author：石魯坤
因爲部署項目過程中服務器改變使用用途，將數據庫服務器改用爲應用服務器，之前的分區規劃swap佔用了15G,home目錄20G,考慮應用服務器對swap應用有限，造成資源浪費，所以將swap分區減小到5G，將home增加10G
磁盤應用了邏輯分區，記錄操作過程如下
[root@shiyou ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/centos-root 185G 2.0G 183G 2% /
devtmpfs 16G 0 16G 0% /dev
tmpfs 16G 0 16G 0% /dev/shm
tmpfs 16G 11M 16G 1% /run
tmpfs 16G 0 16G 0% /sys/fs/cgroup
/dev/sda2 1014M 135M 880M 14% /boot
/dev/sda1 1022M 9.8M 1013M 1% /boot/efi
/dev/sdb1 1.1T 265M 1.1T 1% /app
/dev/mapper/centos-home 20G 33M 20G 1% /home
tmpfs 3.1G 0 3.1G 0% /run/user/0
[root@shiyou ~]# free -g
total used free shared buff/cache available
Mem: 30 1 28 0 1 29
Swap: 15 0 15
1，首先將swap分區解掛
[root@shiyou ~]# swapoff /dev/mapper/centos-swap
[root@shiyou ~]# free -g
total used free shared buff/cache available
Mem: 30 1 28 0 1 29
Swap: 0 0 0
此時swap分區已經顯示爲0
2，壓縮 /dev/mapper/centos-swap 分區
[root@shiyou ~]# lvreduce -L -10240M /dev/mapper/centos-swap
WARNING: Reducing active logical volume to 6.00 GiB.
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce centos/swap? [y/n]: Y
Size of logical volume centos/swap changed from 16.00 GiB (4096 extents) to 6.00 GiB (1536 extents).
Logical volume centos/swap successfully resized.
[root@shiyou ~]# mkswap /dev/mapper/centos-swap
mkswap: /dev/mapper/centos-swap: warning: wiping old swap signature.
Setting up swapspace version 1, size = 11534332 KiB
no label, UUID=35749ea4-428c-47fb-9384-5fdbd35d4977
3，重新掛載swap分區
[root@shiyou ~]# swapon /dev/mapper/centos-swap
[root@shiyou ~]# free -g
total used free shared buff/cache available
Mem: 30 1 28 0 1 29
Swap: 5 0 5
此時swap分區已經變成了5G,接下來我們將10G空間增加到home下
4，檢查free的PE,將空閒出的空間增加到home分區
[root@shiyou ~]# vgdisplay
--- Volume group ---
VG Name centos
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 6
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 3
Open LV 3
Max PV 0
Cur PV 1
Act PV 1
VG Size 220.58 GiB
PE Size 4.00 MiB
Total PE 56469
Alloc PE / Size 53908 / <210.58 GiB
Free PE / Size 2561 / 10.00 GiB
VG UUID 8l07mB-oXcz-WwDx-Rl3i-tRXX-D7gM-tIokDr
此時看到Free PE / Size 2561 / 10.00 GiB
[root@shiyou ~]# lvresize -L +10G /dev/mapper/centos-home
[root@shiyou ~]# vgdisplay
--- Volume group ---
VG Name centos
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 16
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 3
Open LV 3
Max PV 0
Cur PV 1
Act PV 1
VG Size 220.58 GiB
PE Size 4.00 MiB
Total PE 56469
Alloc PE / Size 56469 / 220.58 GiB
Free PE / Size 0 / 0
VG UUID 8l07mB-oXcz-WwDx-Rl3i-tRXX-D7gM-tIokDr
此時所有的空閒空間到/dev/mapper/centos-home
[root@shiyou ~]# lvdisplay
--- Logical volume ---
LV Path /dev/centos/home
LV Name home
VG Name centos
LV UUID xXZju5-tSek-qsTG-sInL-gd2C-L8z8-rcZCcw
LV Write Access read/write
LV Creation host, time bogon, 2019-06-17 09:23:33 +0800
LV Status available
# open 1
LV Size 30.00 GiB
Current LE 7681
Segments 3
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:2
5,增加home文件系統的容量,這有有個報錯，一併記錄
[root@shiyou ~]# resize2fs /dev/centos/home
resize2fs 1.42.9 (28-Dec-2013)
resize2fs: Bad magic number in super-block while trying to open /dev/centos/home
Couldn't find valid filesystem superblock.
報錯了，打不開分區
[root@shiyou ~]# mount|grep home 或者使用(df -T)
/dev/mapper/centos-home on /home type xfs (rw,relatime,seclabel,attr2,inode64,sunit=128,swidth=128,noquota)
發現/dev/mapper/centos-home 是xfs文件系統，不是ext
[root@shiyou ~]# xfs_growfs /dev/mapper/centos-home
meta-data=/dev/mapper/centos-home isize=512 agcount=16, agsize=327680 blks
= sectsz=4096 attr=2, projid32bit=1
= crc=1 finobt=0 spinodes=0
data = bsize=4096 blocks=5242880, imaxpct=25
= sunit=16 swidth=16 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal bsize=4096 blocks=2560, version=2
= sectsz=4096 sunit=1 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 5242880 to 7669760
[root@shiyou ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/centos-root 185G 2.6G 182G 2% /
devtmpfs 16G 0 16G 0% /dev
tmpfs 16G 0 16G 0% /dev/shm
tmpfs 16G 11M 16G 1% /run
tmpfs 16G 0 16G 0% /sys/fs/cgroup
/dev/sda2 1014M 135M 880M 14% /boot
/dev/sda1 1022M 9.8M 1013M 1% /boot/efi
/dev/sdb1 1.1T 265M 1.1T 1% /app
/dev/mapper/centos-home 30G 55M 30G 1% /home
tmpfs 3.1G 0 3.1G 0% /run/user/0
檢查可以看到home目錄已經成功增加到30G
整個拓展空間過程因爲磁盤使用了lvm，無需系統重啓，即可動態解決