Linux LVM磁盘分区管理

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-PSMQez
2. 创建VG
vgname = 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 19.99g
4. 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 vg01
8. 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
 
作者:dong_rayne原文地址:https://www.cnblogs.com/dong-rayne/p/17219397.html

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