.4 (18-Aug-2021) 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/vg01-lv001: 11/1966080 files (0.0% non-contiguous), 167453/7861248 blocks [root@O-Friday mapper]# resize2fs /dev/mapper/vg01-lv001 20G resize2fs 1.46.4 (18-Aug-2021) Resizing the filesystem on /dev/mapper/vg01-lv001 to 5242880 (4k) blocks. The filesystem on /dev/mapper/vg01-lv001 is now 5242880 (4k) blocks long. [root@O-Friday mapper]# lvreduce -L 20G /dev/mapper/vg01-lv001 WARNING: Reducing active logical volume to 20.00 GiB. THIS MAY DESTROY YOUR DATA (filesystem etc.) Do you really want to reduce vg01/lv001? [y/n]: y Size of logical volume vg01/lv001 changed from <29.99 GiB (7677 extents) to 20.00 GiB (5120 extents). Logical volume vg01/lv001 successfully resized. [root@O-Friday mapper]# lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS sda 8:0 0 100G 0 disk ├─sda1 8:1 0 2G 0 part /boot └─sda2 8:2 0 98G 0 part ├─openeuler-root 253:0 0 92G 0 lvm / └─openeuler-swap 253:1 0 6G 0 lvm [SWAP] sdb 8:16 0 10G 0 disk └─vg01-lv001 253:2 0 20G 0 lvm sdc 8:32 0 10G 0 disk └─vg01-lv001 253:2 0 20G 0 lvm sdd 8:48 0 10G 0 disk └─vg01-lv001 253:2 0 20G 0 lvm sr0 11:0 1 3.5G 0 rom [root@O-Friday mapper]# e2fsck -f /dev/mapper/vg01-lv001 e2fsck 1.46.4 (18-Aug-2021) 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/vg01-lv001: 11/1310720 files (0.0% non-contiguous), 126322/5242880 blocks 15. 扩展逻辑卷大小 与14是相反操作 三种扩展方式 lvextend -l +40%FREE /dev/mapper/vg01-lv002 lvextend -l +2560 /dev/mapper/vg01-lv002 lvextend -L +10G /dev/mapper/vg01-lv002 [root@O-Friday ~]# lvextend -l +100%FREE /dev/mapper/vg01-lv001 Size of logical volume vg01/lv001 changed from 20.00 GiB (5120 extents) to <29.99 GiB (7677 extents). Logical volume vg01/lv001 successfully resized. 此时,只是扩展了逻辑卷,分区大小并没有变化 扩展分区: 如果是ext4类型 resize2fs /dev/mapper/vg01-lv001 如果是xfs类型 xfs_growfs /dev/mapper/vg01-lv001 [root@O-Friday ~]# resize2fs /dev/mapper/vg01-lv001 resize2fs 1.46.4 (18-Aug-2021) Please run 'e2fsck -f /dev/mapper/vg01-lv001' first. [root@O-Friday ~]# e2fsck -f /dev/mapper/vg01-lv001 e2fsck 1.46.4 (18-Aug-2021) 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/vg01-lv001: 11/1310720 files (0.0% non-contiguous), 126322/5242880 blocks [root@O-Friday ~]# resize2fs /dev/mapper/vg01-lv001 resize2fs 1.46.4 (18-Aug-2021) Resizing the filesystem on /dev/mapper/vg01-lv001 to 7861248 (4k) blocks. The filesystem on /dev/mapper/vg01-lv001 is now 7861248 (4k) blocks long. 重新挂载分区,查看,已经是30G [root@O-Friday ~]# mount /dev/vg01/lv001 /data [root@O-Friday ~]# df -h Filesystem Size Used Avail Use% Mounted on devtmpfs 4.0M 0 4.0M 0% /dev tmpfs 1.7G 12K 1.7G 1% /dev/shm tmpfs 676M 9.2M 667M 2% /run tmpfs 4.0M 0 4.0M 0% /sys/fs/cgroup /dev/mapper/openeuler-root 90G 2.5G 83G 3% / tmpfs 1.7G 0 1.7G 0% /tmp /dev/sda1 2.0G 251M 1.6G 14% /boot /dev/mapper/vg01-lv001 30G 24K 28G 1% /data 16. lvm中添加新磁盘 --查询新增磁盘的名称 fdisk -l Disk /dev/sde: 10 GiB, 10737418240 bytes, 20971520 sectors Disk model: VMware Virtual S Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes --将/dev/sde加入到vg中 [root@O-Friday ~]# vgextend vg01 /dev/sde Physical volume "/dev/sde" successfully created. Volume group "vg01" successfully extended --pv中已经添加了 /dev/sde [root@O-Friday ~]# pvdisplay --- Physical volume --- PV Name /dev/sdb VG Name vg01 PV Size 10.00 GiB / not usable 4.00 MiB Allocatable yes (but full) PE Size 4.00 MiB Total PE 2559 Free PE 0 Allocated PE 2559 PV UUID G3VQkg-izg2-8hNm-9bw4-Ex5r-a0ec-YBEpPr --- Physical volume --- PV Name /dev/sdc VG Name vg01 PV Size 10.00 GiB / not usable 4.00 MiB Allocatable yes (but full) PE Size 4.00 MiB Total PE 2559 Free PE 0 Allocated PE 2559 PV UUID 16j3C2-lPOn-KdR4-R1By-NoJS-UZ8S-xj9jyy --- Physical volume --- PV Name /dev/sdd VG Name vg01 PV Size 10.00 GiB / not usable 4.00 MiB Allocatable yes (but full) PE Size 4.00 MiB Total PE 2559 Free PE 0 Allocated PE 2559 PV UUID YHoxPb-fDi5-P8By-dzXh-7LPz-a4BO-j6um2R --- Physical volume --- PV Name /dev/sde VG Name vg01 PV Size 10.00 GiB / not usable 4.00 MiB Allocatable yes PE Size 4.00 MiB Total PE 2559 Free PE 2559 Allocated PE 0 PV UUID PaMgdp-4VS7-u7Nv-m7Zg-FUPK-uTBA-yDHmkE --- Physical volume --- PV Name /dev/sda2 VG Name openeuler PV Size <98.00 GiB / not usable 3.00 MiB Allocatable yes (but full) PE Size 4.00 MiB Total PE 25087 Free PE 0 Allocated PE 25087 PV UUID Yv3d0c-OjcH-8s93-MsfZ-1J --添加后查看vg, 已有10G free空间 [root@O-Friday ~]# vgdisplay vg01 --- Volume group --- VG Name vg01 System ID Format lvm2 Metadata Areas 4 Metadata Sequence No 5 VG Access read/write VG Status resizable MAX LV 0 Cur LV 1 Open LV 0 Max PV 0 Cur PV 4 Act PV 4 VG Size 39.98 GiB PE Size 4.00 MiB Total PE 10236 Alloc PE / Size 7677 / <29.99 GiB Free PE / Size 2559 / <10.00 GiB VG UUID PEANLD-I1ET-hpk1-jN9V-CxZ6-ktRB-veif7v --扩展lv,扩展所有FREE [root@O-Friday ~]# lvextend -l +100%FREE /dev/mapper/vg01-lv001 Size of logical volume vg01/lv001 changed from <29.99 GiB (7677 extents) to 39.98 GiB (10236 extents). Logical volume vg01/lv001 successfully resized. --扩展分区, 需要先执行e2fsck [root@O-Friday ~]# resize2fs /dev/mapper/vg01-lv001 resize2fs 1.46.4 (18-Aug-2021) Please run 'e2fsck -f /dev/mapper/vg01-lv001' first. [root@O-Friday ~]# e2fsck -f /dev/mapper/vg01-lv001 e2fsck 1.46.4 (18-Aug-2021) 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/vg01-lv001: 11/1966080 files (0.0% non-contiguous), 167442/7861248 blocks [root@O-Friday ~]# resize2fs /dev/mapper/vg01-lv001 resize2fs 1.46.4 (18-Aug-2021) Resizing the filesystem on /dev/mapper/vg01-lv001 to 10481664 (4k) blocks. The filesystem on /dev/mapper/vg01-lv001 is now 10481664 (4k) blocks long. --重新挂载分区,查看 [root@O-Friday ~]# mount /dev/vg01/lv001 /data [root@O-Friday ~]# df -h Filesystem Size Used Avail Use% Mounted on devtmpfs 4.0M 0 4.0M 0% /dev tmpfs 1.7G 12K 1.7G 1% /dev/shm tmpfs 676M 9.2M 667M 2% /run tmpfs 4.0M 0 4.0M 0% /sys/fs/cgroup /dev/mapper/openeuler-root 90G 2.5G 83G 3% / tmpfs 1.7G 0 1.7G 0% /tmp /dev/sda1 2.0G 251M 1.6G 14% /boot /dev/mapper/vg01-lv001 40G 24K 38G 1% /data 17. /etc/fstab 在Linux系统中，`/etc/fstab`文件用于定义系统挂载文件系统的方式，包括本地磁盘、网络共享、CD-ROM等等。 每一行代表一个文件系统，每个字段用制表符分隔。以下是每个字段的含义： 1. **文件系统**: 这个字段表示要挂载的文件系统的设备名或者UUID。例如：`/dev/sda1`或`UUID=4b5324c4-2b8a-4f06-9b6c-bb5f5d5d5b9a`。也可以用LABEL来指定设备名称，例如：`LABEL=MyDisk`。注意：如果使用UUID或LABEL方式指定设备名称，则不受分区名的影响。 2. **挂载点**: 这个字段指定文件系统的挂载点，即文件系统要挂载到哪个目录下。例如：`/` 或 `/home`。 3. **文件系统类型**: 这个字段指定文件系统的类型。例如：ext4、ntfs、vfat等。如果不知道文件系统类型，可以在终端中使用 `blkid` 命令查看。 4. **选项**: 这个字段指定了文件系统的挂载选项，例如是否允许读写、是否允许执行程序、是否允许设备文件、是否自动挂载等等。多个选项之间用逗号分隔。 - `defaults`：默认选项，包括读取和写入权限、执行权限以及自动挂载。 - `ro`：只读选项，只允许读取文件系统中的内容，禁止修改。 - `noauto`：禁止自动挂载选项，文件系统不会在系统启动时自动挂载。 - `user`：允许普通用户挂载选项，通常只有超级用户才有挂载权限。 - `noexec`：禁止执行选项，防止在文件系统中执行程序和脚本文件。 - `nosuid`：禁止设置用户ID和组ID选项，防止在文件系统中执行 SUID 和 SGID 程序。 - `nodev`：禁止创建设备文件选项，防止在文件系统中创建设备文件。 - `noatime`：禁止更新访问时间选项，不更新最后一次访问时间，以提高性能。 - `nodiratime`：禁止更新目录访问时间选项，不更新目录最后一次访问时间，以提高性能。 - `relatime`：相对更新访问时间选项，只在访问时间落后于修改时间或创建时间时更新访问时间。 - `async`：异步选项，允许异步读取和写入，以提高性能。但是这样可能会导致数据丢失，因为写入操作不会立即写入磁盘。 5. **备份频率**: 这个字段指定了备份频率。在 Linux 中，`0` 表示不备份，`1` 表示每天备份一次，`2` 表示每周备份一次，`3` 表示每月备份一次。如果不需要备份，则可以将此字段设置为 0。 6. **检查顺序**: 这个字段用于指定系统引导时，需要检查哪些文件系统。默认情况下，根文件系统（/）的检查顺序为 1，其他文件系统为 2。可以将此字段设置为 0，表示不进行检查。 [root@O-Friday ~]# cat /etc/fstab # # /etc/fstab # Created by anaconda on Sun Mar 5 02:52:57 2023 # # Accessible filesystems, by reference, are maintained under '/dev/disk/'. # See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info. # # After editing this file, run 'systemctl daemon-reload' to update systemd # units generated from this file. # /dev/mapper/openeuler-root / ext4 defaults 1 1 UUID=3ee8700a-3e9c-4c83-9336-87fa08836b84 /boot ext4 defaults 1 2 /dev/mapper/openeuler-swap none swap defaults 0 0