Linux----LVM擴容磁盤空間

Linux系統LVM擴容一個分區相對於Windows來講沒有那麼直觀，可是熟悉命令後，擴容起來也是蠻方便的。

 

擴容場景以下：

1 [root@rhel06 ~]# df -Th
2 Filesystem            Type     Size  Used Avail Use% Mounted on
3 /dev/sda2             ext4     9.9G  2.2G  7.3G  23% /
4 tmpfs                 tmpfs    491M     0  491M   0% /dev/shm
5 /dev/sda1             ext4     194M   29M  155M  16% /boot
6 /dev/sr0              iso9660  3.6G  3.6G     0 100% /mnt
7 /dev/mapper/VG001-lv1 ext4     2.0G   67M  1.9G   4% /lv1

現有一個lvm分區lv1容量2G，但願擴容此分區空間

 

 1 [root@rhel06 home]# cat /proc/partitions 
 2 major minor  #blocks  name
 3 
 4    8        0   20971520 sda
 5    8        1     204800 sda1
 6    8        2   10485760 sda2
 7    8        3    2097152 sda3
 8    8        4          1 sda4
 9    8        5    2103487 sda5
10  253        0    2097152 dm-0

查看partitions  獲取當前分區狀況和磁盤總空間狀況。須要計算20971520-204800-10485760-2097152-2103487-1=6080320，約6G的未使用空間。（dm-0是一個lv分區）

固然使用這種手動方式獲取未分區空間太過麻煩。能夠用這個shell來完成大量的計算

 1 [root@rhel06 home]# cat sda.sh 
 2 #!/bin/bash
 3 total=$(grep 'sda$' /proc/partitions |awk '{print $3}');
 4 used=0 
 5 for i in $(grep 'sda[[:digit:]]\+$' /proc/partitions |awk '{print $3}' |xargs) 
 6 do
 7 used=$(( used + i ));
 8 done
 9 echo $((( total - used ) / 1024 )) "MB"
10 [root@rhel06 home]# ./sda.sh 
11 5937 MB

 

接下來執行具體的分區步驟：

1、劃分一個新分區並格式化

 1 [root@rhel06 ~]# fdisk /dev/sda
 2 
 3 Command (m for help): p 
 4 
 5 Disk /dev/sda: 21.5 GB, 21474836480 bytes
 6 255 heads, 63 sectors/track, 2610 cylinders
 7 Units = cylinders of 16065 * 512 = 8225280 bytes
 8 Sector size (logical/physical): 512 bytes / 512 bytes
 9 I/O size (minimum/optimal): 512 bytes / 512 bytes
10 Disk identifier: 0x00029f55
11 
12    Device Boot      Start         End      Blocks   Id  System
13 /dev/sda1   *           1          26      204800   83  Linux
14 Partition 1 does not end on cylinder boundary.
15 /dev/sda2              26        1332    10485760   83  Linux
16 /dev/sda3            1332        1593     2097152   82  Linux swap / Solaris
17 /dev/sda4            1593        2610     8176089    5  Extended
18 /dev/sda5            1593        1854     2103487+  8e  Linux LVM
19 
20 Command (m for help): n   #新建分區，因爲我已新建了四個分區（主分區和邏輯分區），因此這裏只能新建擴展分區，並無出現分區類型選項 21 First cylinder (1855-2610, default 1855):      #開始點，直接回車便可 22 Using default value 1855
23 Last cylinder, +cylinders or +size{K,M,G} (1855-2610, default 2610): +2G    #+2G，劃分一個2G的新分區 24 
25 Command (m for help): p
26 
27 Disk /dev/sda: 21.5 GB, 21474836480 bytes
28 255 heads, 63 sectors/track, 2610 cylinders
29 Units = cylinders of 16065 * 512 = 8225280 bytes
30 Sector size (logical/physical): 512 bytes / 512 bytes
31 I/O size (minimum/optimal): 512 bytes / 512 bytes
32 Disk identifier: 0x00029f55
33 
34    Device Boot      Start         End      Blocks   Id  System
35 /dev/sda1   *           1          26      204800   83  Linux
36 Partition 1 does not end on cylinder boundary.
37 /dev/sda2              26        1332    10485760   83  Linux
38 /dev/sda3            1332        1593     2097152   82  Linux swap / Solaris
39 /dev/sda4            1593        2610     8176089    5  Extended
40 /dev/sda5            1593        1854     2103487+  8e  Linux LVM
41 /dev/sda6            1855        2116     2104483+  83  Linux
42 
43 Command (m for help): w   #保存退出

1 [root@rhel06 ~]# partprobe   #不要忘了刷新分區表，虛擬機仍是須要重啓才能刷新。

1 [root@rhel06 ~]# mkfs.ext4 /dev/sda6  #格式化

 

2、轉換sda6分區爲pv

 1 [root@rhel06 ~]# pvcreate /dev/sda6    #轉換sda6分區
 2   dev_is_mpath: failed to get device for 8:6
 3   Physical volume "/dev/sda6" successfully created
 4 [root@rhel06 ~]# pvdisplay      #查看系統全部pv，這裏sda6已成功轉換
 5   --- Physical volume ---
 6   PV Name               /dev/sda5
 7   VG Name               VG001
 8   PV Size               2.01 GiB / not usable 2.19 MiB
 9   Allocatable           yes 
10   PE Size               4.00 MiB
11   Total PE              513
12   Free PE               1
13   Allocated PE          512
14   PV UUID               dSHFLX-9Lui-0ZDb-6J2g-pp6A-azuX-vg5yGV
15    
16   "/dev/sda6" is a new physical volume of "2.01 GiB"
17   --- NEW Physical volume ---
18   PV Name               /dev/sda6
19   VG Name               
20   PV Size               2.01 GiB
21   Allocatable           NO
22   PE Size               0   
23   Total PE              0
24   Free PE               0
25   Allocated PE          0
26   PV UUID               TEGKht-876S-8MMd-vWkX-rjeI-4UqG-JqRsT2

 

3、添加新pv到vg

 1 [root@rhel06 ~]# vgdisplay |grep Name    #查看當前vg名稱
 2   VG Name               VG001
 3 [root@rhel06 ~]# vgextend VG001 /dev/sda6  #添加「sda6」pv到此vg
 4   Volume group "VG001" successfully extended
 5 [root@rhel06 ~]# vgdisplay     #查看vg詳情，能夠看到vg已經擴容到4g
 6   --- Volume group ---
 7   VG Name               VG001
 8   System ID             
 9   Format                lvm2
10   Metadata Areas        2
11   Metadata Sequence No  3
12   VG Access             read/write
13   VG Status             resizable
14   MAX LV                0
15   Cur LV                1
16   Open LV               1
17   Max PV                0
18   Cur PV                2
19   Act PV                2
20   VG Size               4.01 GiB
21   PE Size               4.00 MiB
22   Total PE              1026
23   Alloc PE / Size       512 / 2.00 GiB
24   Free  PE / Size       514 / 2.01 GiB
25   VG UUID               qG18Fp-agAP-gaTp-0crS-Ughm-UilM-2ZftQt

 

4、調整lv1容量

1 [root@rhel06 ~]# lvextend -L 4G /dev/VG001/lv1    #調整lv1分區容量爲4G，原來是2G
2   Extending logical volume lv1 to 4.00 GiB
3   Logical volume lv1 successfully resized
4 [root@rhel06 ~]# resize2fs /dev/VG001/lv1    #執行重設大小，對當前lv1有效
5 resize2fs 1.41.12 (17-May-2010)
6 Filesystem at /dev/VG001/lv1 is mounted on /lv1; on-line resizing required
7 old desc_blocks = 1, new_desc_blocks = 1
8 Performing an on-line resize of /dev/VG001/lv1 to 1048576 (4k) blocks.
9 The filesystem on /dev/VG001/lv1 is now 1048576 blocks long.

 

5、到此設置已完成，df命令查看已擴容到4G

1 [root@rhel06 ~]# df -h
2 Filesystem             Size  Used Avail Use% Mounted on
3 /dev/sda2              9.9G  2.2G  7.3G  23% /
4 tmpfs                  491M     0  491M   0% /dev/shm
5 /dev/sda1              194M   29M  155M  16% /boot
6 /dev/sr0               3.6G  3.6G     0 100% /mnt
7 /dev/mapper/VG001-lv1  4.0G   68M  3.7G   2% /lv1

 

6、新增lv分區

 [root@rhel06 ~]# lvcreate -L 4G -n lv0data lv1 #在lv1邏輯卷新增lv0data分區   -L指定大小   -n指定名稱

 

問題1：執行partprobe刷新分區表時會出現如下報錯：

[root@rhel06 ~]# partprobe
Warning: WARNING: the kernel failed to re-read the partition table on /dev/sda (設備或資源忙).  As a result, it may not reflect all of your changes until after reboot.

這個問題貌似只存在於虛擬機上面，物理機上並無發現這個問題。重啓虛擬機便可。

 

問題2：fdisk能夠查看到sda5分區，可是使用mkfs格式化是提示「沒有這個文件或目錄」，那是分區表沒有刷新或者刷新失敗，刷新步驟可參考上一個問題。

 1    Device Boot      Start         End      Blocks   Id  System
 2 /dev/sda1   *           1          26      204800   83  Linux
 3 Partition 1 does not end on cylinder boundary.
 4 /dev/sda2              26        1332    10485760   83  Linux
 5 /dev/sda3            1332        1593     2097152   82  Linux swap / Solaris
 6 /dev/sda4            1593        2610     8176089    5  Extended
 7 /dev/sda5            1593        1854     2103487+  83  Linux
 8 [root@rhel06 ~]# mkfs.ext4 /dev/sda5
 9 mke2fs 1.41.12 (17-May-2010)
10 沒法對 /dev/sda5 進行 stat 調用 --- 沒有那個文件或目錄