author：石鲁坤
因为部署项目过程中服务器改变使用用途，将数据库服务器改用为应用服务器，之前的分区规划swap占用了15G,home目录20G,考虑应用服务器对swap应用有限，造成资源浪费，所以将swap分区减小到5G，将home增加10G
磁盘应用了逻辑分区，记录操作过程如下
[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，首先将swap分区解挂
[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
此时swap分区已经显示为0
2，压缩 /dev/mapper/centos-swap 分区
[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，重新挂载swap分区
[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
此时swap分区已经变成了5G,接下来我们将10G空间增加到home下
4，检查free的PE,将空闲出的空间增加到home分区
[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
此时看到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
此时所有的空闲空间到/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文件系统的容量,这有有个报错，一并记录
[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.
报错了，打不开分区
[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)
发现/dev/mapper/centos-home 是xfs文件系统，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
检查可以看到home目录已经成功增加到30G
整个拓展空间过程因为磁盘使用了lvm，无需系统重启，即可动态解决