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【Linux分享】RAID与逻辑卷管理_linux 软raid
作者：数据科学创新者 | 2024-01-31 17:52:59
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linux 软raid
RAID和逻辑卷
写在开头：
磁盘有价，数据无价！
请读者在执行任何与磁盘相关操作之前，务必三思而后行。
不论有无十足把握，请准备好回退方案。
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一、RAID管理
（1）RAID介绍
RAID(Redundant Array of Independent Disks)，独立冗余磁盘阵列。在早期大部分采用的都是单块磁盘进行数据存储和读写，I/O性能非常低，且存储容量较低。而且单块磁盘容易出现故障。为了解决问题，提出了将多块硬盘结合在一起使用，来提高I/O性能和容量，并提高一定的冗余性。于是RAID技术就出现了。下面介绍几种常用的RAID。
RAID0
- 工作原理：将N块硬盘组合在一起使用，即可用于将近N倍的读写性能。容量也是所有硬盘容量的总和。
- 优点：读写性能和存储容量都得到提升
- 缺点：数据安全性较低，整个RAID0组中任何一块硬盘损坏都会导致数据丢失。没有冗余能力。
- 磁盘数量：最少需要两块磁盘
RAID1
- 工作原理：将写入磁盘的数据镜像到另一块磁盘上，当一块磁盘损坏的时候，另一块磁盘可以直接使用。
- 优点：安全性高，技术简单
- 缺点：实现成本高，磁盘利用率低
- 磁盘数量：必须是偶数
RAID3
- 工作原理：在raid组里面专门用一个磁盘来保存XOR（异或校验算法）校验值，这块盘我们称为校验盘。当我们raid组中硬盘出现故障的时候，可以通过XOR算法来重建数据。
- 优点：能够提高读写性能，提供冗余功能，相比raid1成本更低。
- 缺点：当写操作频繁的时，校验盘因为频繁擦写，坏盘几率更大
- 磁盘数量：最少需要三块磁盘。
RAID5
- 工作原理：与RAID3工作原理相似，不同点在于，RAID５的校验值是存放在不同的硬盘上，灭有专门的校验盘。
- 优点：兼顾了存储性能、数据安全和成本等各方面因素，是综合性能最佳的解决方案。
- 缺点：写入速度比对单个磁盘稍慢
- 磁盘数量：最少需要三块磁盘
RAID6
- 工作原理：与RAID5类似，在次基础上RAID6增加了一个校验值，可以同时允许两块磁盘损坏，通过校验算法来重建数据。
- 优点：快速的读取性能，更高的容错能力
- 缺点：写入速度稍慢，成本更高，一般用于RAID10的替代方案。
- 磁盘数量：最少需要4块硬盘
RAID10
- 工作原理：兼具了RAID1和RAID0的优点，将两个raid1组成raid0。
- 优点：具备RAID0的读写性能以及RAID1的容错能力，完美的解决方案。
- 缺点：成本极高。
- 磁盘数量：最少4块磁盘，且必须是4的倍数。
拓展
在RAID成员失效、但没超过冗余能力时，RAID会进入降级（Degraded）状态
降级状态下的性能和可靠性都会大幅降低
为降级RAID组加入新的成员盘会进入重建（Rebuild）状态
重建过程会产生大量磁盘IO，会对存储系统性能造成负面影响
重建操作可能会与业务争夺资源，进一步增加重建耗时
重建状态下的可靠性与降级相同
热备（HotSpare）是阵列组中的在线自动替补机制，可设置热备盘在阵列组降级时自动补位，进入重建状态；有全局热备和局部热备两种
全局热备：存储系统中任意阵列组降级时皆会自动补位
专用热备：指定的某些阵列组降级时才会自动补位
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硬RAID和软RAID
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硬RAID：通过独立的RAID卡或者控制器来实现RIAD功能。
- 优点：独立于操作系统之外，不会从磁盘上占据读写性能，磁盘更换更加方便。
- 缺点：成本较高，当控制器故障，必须找一个兼容控制器更换。配置难以更改
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软RAID：没有独立的RAID卡，由操作系统和CPU来实现RAID功能。
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优点：成本较低，操作简单。
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缺点：会降低RAID性能，并且不允许在操作系统之间共享。性能和可靠性都依赖于CPU。
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（2）RAID配置
使用mdadm命令来管理RAID组。
RAID0配置
[root@rhce ~]# mdadm -C /dev/md0 -l 0 -n 2 /dev/sda /dev/sdb mdadm: Defaulting to version 1.2 metadata mdadm: array /dev/md0 started. mdadm 创建raid -C 创建模式 /dev/md0 raid组的文件名 -l raid基本 0 raid0 -n 使用磁盘数量 /dev/sda 使用磁盘名称 [root@rhce ~]# mdadm -D /dev/md0 /dev/md0: Version : 1.2 Creation Time : Fri Aug 25 14:57:12 2023 Raid Level : raid0 Array Size : 41908224 (39.97 GiB 42.91 GB) Raid Devices : 2 Total Devices : 2 Persistence : Superblock is persistent Update Time : Fri Aug 25 14:57:12 2023 State : clean Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 Layout : -unknown- Chunk Size : 512K Consistency Policy : none Name : rhce:0 (local to host rhce) UUID : c1134565:c3145720:0077e0cb:a0166319 Events : 0 Number Major Minor RaidDevice State 0 8 0 0 active sync /dev/sda 1 8 16 1 active sync /dev/sdb [root@rhce ~]# mkfs.ext4 /dev/md0 mke2fs 1.46.5 (30-Dec-2021) Creating filesystem with 10477056 4k blocks and 2621440 inodes Filesystem UUID: f477109d-43fd-4be1-8b80-3ce75c00adf3 Superblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 4096000, 7962624 Allocating group tables: done Writing inode tables: done Creating journal (65536 blocks): done Writing superblocks and filesystem accounting information: done [root@rhce ~]# lsblk /dev/md0 NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS md0 9:0 0 40G 0 raid0
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RAID1配置
[root@rhce ~]# mdadm -C /dev/md1 -l 1 -n 2 /dev/sda /dev/sdb -x 1 /dev/sdc mdadm: Note: this array has metadata at the start and may not be suitable as a boot device. If you plan to store '/boot' on this device please ensure that your boot-loader understands md/v1.x metadata, or use --metadata=0.90 Continue creating array? (y/n) y mdadm: Defaulting to version 1.2 metadata mdadm: array /dev/md1 started. [root@rhce ~]# mdadm -D /dev/md1 /dev/md1: Version : 1.2 Creation Time : Fri Aug 25 15:04:50 2023 Raid Level : raid1 Array Size : 20954112 (19.98 GiB 21.46 GB) Used Dev Size : 20954112 (19.98 GiB 21.46 GB) Raid Devices : 2 Total Devices : 3 Persistence : Superblock is persistent Update Time : Fri Aug 25 15:06:35 2023 State : clean Active Devices : 2 Working Devices : 3 Failed Devices : 0 Spare Devices : 1 Consistency Policy : resync Name : rhce:1 (local to host rhce) UUID : 10b89b07:a12c11c8:c8db35dd:79d24c1d Events : 17 Number Major Minor RaidDevice State 0 8 0 0 active sync /dev/sda 1 8 16 1 active sync /dev/sdb 2 8 32 - spare /dev/sdc [root@rhce ~]# mkfs.ext4 /dev/md1 mke2fs 1.46.5 (30-Dec-2021) Creating filesystem with 5238528 4k blocks and 1310720 inodes Filesystem UUID: 8550c865-1078-4b6d-8cf2-4d2d3204f19a Superblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 4096000 Allocating group tables: done Writing inode tables: done Creating journal (32768 blocks): done Writing superblocks and filesystem accounting information: done [root@rhce ~]# lsblk /dev/md1 NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS md1 9:1 0 20G 0 raid1
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RAID5配置
[root@rhce ~]# mdadm -C /dev/md5 -l 5 -n 3 /dev/sd{a..c} -x 1 /dev/sdd mdadm: Defaulting to version 1.2 metadata mdadm: array /dev/md5 started. [root@rhce ~]# mdadm -D /dev/md5 /dev/md5: Version : 1.2 Creation Time : Fri Aug 25 15:17:33 2023 Raid Level : raid5 Array Size : 41908224 (39.97 GiB 42.91 GB) Used Dev Size : 20954112 (19.98 GiB 21.46 GB) Raid Devices : 3 Total Devices : 4 Persistence : Superblock is persistent Update Time : Fri Aug 25 15:19:18 2023 State : clean Active Devices : 3 Working Devices : 4 Failed Devices : 0 Spare Devices : 1 Layout : left-symmetric Chunk Size : 512K Consistency Policy : resync Name : rhce:5 (local to host rhce) UUID : c8da269e:85a80803:721a7849:70388d16 Events : 18 Number Major Minor RaidDevice State 0 8 0 0 active sync /dev/sda 1 8 16 1 active sync /dev/sdb 4 8 32 2 active sync /dev/sdc 3 8 48 - spare /dev/sdd [root@rhce ~]# mkfs.ext4 /dev/md5 mke2fs 1.46.5 (30-Dec-2021) Creating filesystem with 10477056 4k blocks and 2621440 inodes Filesystem UUID: 00088c6c-60dc-4eb6-a99e-701477ce1eae Superblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 4096000, 7962624 Allocating group tables: done Writing inode tables: done Creating journal (65536 blocks): done Writing superblocks and filesystem accounting information: done [root@rhce ~]# lsblk /dev/md5 NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS md5 9:5 0 40G 0 raid5
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RAID6配置
[root@rhce ~]# mdadm -C /dev/md6 -l 6 -n 4 /dev/sd{a..d} -x 1 /dev/sde mdadm: Defaulting to version 1.2 metadata mdadm: array /dev/md6 started. [root@rhce ~]# mdadm /dev/md6 /dev/md6: 39.97GiB raid6 4 devices, 1 spare. Use mdadm --detail for more detail. [root@rhce ~]# mdadm -D /dev/md6 /dev/md6: Version : 1.2 Creation Time : Fri Aug 25 15:24:55 2023 Raid Level : raid6 Array Size : 41908224 (39.97 GiB 42.91 GB) Used Dev Size : 20954112 (19.98 GiB 21.46 GB) Raid Devices : 4 Total Devices : 5 Persistence : Superblock is persistent Update Time : Fri Aug 25 15:25:02 2023 State : clean, resyncing Active Devices : 4 Working Devices : 5 Failed Devices : 0 Spare Devices : 1 Layout : left-symmetric Chunk Size : 512K Consistency Policy : resync Resync Status : 10% complete Name : rhce:6 (local to host rhce) UUID : 931508e9:3bd8d9e6:444ae93b:fff78515 Events : 1 Number Major Minor RaidDevice State 0 8 0 0 active sync /dev/sda 1 8 16 1 active sync /dev/sdb 2 8 32 2 active sync /dev/sdc 3 8 48 3 active sync /dev/sdd 4 8 64 - spare /dev/sde [root@rhce ~]# mkfs.ext4 /dev/md6 mke2fs 1.46.5 (30-Dec-2021) Creating filesystem with 10477056 4k blocks and 2621440 inodes Filesystem UUID: 5e740994-118f-4384-97a9-94ced2117cb3 Superblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 4096000, 7962624 Allocating group tables: done Writing inode tables: done Creating journal (65536 blocks): done Writing superblocks and filesystem accounting information: done [root@rhce ~]# lsblk /dev/md6 NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS md6 9:6 0 40G 0 raid6
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RAID10配置
[root@rhce ~]# mdadm -C /dev/md0 -l 10 -n 4 /dev/sd{a..d} mdadm: Defaulting to version 1.2 metadata mdadm: array /dev/md0 started. [root@rhce ~]# mdadm -D /dev/md0 /dev/md0: Version : 1.2 Creation Time : Fri Aug 25 15:39:48 2023 Raid Level : raid10 Array Size : 41908224 (39.97 GiB 42.91 GB) Used Dev Size : 20954112 (19.98 GiB 21.46 GB) Raid Devices : 4 Total Devices : 4 Persistence : Superblock is persistent Update Time : Fri Aug 25 15:39:48 2023 State : clean, resyncing Active Devices : 4 Working Devices : 4 Failed Devices : 0 Spare Devices : 0 Layout : near=2 Chunk Size : 512K Consistency Policy : resync Resync Status : 3% complete Name : rhce:0 (local to host rhce) UUID : 3b4213f8:21c6b204:bd24ec4a:250d2378 Events : 0 Number Major Minor RaidDevice State 0 8 0 0 active sync set-A /dev/sda 1 8 16 1 active sync set-B /dev/sdb 2 8 32 2 active sync set-A /dev/sdc 3 8 48 3 active sync set-B /dev/sdd [root@rhce ~]# mdadm -C /dev/md10 -n /dev/ Display all 178 possibilities? (y or n) [root@rhce ~]# mkfs.ext4 /dev/md0 mke2fs 1.46.5 (30-Dec-2021) Creating filesystem with 10477056 4k blocks and 2621440 inodes Filesystem UUID: 6e7895e3-9557-4097-925e-8985ecf95ccc Superblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 4096000, 7962624 Allocating group tables: done Writing inode tables: done Creating journal (65536 blocks): done Writing superblocks and filesystem accounting information: done [root@rhce ~]# lsblk /dev/md0 NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS md0 9:0 0 40G 0 raid10 [root@rhce ~]# mkfs.ext4 /dev/md0 mke2fs 1.46.5 (30-Dec-2021) Creating filesystem with 10477056 4k blocks and 2621440 inodes Filesystem UUID: 6e7895e3-9557-4097-925e-8985ecf95ccc Superblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 4096000, 7962624 Allocating group tables: done Writing inode tables: done Creating journal (65536 blocks): done Writing superblocks and filesystem accounting information: done [root@rhce ~]# lsblk /dev/md0 NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS md0 9:0 0 40G 0 raid10
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删除RAID
停止RAID阵列 [root@rhce ~]# mdadm -S /dev/md0 mdadm: stopped /dev/md0 清除RAID成员中的超级快信息 [root@rhce ~]# mdadm --zero-superblock /dev/sd{a..d} 如果没有清除超级块信息，当我们重新创建RAID的时候，会提醒我们该磁盘以及在某个RAID阵列 [root@rhce ~]# mdadm -C /dev/md0 -l 10 -n 4 /dev/sd{a..d} mdadm: /dev/sda appears to be part of a raid array: level=raid10 devices=4 ctime=Fri Aug 25 15:54:10 2023 mdadm: /dev/sdb appears to be part of a raid array: level=raid10 devices=4 ctime=Fri Aug 25 15:54:10 2023 mdadm: /dev/sdc appears to be part of a raid array: level=raid10 devices=4 ctime=Fri Aug 25 15:54:10 2023 mdadm: /dev/sdd appears to be part of a raid array: level=raid10 devices=4 ctime=Fri Aug 25 15:54:10 2023
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（3）RAID阵列磁盘损害模拟
以RAID5为例，当损坏一块磁盘的时候，热备盘自动更换，数据重构。
[root@rhce ~]# mkdir /md5 [root@rhce ~]# mount /dev/md5 /md5/ [root@rhce ~]# df -H /dev/md5 Filesystem Size Used Avail Use% Mounted on /dev/md5 42G 25k 40G 1% /md5 [root@rhce ~]# mdadm -D /dev/md5 /dev/md5: Version : 1.2 Creation Time : Fri Aug 25 15:58:37 2023 Raid Level : raid5 Array Size : 41908224 (39.97 GiB 42.91 GB) Used Dev Size : 20954112 (19.98 GiB 21.46 GB) Raid Devices : 3 Total Devices : 4 Persistence : Superblock is persistent Update Time : Fri Aug 25 16:00:23 2023 State : active Active Devices : 3 Working Devices : 4 Failed Devices : 0 Spare Devices : 1 Layout : left-symmetric Chunk Size : 512K Consistency Policy : resync Name : rhce:5 (local to host rhce) UUID : f0d45dfb:cb5696d9:1d0077e2:d785cba2 Events : 23 Number Major Minor RaidDevice State 0 8 0 0 active sync /dev/sda 1 8 16 1 active sync /dev/sdb 4 8 32 2 active sync /dev/sdc 3 8 48 - spare /dev/sdd 往RAID5中写入数据 [root@rhce ~]# mount /dev/sr0 /cdrow/ mount: /cdrow: WARNING: source write-protected, mounted read-only. [root@rhce ~]# cp -rf /cdrow/ /md5/ //将光盘镜像中数据全部复制到raid5中 [root@rhce ~]# ls /md5/ cdrow lost+found [root@rhce ~]# du -h /md5/ 16K /md5/lost+found 108M /md5/cdrow/images/pxeboot 857M /md5/cdrow/images 1.2G /md5/cdrow/BaseOS/Packages 2.4M /md5/cdrow/BaseOS/repodata 1.2G /md5/cdrow/BaseOS 7.0G /md5/cdrow/AppStream/Packages 7.7M /md5/cdrow/AppStream/repodata 7.0G /md5/cdrow/AppStream 109M /md5/cdrow/isolinux 2.3M /md5/cdrow/EFI/BOOT/fonts 6.5M /md5/cdrow/EFI/BOOT 6.5M /md5/cdrow/EFI 9.1G /md5/cdrow 9.1G /md5/ 模拟/dev/sdb磁盘损坏 mdadm: set /dev/sdb faulty in /dev/md5 [root@rhce ~]# mdadm -D /dev/md5 /dev/md5: Version : 1.2 Creation Time : Fri Aug 25 15:58:37 2023 Raid Level : raid5 Array Size : 41908224 (39.97 GiB 42.91 GB) Used Dev Size : 20954112 (19.98 GiB 21.46 GB) Raid Devices : 3 Total Devices : 4 Persistence : Superblock is persistent Update Time : Fri Aug 25 16:04:57 2023 State : clean, degraded, recovering Active Devices : 2 Working Devices : 3 Failed Devices : 1 Spare Devices : 1 Layout : left-symmetric Chunk Size : 512K Consistency Policy : resync Rebuild Status : 10% complete Name : rhce:5 (local to host rhce) UUID : f0d45dfb:cb5696d9:1d0077e2:d785cba2 Events : 27 Number Major Minor RaidDevice State 0 8 0 0 active sync /dev/sda 3 8 48 1 spare rebuilding /dev/sdd 4 8 32 2 active sync /dev/sdc 1 8 16 - faulty /dev/sdb [root@rhce ~]# du -h /md5/ 16K /md5/lost+found 108M /md5/cdrow/images/pxeboot 857M /md5/cdrow/images 1.2G /md5/cdrow/BaseOS/Packages 2.4M /md5/cdrow/BaseOS/repodata 1.2G /md5/cdrow/BaseOS 7.0G /md5/cdrow/AppStream/Packages 7.7M /md5/cdrow/AppStream/repodata 7.0G /md5/cdrow/AppStream 109M /md5/cdrow/isolinux 2.3M /md5/cdrow/EFI/BOOT/fonts 6.5M /md5/cdrow/EFI/BOOT 6.5M /md5/cdrow/EFI 9.1G /md5/cdrow 9.1G /md5/
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二、逻辑卷管理
（1）逻辑卷介绍
LVM(Logical Volume Manager)逻辑卷管理实在Linux环境下对磁盘分区进行管理的一种机制。在大部分系统中都有类型LVM这种磁盘管理方式。LVM可以通过简单的操作来完成磁盘的扩容和缩容，相比于之前的分区，虽然也可以进行扩容，但是有可能会出现数据丢失的情况。
LVM定义
- 物理设备：用于保存数据的存储设备。条目是块设备，可以是磁盘分区，也可以是整个磁盘、RAID阵列或者SAN磁盘。
- 物理卷(PV)：要创建逻辑卷必须将物理设备初始化为物理卷。LVM系统会将物理卷分成物理区块(PE)。
- 卷组(VG)：卷组是存储池。由一个或多个物理卷组成。一个PV只能分配给一个VG。VG可以包含未使用的空间和任意数目的逻辑卷。
- 逻辑卷(LV)：逻辑卷是提供给应用、用户和系统所使用的“存储设备”。
（2）逻辑卷配置
以下实例完整的磁盘为例。也可以将磁盘进行分区后，来创建逻辑卷。
创建逻辑卷
创建逻辑卷基本步骤：
- 初始化物理设备为物理卷
- 创建卷组
- 创建逻辑卷
- 添加文件系统
创建物理卷
使用pvcreate命令将物理设备标记为物理卷
[root@rhce ~]# pvcreate /dev/sda /dev/sdb
Physical volume "/dev/sda" successfully created.
Physical volume "/dev/sdb" successfully created.
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使用pvdisplay或者pvs利用查看物理卷信息。
[root@rhce ~]# pvdisplay --- Physical volume --- PV Name /dev/nvme0n1p2 VG Name rhel PV Size <19.00 GiB / not usable 3.00 MiB Allocatable yes (but full) PE Size 4.00 MiB Total PE 4863 Free PE 0 Allocated PE 4863 PV UUID HPRENt-Y8n0-cr0N-1u8h-3oGG-RXgY-9oBMZf "/dev/sda" is a new physical volume of "20.00 GiB" --- NEW Physical volume --- PV Name /dev/sda VG Name PV Size 20.00 GiB Allocatable NO PE Size 0 Total PE 0 Free PE 0 Allocated PE 0 PV UUID zJ0SHT-rdQO-NzL4-ySD3-G95F-LKKu-B0lEAg "/dev/sdb" is a new physical volume of "20.00 GiB" --- NEW Physical volume --- PV Name /dev/sdb VG Name PV Size 20.00 GiB Allocatable NO PE Size 0 Total PE 0 Free PE 0 Allocated PE 0 PV UUID BrBVT9-semZ-0i6u-wzgH-jdVd-chGj-k4XBZI [root@rhce ~]# pvs PV VG Fmt Attr PSize PFree /dev/nvme0n1p2 rhel lvm2 a-- <19.00g 0 /dev/sda lvm2 --- 20.00g 20.00g /dev/sdb lvm2 --- 20.00g 20.00g
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创建卷组
使用vgcreate命令将一个或多个物理卷组成一个卷组。
[root@rhce ~]# vgcreate vg0 /dev/sda /dev/sdb
Volume group "vg0" successfully created
创建一个名称为vg0的卷组。大小是/dev/sda和/dev/sdb两个PV的大小之和(以PE为单位计算)。
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使用vgdisplay或者vgs查看卷组信息。
[root@rhce ~]# vgdisplay --- Volume group --- VG Name rhel 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 <19.00 GiB PE Size 4.00 MiB Total PE 4863 Alloc PE / Size 4863 / <19.00 GiB Free PE / Size 0 / 0 VG UUID V6MZGK-aQ0s-oWqG-qppZ-oP7N-b7vo-mJlWZC --- Volume group --- VG Name vg0 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 39.99 GiB PE Size 4.00 MiB Total PE 10238 Alloc PE / Size 0 / 0 Free PE / Size 10238 / 39.99 GiB VG UUID Ge2w5w-Wx5w-4ALl-qe1Z-oqyr-wGvS-TRYIPz [root@rhce ~]# vgs VG #PV #LV #SN Attr VSize VFree rhel 1 2 0 wz--n- <19.00g 0 vg0 2 0 0 wz--n- 39.99g 39.99g
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创建逻辑卷
使用lvcreate命令创建逻辑卷。
[root@rhce ~]# lvcreate -n lv01 -L 10G vg0
Logical volume "lv01" created.
从vg0卷组中创建一个名称为lv01大小为10G的逻辑卷
[root@rhce ~]# lvcreate -n lv02 -l 250 vg0
Logical volume "lv02" created.
从vg0卷组中创建一个有250个PE大小的逻辑卷
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使用lvdisplay或者lvs查看逻辑卷信息。
[root@rhce ~]# lvdisplay --- Logical volume --- LV Path /dev/rhel/swap LV Name swap VG Name rhel LV UUID bwugab-kZjm-Eb2M-Z4Fv-eBkH-4ACa-YCxkrX LV Write Access read/write LV Creation host, time localhost.localdomain, 2023-07-24 14:13:15 +0800 LV Status available # open 2 LV Size 2.00 GiB Current LE 512 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 253:1 --- Logical volume --- LV Path /dev/rhel/root LV Name root VG Name rhel LV UUID v0OM7E-yWaP-eSF2-vCQZ-cg6P-Q3jg-G9bzS4 LV Write Access read/write LV Creation host, time localhost.localdomain, 2023-07-24 14:13:15 +0800 LV Status available # open 1 LV Size <17.00 GiB Current LE 4351 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 253:0 --- Logical volume --- LV Path /dev/vg0/lv01 LV Name lv01 VG Name vg0 LV UUID bRX08g-50Y2-Tcnx-HAnU-bBf0-uWnf-eVGLqu LV Write Access read/write LV Creation host, time rhce, 2023-08-25 17:00:23 +0800 LV Status available # open 0 LV Size 10.00 GiB Current LE 2560 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 253:2 --- Logical volume --- LV Path /dev/vg0/lv02 LV Name lv02 VG Name vg0 LV UUID hAqSV4-KbwI-xu6a-IwwB-4nZS-jjDb-CsdkEt LV Write Access read/write LV Creation host, time rhce, 2023-08-25 17:01:02 +0800 LV Status available # open 0 LV Size 1000.00 MiB Current LE 250 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 253:3 [root@rhce ~]# lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert root rhel -wi-ao---- <17.00g swap rhel -wi-ao---- 2.00g lv01 vg0 -wi-a----- 10.00g lv02 vg0 -wi-a----- 1000.00m
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添加文件系统
[root@rhce ~]# mkfs.xfs /dev/vg0/lv01 meta-data=/dev/vg0/lv01 isize=512 agcount=4, agsize=655360 blks = sectsz=512 attr=2, projid32bit=1 = crc=1 finobt=1, sparse=1, rmapbt=0 = reflink=1 bigtime=1 inobtcount=1 data = bsize=4096 blocks=2621440, imaxpct=25 = sunit=0 swidth=0 blks naming =version 2 bsize=4096 ascii-ci=0, ftype=1 log =internal log bsize=4096 blocks=2560, version=2 = sectsz=512 sunit=0 blks, lazy-count=1 realtime =none extsz=4096 blocks=0, rtextents=0 [root@rhce ~]# mkfs.ext4 /dev/vg0/lv02 mke2fs 1.46.5 (30-Dec-2021) Creating filesystem with 256000 4k blocks and 64000 inodes Filesystem UUID: b6263632-28cb-440a-ad99-1da7d43d7bd8 Superblock backups stored on blocks: 32768, 98304, 163840, 229376 Allocating group tables: done Writing inode tables: done Creating journal (4096 blocks): done Writing superblocks and filesystem accounting information: done
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逻辑卷扩容
扩容重要步骤：
- 扩充逻辑卷大小
- 扩充文件系统大小
扩容逻辑卷，如果卷组上还有多余的空闲空间即可之间分配给逻辑卷，如果没有空闲空间，就需要初始化物理卷，再将卷组扩充，提供给逻辑卷扩容的空间。
扩展卷组
使用vgextend命令向卷组中添加新物理卷。
[root@rhce ~]# vgextend vg0 /dev/sdc Physical volume "/dev/sdc" successfully created. Volume group "vg0" successfully extended [root@rhce ~]# vgdisplay vg0 --- Volume group --- VG Name vg0 System ID Format lvm2 Metadata Areas 3 Metadata Sequence No 4 VG Access read/write VG Status resizable MAX LV 0 Cur LV 2 Open LV 0 Max PV 0 Cur PV 3 Act PV 3 VG Size <59.99 GiB PE Size 4.00 MiB Total PE 15357 Alloc PE / Size 2810 / <10.98 GiB Free PE / Size 12547 / 49.01 GiB VG UUID Ge2w5w-Wx5w-4ALl-qe1Z-oqyr-wGvS-TRYIPz
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扩展逻辑卷
使用lvextend命令来扩展逻辑卷大小。
[root@rhce ~]# lvextend -L +5G /dev/vg0/lv01
Size of logical volume vg0/lv01 changed from 10.00 GiB (2560 extents) to 15.00 GiB (3840 extents).
Logical volume vg0/lv01 successfully resized.
[root@rhce ~]# lvs /dev/vg0/lv01
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
lv01 vg0 -wi-a----- 15.00g
[root@rhce ~]# lvextend -l 500 /dev/vg0/lv02
Size of logical volume vg0/lv02 changed from 1000.00 MiB (250 extents) to 1.95 GiB (500 extents).
Logical volume vg0/lv02 successfully resized.
[root@rhce ~]# lvs /dev/vg0/lv02
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
lv02 vg0 -wi-a----- 1.95g
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扩展示例
lvextend -L +5G 向逻辑卷里面添加5G
lvextend -L 5G 将逻辑卷大小调整到正好5G
lvextend -l +500 向逻辑卷里面添加500个PE
lvextend -l 500 将逻辑卷大小调整到500个PE
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扩展文件系统
不同的文件系统有不同的命令
扩容EXT4文件系统
使用resize2fs来扩展文件系统
[root@rhce ~]# resize2fs /dev/vg0/lv02
resize2fs 1.46.5 (30-Dec-2021)
Resizing the filesystem on /dev/vg0/lv02 to 512000 (4k) blocks.
The filesystem on /dev/vg0/lv02 is now 512000 (4k) blocks long.
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扩容XFS文件系统
使用xfs_growfs命令来扩展文件系统，xfs系统必须要挂载之后，才能扩展。
[root@rhce ~]# mkdir /date [root@rhce ~]# mount /dev/vg0/lv01 /date/ [root@rhce ~]# df -h Filesystem Size Used Avail Use% Mounted on devtmpfs 4.0M 0 4.0M 0% /dev tmpfs 1.8G 0 1.8G 0% /dev/shm tmpfs 728M 9.8M 718M 2% /run /dev/mapper/rhel-root 17G 4.7G 13G 28% / /dev/nvme0n1p1 1014M 292M 723M 29% /boot tmpfs 364M 96K 364M 1% /run/user/0 /dev/sr0 9.0G 9.0G 0 100% /run/media/root/RHEL-9-2-0-BaseOS-x86_64 /dev/mapper/vg0-lv01 10G 104M 9.9G 2% /date [root@rhce ~]# xfs_growfs /date/ meta-data=/dev/mapper/vg0-lv01 isize=512 agcount=4, agsize=655360 blks = sectsz=512 attr=2, projid32bit=1 = crc=1 finobt=1, sparse=1, rmapbt=0 = reflink=1 bigtime=1 inobtcount=1 data = bsize=4096 blocks=2621440, imaxpct=25 = sunit=0 swidth=0 blks naming =version 2 bsize=4096 ascii-ci=0, ftype=1 log =internal log bsize=4096 blocks=2560, version=2 = sectsz=512 sunit=0 blks, lazy-count=1 realtime =none extsz=4096 blocks=0, rtextents=0 data blocks changed from 2621440 to 3932160 [root@rhce ~]# df -h Filesystem Size Used Avail Use% Mounted on devtmpfs 4.0M 0 4.0M 0% /dev tmpfs 1.8G 0 1.8G 0% /dev/shm tmpfs 728M 9.8M 718M 2% /run /dev/mapper/rhel-root 17G 4.7G 13G 28% / /dev/nvme0n1p1 1014M 292M 723M 29% /boot tmpfs 364M 96K 364M 1% /run/user/0 /dev/sr0 9.0G 9.0G 0 100% /run/media/root/RHEL-9-2-0-BaseOS-x86_64 /dev/mapper/vg0-lv01 15G 140M 15G 1% /date
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逻辑卷缩容
逻辑卷缩容步骤与扩容刚好相反，先缩小文件系统大小，在缩小逻辑卷大小，根据需要是否缩减卷组大小，将物理卷中物理设备移除。
XFS文件系统不支持缩容。下面以ext4系统为例。
文件系统缩容
卸载文件系统 [root@rhce ~]# umount /date1 检查磁盘是否存在错误 [root@rhce ~]# e2fsck -f /dev/vg0/lv02 e2fsck 1.46.5 (30-Dec-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/vg0/lv02: 11/128000 files (0.0% non-contiguous), 12890/512000 blocks 设定文件系统大小 [root@rhce ~]# resize2fs /dev/vg0/lv02 500M resize2fs 1.46.5 (30-Dec-2021) Resizing the filesystem on /dev/vg0/lv02 to 128000 (4k) blocks. The filesystem on /dev/vg0/lv02 is now 128000 (4k) blocks long.
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逻辑卷缩容
使用lvresize命令重新设置大小
[root@rhce ~]# lvresize -L 500M /dev/vg0/lv02
File system ext4 found on vg0/lv02.
File system size (500.00 MiB) is equal to the requested size (500.00 MiB).
File system reduce is not needed, skipping.
Size of logical volume vg0/lv02 changed from 1.95 GiB (500 extents) to 500.00 MiB (125 extents).
Logical volume vg0/lv02 successfully resized.
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检查是否缩容成功
[root@rhce ~]# mount /dev/vg0/lv02 /date1
[root@rhce ~]# df -h /dev/vg0/lv02
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg0-lv02 475M 24K 440M 1% /date1
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卷组缩容
使用vgreduce命令从卷组中移除物理卷
[root@rhce ~]# vgreduce vg0 /dev/sdc
Removed "/dev/sdc" from volume group "vg0"
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删除逻辑卷
删除逻辑卷
使用lvremove命令删除逻辑卷
[root@rhce ~]# lvremove /dev/vg0/lv01
Do you really want to remove active logical volume vg0/lv01? [y/n]: y
Logical volume "lv01" successfully removed.
[root@rhce ~]# lvremove /dev/vg0/lv02
Do you really want to remove active logical volume vg0/lv02? [y/n]: y
Logical volume "lv02" successfully removed.
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删除卷组
使用vgremove命令删除卷组
[root@rhce ~]# vgremove vg0
Volume group "vg0" successfully removed
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删除物理卷
使用pvremove命令来移除PV。
[root@rhce ~]# pvremove /dev/sd{a..c}
Labels on physical volume "/dev/sda" successfully wiped.
Labels on physical volume "/dev/sdb" successfully wiped.
Labels on physical volume "/dev/sdc" successfully wiped.
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（3）LVM命令汇总
| 命令 | 作用 |
|---|---|
pvs | 显示物理卷信息 |
pvdisplay | 显示物理卷的各种属性 |
pvmove | 将PE从一个物理卷移动到另一个物理卷 |
pvcreate | 初始化物理卷供LVM使用 |
pvremove | 从物理卷中删除LVM标签 |
vgs | 显示卷组信息 |
vgdisplay | 显示卷组的各种属性 |
vgcreate | 创建卷组 |
vgremove | 删除卷组 |
vgreduce | 从卷组中移除物理卷 |
vgextend | 往卷组添加物理卷 |
lvs | 显示逻辑卷信息 |
lvdisplay | 显示逻辑卷的各种属性 |
lvcreate | 创建一个逻辑卷 |
lvremove | 删除逻辑卷 |
lvreduce | 减少逻辑卷的大小 |
lvextend | 增加逻辑卷的大小 |
lvresize | 调整逻辑卷的大小 |
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