2021-05-12 14:32:11
Linux下通過LVM對磁碟進行動態擴容 (Linux的邏輯卷)
2020-06-16 16:32:41
1 LVM是什麼
1.1 概念解釋
LVM(Logical Volume Manager), 邏輯卷管理, 是一種將一至多個硬碟的分割區在邏輯上進行組合, 當成一個大硬碟來使用。
當硬碟空間不足時, 可以動態地新增其它硬碟的分割區到已有的捲組中 —— 磁碟空間的動態管理。
1.2 為什麼用LVM
LVM通常用於裝備大量磁碟的系統, 比如伺服器中的磁碟陣列.
但LVM同樣適用於僅有一、兩塊硬碟的小系統.
1.2.1 不使用LVM時的擴容思路
傳統的檔案系統是基於分割區的, 一個檔案系統對應一個分割區, 這種方式比較直觀, 但不易改變:
(1) 不同的分割區相互獨立, 單獨的檔案不能跨分割區儲存, 容易出現硬碟的利用率不均衡;
(2) 當一個檔案系統/分割區裝滿時, 是不能對其進行擴容的, 只能採用重新分割區/建立檔案系統, 重新分割區會丟失資料, 就要:
① 做資料的遷移和備份;
② 或者把分割區中的資料移到另一個更大的分割區中;
③ 或者採用符號連線的方式使用其它分割區的空間 —— 都非常麻煩;(3) 如果要把硬碟上的多個分割區合併在一起使用, 只能採用重新分割區的方式, —— 需要做好資料的備份與恢復.
1.2.2 使用LVM時的擴容思路
使用LVM時技術時, 情況有所不同:
(1) 硬碟的多個分割區由LVM統一管理為捲組, 可以很輕鬆地加入或移走某個分割區 —— 也就是擴大或減小卷組的可用容量, 充分利用硬碟空間;
(2) 檔案系統建立在邏輯卷上, 而邏輯卷可以根據需要改變大小(在捲組容量範圍內)以滿足要求;
(3) 檔案系統建立在LVM上, 可以跨分割區儲存存取, 更加方便;
強烈建議對擁有多個磁碟的系統, 使用LVM管理磁碟.
1.3 名詞解釋
PV(Physical Volume): 物理卷, 處於LVM最底層, 可以是物理硬碟或者分割區;
PP(Physical Extend): 物理區域, PV中可以用於分配的最小儲存單元, 可以在建立PV的時候指定, 如1M, 2M, 4M, 8M…..組成同一VG中所有PV的PE大小應該相同;
VG(Volume Group): 卷組, 建立在PV之上, 可以含有一個到多個PV;
LV(Logical Volume): 邏輯卷, 建立在VG之上, 相當於原來分割區的概念, 不過大小可以動態改變.
2 普通的掛載磁碟方法
2.1 建立分割區的主要操作
(1) 檢視分割區情況 - fdisk -l
[root@localhost ~]# fdisk -l Disk /dev/sda: 299.0 GB, 298999349248 bytes # 磁碟/dev/sda 255 heads, 63 sectors/track, 36351 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x4d69fe0e Device Boot Start End Blocks Id System /dev/sda1 * 1 26 204800 83 Linux # 分為2個區, sda1 Partition 1 does not end on cylinder boundary. /dev/sda2 26 36352 291785728 8e Linux LVM # sda2 # 磁碟/dev/sdb沒有分割區 Disk /dev/sdb: 4000.0 GB, 3999999721472 bytes 255 heads, 63 sectors/track, 486305 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 ......
(2) 檢視已有磁碟 - lsblk
[root@localhost ~]# lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 278.5G 0 disk ├─sda1 8:1 0 200M 0 part /boot └─sda2 8:2 0 278.3G 0 part └─VolGroup-LogVol (dm-0) 253:0 0 1.9T 0 lvm / # LVM型別的分割區 sdb 8:32 0 3.7T 0 disk # 還沒有分割區的新磁碟
(3) 對新磁碟進行分割區 - fdisk /dev/sdb
[root@localhost ~]# fdisk /dev/sdb
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0xf91f8c4c.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
WARNING: The size of this disk is 4.0 TB (4000225165312 bytes).
DOS partition table format can not be used on drives for volumes
larger than (2199023255040 bytes) for 512-byte sectors. Use parted(1) and GUID
partition table format (GPT).
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').
Command (m for help): n # n 表示新建分割區
Command action
e extended
p primary partition (1-4)
p # p 表示分割區型別為主分割區, 主分割區只有1-4種選擇
Partition number (1-4): 1 # 主分割區的編號
First cylinder (1-486333, default 1): # 開始磁區號, 直接回車, 使用預設值1
Using default value 1
# 結束磁區號, 使用預設值 --- 這裡只載入了新磁碟的一半(2T), 所以還需要再次建立分割區/dev/sdb2使用剩下的一半.
Last cylinder, +cylinders or +size{K,M,G} (1-267349, default 267349):
Using default value 267349
Command (m for help): w # 將上述設定寫入分割區表並退出
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
(4) 再次檢視分割區情況 - fdisk -l
多出來一個/dev/sdb1的區, 這個1就是之前主分割區之後指定的分割區編號.
[root@localhost ~]# fdisk -l Disk /dev/sda: 299.0 GB, 298999349248 bytes 255 heads, 63 sectors/track, 36351 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x4d69fe0e Device Boot Start End Blocks Id System /dev/sda1 * 1 26 204800 83 Linux Partition 1 does not end on cylinder boundary. /dev/sda2 26 36352 291785728 8e Linux LVM # /dev/sdb磁碟: Disk /dev/sdb: 4000.0 GB, 3999999721472 bytes 255 heads, 63 sectors/track, 486305 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x8f3043b5 # 多出來的分割區/dev/sdb1 Device Boot Start End Blocks Id System /dev/sdb1 1 267349 2147480811 83 Linux ......
(5) 檢視當前分割區表中的分割區資訊 - cat /proc/partitions
[root@localhost ~]# cat /proc/partitions major minor #blocks name 8 0 291991552 sda 8 1 204800 sda1 8 2 291785728 sda2 8 32 3906249728 sdb # 新增的新磁碟 8 33 2147480811 sdb1 # 建立的新分割區 253 0 2046660608 dm-0
如果建立完之後，cat /proc/partitions 檢視不到對應的分割區, 使用 parprobe 重新整理命令即可:
[root@localhost ~]# partprobe /dev/sdc
2.2 格式化新分割區
(1) 格式化新分割區 - mkfs -t
這裡建議將新分割區格式化為ext4檔案型別, 還有ext2, ext3等檔案型別, 區別請參考部落格 ext2、ext3與ext4的區別 .
[root@localhost ~]# mkfs -t ext4 /dev/sdb1
mke2fs 1.41.12 (17-May-2010)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
134217728 inodes, 536870202 blocks
26843510 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
16384 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968,
102400000, 214990848, 512000000
Writing inode tables: 8874/16384
(2) 等待一小會後, 將出現下述提示, 說明格式化完成:
Writing inode tables: done Creating journal (32768 blocks): done Writing superblocks and filesystem accounting information: done This filesystem will be automatically checked every 26 mounts or 180 days, whichever comes first. Use tune2fs -c or -i to override.
2.3 掛載新分割區
(1) 建立目錄, 並將 /dev/sdb1掛在到該目錄下:
[root@localhost /]# mkdir data && cd /data [root@localhost data]# mount /dev/sdc1 /data1
(2) 檢視掛載是否成功:
[root@localhost data]# df -l Filesystem 1K-blocks Used Available Use% Mounted on /dev/mapper/VolGroup-LogVol 286901696 18601728 253726196 7% / tmpfs 66020980 0 66020980 0% /dev/shm /dev/sda1 495844 33476 436768 8% /boot # 掛載成功: /dev/sdb1 2113784984 202776 2006208168 1% /data
2.4 設定開機自動掛載
編輯檔案 /etc/fstab:
[root@localhost data]# vim /etc/fstab # 檔案內容如下: # /etc/fstab # Created by anaconda on Wed Sep 12 10:41:40 2018 # # 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 # /dev/mapper/VolGroup-LogVol / ext4 defaults 1 1 /dev/sdb1 /data ext4 defaults 1 1 UUID=22b1d425-d050-43c3-a735-06d48bbb9051 /boot ext4 defaults 1 2 tmpfs /dev/shm tmpfs defaults 0 0 devpts /dev/pts devpts gid=5,mode=620 0 0 sysfs /sys sysfs defaults 0 0 proc /proc proc defaults 0 0
3 LVM方式掛載磁碟 - 推薦
3.1 檢視磁碟容量資訊
[root@localhost ~]# df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/VG-LogVol 1.9T 1.8T 61G 97% / # LVM卷組-邏輯卷 tmpfs 63G 0 63G 0% /dev/shm /dev/sda1 485M 40M 421M 9% /boot
3.2 檢視磁碟磁區資訊
[root@localhost ~]# fdisk -l Disk /dev/sda: 299.0 GB, 298999349248 bytes # 磁碟/dev/sda 255 heads, 63 sectors/track, 36351 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x4d69fe0e Device Boot Start End Blocks Id System /dev/sda1 * 1 26 204800 83 Linux # 分為2個區, sda1 Partition 1 does not end on cylinder boundary. /dev/sda2 26 36352 291785728 8e Linux LVM # LVM型別的sda2 # 新新增的磁碟/dev/sdb, 沒有分割區 Disk /dev/sdb: 4000.0 GB, 3999999721472 bytes 255 heads, 63 sectors/track, 486305 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 # LVM格式的捲組資訊: Disk /dev/mapper/VolGroup-LogVol: 4294 MB, 4294967296 bytes 255 heads, 63 sectors/track, 522 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000
3.3 建立分割區
[root@localhost ~]# fdisk /dev/sdb
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0x5b3d66ba.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
WARNING: The size of this disk is 4.0 TB (3999999721472 bytes).
DOS partition table format can not be used on drives for volumes
larger than (2199023255040 bytes) for 512-byte sectors. Use parted(1) and GUID
partition table format (GPT).
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').
Command (m for help): n # 新增分割區
Command action
e extended
p primary partition (1-4)
p # 新增主分割區
Partition number (1-4): 1 # 1號主分割區, 即/dev/sdb1
First cylinder (1-486305, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-267349, default 267349): 486305
Value out of range.
Last cylinder, +cylinders or +size{K,M,G} (1-267349, default 267349):
Using default value 267349
Command (m for help): n # 繼續新增分割區
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 2 # 2號主分割區, 即/dev/sdc2
First cylinder (267350-486305, default 267350):
Using default value 267350
Last cylinder, +cylinders or +size{K,M,G} (267350-486305, default 486305):
Using default value 486305
Command (m for help): p # 列印分割區資訊:
Disk /dev/sdb: 4000.0 GB, 3999999721472 bytes
255 heads, 63 sectors/track, 486305 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x5b3d66ba
Device Boot Start End Blocks Id System
/dev/sdb1 1 267349 2147480811 83 Linux
/dev/sdb2 267350 486305 1758764070 83 Linux
Command (m for help): t # 轉換型別
Partition number (1-4): 1
Partition number (1-4): 1 # 修改/dev/sdb1為Linux LVM型別:
Hex code (type L to list codes): L # 檢視可用型別:
0 Empty 24 NEC DOS 81 Minix / old Lin bf Solaris
1 FAT12 39 Plan 9 82 Linux swap / So c1 DRDOS/sec (FAT-
2 XENIX root 3c PartitionMagic 83 Linux c4 DRDOS/sec (FAT-
3 XENIX usr 40 Venix 80286 84 OS/2 hidden C: c6 DRDOS/sec (FAT-
4 FAT16 <32M 41 PPC PReP Boot 85 Linux extended c7 Syrinx
5 Extended 42 SFS 86 NTFS volume set da Non-FS data
6 FAT16 4d QNX4.x 87 NTFS volume set db CP/M / CTOS / .
7 HPFS/NTFS 4e QNX4.x 2nd part 88 Linux plaintext de Dell Utility
8 AIX 4f QNX4.x 3rd part 8e Linux LVM df BootIt
9 AIX bootable 50 OnTrack DM 93 Amoeba e1 DOS access
a OS/2 Boot Manag 51 OnTrack DM6 Aux 94 Amoeba BBT e3 DOS R/O
b W95 FAT32 52 CP/M 9f BSD/OS e4 SpeedStor
c W95 FAT32 (LBA) 53 OnTrack DM6 Aux a0 IBM Thinkpad hi eb BeOS fs
e W95 FAT16 (LBA) 54 OnTrackDM6 a5 FreeBSD ee GPT
f W95 Ext'd (LBA) 55 EZ-Drive a6 OpenBSD ef EFI (FAT-12/16/
10 OPUS 56 Golden Bow a7 NeXTSTEP f0 Linux/PA-RISC b
11 Hidden FAT12 5c Priam Edisk a8 Darwin UFS f1 SpeedStor
12 Compaq diagnost 61 SpeedStor a9 NetBSD f4 SpeedStor
14 Hidden FAT16 <3 63 GNU HURD or Sys ab Darwin boot f2 DOS secondary
16 Hidden FAT16 64 Novell Netware af HFS / HFS+ fb VMware VMFS
17 Hidden HPFS/NTF 65 Novell Netware b7 BSDI fs fc VMware VMKCORE
18 AST SmartSleep 70 DiskSecure Mult b8 BSDI swap fd Linux raid auto
1b Hidden W95 FAT3 75 PC/IX bb Boot Wizard hid fe LANstep
1c Hidden W95 FAT3 80 Old Minix be Solaris boot ff BBT
1e Hidden W95 FAT1
Hex code (type L to list codes): 8e # 修改為8e, 即Linux LVM型別
Changed system type of partition 1 to 8e (Linux LVM)
Command (m for help): t
Partition number (1-4): 2 # 修改/dev/sdc2為Linux LVM型別
Hex code (type L to list codes): 8e
Changed system type of partition 2 to 8e (Linux LVM)
Command (m for help): p # 再次檢視相關資訊:
Disk /dev/sdc: 4000.0 GB, 3999999721472 bytes
255 heads, 63 sectors/track, 486305 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x5b3d66ba
Device Boot Start End Blocks Id System
/dev/sdb1 1 267349 2147480811 8e Linux LVM # Id已改變
/dev/sdb2 267350 486305 1758764070 8e Linux LVM
Command (m for help): w # 儲存並退出
The partition table has been altered! # 修改成功
Calling ioctl() to re-read partition table.
Syncing disks.
3.4 建立物理卷
[root@localhost ~]# pvcreate /dev/sdb1 Physical volume "/dev/sdb1" successfully created [root@localhost ~]# pvcreate /dev/sdb2 Physical volume "/dev/sdb2" successfully created
3.5 擴充套件卷組
# 檢視已有捲組, 發現該卷組就是需要擴容的捲組, 就不必再次建立卷組, 而是直接擴充套件卷組即可: [root@localhost ~]# vgs VG #PV #LV #SN Attr VSize VFree VolGroup 2 2 0 wz--n- 1.91t 0 # 擴充套件卷組: [root@localhost ~]# vgextend VolGroup /dev/sdb1 Volume group "VolGroup" successfully extended [root@localhost ~]# vgextend VolGroup /dev/sdb2 Volume group "VolGroup" successfully extended
說明: 如果出現下述無法掛載物理磁碟到卷組中的資訊, 說明這塊物理磁碟已經掛載了, 需要先解除安裝, 然後再執行建立分割區+卷組的操作:
[root@localhost /]# vgextend VolGroup /dev/sdb1 No physical volume label read from /dev/sdb1 Physical volume /dev/sdb1 not found Can't open /dev/sdb1 exclusively. Mounted filesystem? Unable to add physical volume '/dev/sdb1' to volume group 'VolGroup'.
3.6 擴充套件邏輯卷
# 擴充套件邏輯卷, 即擴容: [root@localhost ~]# lvextend -l +100%FREE /dev/mapper/VolGroup-LogVol Extending logical volume lv_root to 5.54 TiB Logical volume lv_root successfully resized # 上述命令是將所有的空閒空間都擴容到邏輯卷中, 也可指定擴容的大小: lvextend -l +100G /dev/mapper/VolGroup-LogVol
3.7 檢視磁碟卷組資訊
[root@localhost ~]# lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 278.5G 0 disk ├─sda1 8:1 0 500M 0 part /boot └─sda2 8:2 0 278G 0 part ├─VolGroup-LogVol (dm-0) 253:0 0 5.6T 0 lvm / sdb 8:16 0 1.6T 0 disk └─sdb1 8:17 0 1.6T 0 part └─VolGroup-LogVol (dm-0) 253:0 0 5.6T 0 lvm / sdc 8:32 0 3.7T 0 disk ├─sdc1 8:33 0 2T 0 part │ └─VolGroup-LogVol (dm-0) 253:0 0 5.6T 0 lvm / └─sdc2 8:34 0 1.7T 0 part └─VolGroup-LogVol (dm-0) 253:0 0 5.6T 0 lvm /
3.8 調整檔案系統的大小
# CentOS 7重新讀取磁碟大小: [root@localhost ~]# xfs_growfs /dev/mapper/VolGroup-LogVol xfs_growfs: /dev/mapper/VolGroup-LogVol is not a mounted XFS filesystem # CentOS 6.5重新讀取磁碟大小: # ext4格式, resize2fs會遍歷整個磁碟, 速度比較慢, 但是不影響讀寫資料, 可以令其在後台執行. [root@localhost ~]# resize2fs /dev/mapper/VolGroup-LogVol resize2fs 1.41.12 (17-May-2010) Filesystem at /dev/mapper/VolGroup-LogVol is mounted on /; on-line resizing required old desc_blocks = 122, new_desc_blocks = 355 Performing an on-line resize of /dev/mapper/VolGroup-lv_root to 1487098880 (4k) blocks. # 等了差不多20分鐘, 出來了下面這貨: The filesystem on /dev/mapper/VolGroup-LogVol is now 1487098880 blocks long. # 趕緊看下擴容成果吧: [root@localhost ~]# df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/VolGroup-LogVol 5.5T 1.8T 3.5T 34% / # 擴容成功 tmpfs 63G 0 63G 0% /dev/shm /dev/sda1 485M 40M 421M 9% /boot
3.9 附錄 - 建立卷組
對應 [3.5] 節的擴充套件卷組, 如果捲組不存在, 則需要建立之. 下述VolGroup是捲組名稱.
vgcreate VolGroup /dev/sdb1 # 建立邏輯卷, 名稱為: mylv. (作業系統中將產生: /dev/VolGroup/mylv目錄) # 將當前捲組中的100G空間分配到邏輯卷中 lvcreate -L 100G VolGroup -n mylv # 或將當前捲組中的所有空閒空間全都分配到邏輯卷中: lvcreate -l +100%FREE VolGroup -n mylv # 格式化邏輯卷組: mkfs -t ext4 /dev/VolGroup/mylv # 掛載卷組到指定目錄下, 如果是掛載到根目錄, 則無需向/etc/fstab檔案中新增啟動項. mount -t ext4 /dev/VolGroup/mylv /data
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