扩展swap分区

free -h命令查看内存使用空间。
total        used        free      shared  buff/cache     available
总大小      使用的大小   空闲      共享    缓冲区/缓存   真正可用内存

yum install gdisk -y
gdisk /dev/sdb
1、分一个新区，给swap
n 添加新的分区
p 显示分区表
2、mkswap /dev/vdb3 (格式化成swap格式）
3、swapon /dev/vdb3(激活/swap,加入到swap分区中，临时生效）
4、vim /etc/fstab （写入自动挂载）
/dev/vdb3  swap swap defaults 0 0

注：ID为8200

具体操作过程：
[root@gz ~]# gdisk /dev/vdb
GPT fdisk (gdisk) version 0.8.10

Partition table scan:
  MBR: protective
  BSD: not present
  APM: not present
  GPT: present

Found valid GPT with protective MBR; using GPT.

Command (? for help): n
Partition number (3-128, default 3): 
First sector (34-20971486, default = 12584960) or {+-}size{KMGTP}: 
Last sector (12584960-20971486, default = 20971486) or {+-}size{KMGTP}: 
Current type is 'Linux filesystem'
Hex code or GUID (L to show codes, Enter = 8300): L
0700 Microsoft basic data  0c01 Microsoft reserved    2700 Windows RE          
3000 ONIE boot             3001 ONIE config           4100 PowerPC PReP boot   
4200 Windows LDM data      4201 Windows LDM metadata  7501 IBM GPFS            
7f00 ChromeOS kernel       7f01 ChromeOS root         7f02 ChromeOS reserved   
8200 Linux swap            8300 Linux filesystem      8301 Linux reserved      
8302 Linux /home           8400 Intel Rapid Start     8e00 Linux LVM           
a500 FreeBSD disklabel     a501 FreeBSD boot          a502 FreeBSD swap        
a503 FreeBSD UFS           a504 FreeBSD ZFS           a505 FreeBSD Vinum/RAID  
a580 Midnight BSD data     a581 Midnight BSD boot     a582 Midnight BSD swap   
a583 Midnight BSD UFS      a584 Midnight BSD ZFS      a585 Midnight BSD Vinum  
a800 Apple UFS             a901 NetBSD swap           a902 NetBSD FFS          
a903 NetBSD LFS            a904 NetBSD concatenated   a905 NetBSD encrypted    
a906 NetBSD RAID           ab00 Apple boot            af00 Apple HFS/HFS+      
af01 Apple RAID            af02 Apple RAID offline    af03 Apple label         
af04 AppleTV recovery      af05 Apple Core Storage    be00 Solaris boot        
bf00 Solaris root          bf01 Solaris /usr & Mac Z  bf02 Solaris swap        
bf03 Solaris backup        bf04 Solaris /var          bf05 Solaris /home       
bf06 Solaris alternate se  bf07 Solaris Reserved 1    bf08 Solaris Reserved 2  
bf09 Solaris Reserved 3    bf0a Solaris Reserved 4    bf0b Solaris Reserved 5  
c001 HP-UX data            c002 HP-UX service         ea00 Freedesktop $BOOT   
eb00 Haiku BFS             ed00 Sony system partitio  ed01 Lenovo system partit
Press the <Enter> key to see more codes: 82
ef00 EFI System            ef01 MBR partition scheme  ef02 BIOS boot partition 
fb00 VMWare VMFS           fb01 VMWare reserved       fc00 VMWare kcore crash p
fd00 Linux RAID            
Hex code or GUID (L to show codes, Enter = 8300): 8200
Changed type of partition to 'Linux swap'

Command (? for help): p
Disk /dev/vdb: 20971520 sectors, 10.0 GiB
Logical sector size: 512 bytes
Disk identifier (GUID): 1BB19CCA-7D82-4584-87E1-D19F495E47C4
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 20971486
Partitions will be aligned on 2048-sector boundaries
Total free space is 2014 sectors (1007.0 KiB)

Number  Start (sector)    End (sector)  Size       Code  Name
   1            2048         6293503   3.0 GiB     8300  Linux filesystem
   2         6293504        12584959   3.0 GiB     8300  Linux filesystem
   3        12584960        20971486   4.0 GiB     8200  Linux swap

Command (? for help): w

mkswap /dev/vdb3
swapon /dev/vdb3
vim /etc/fstab

重启实例后
Welcome!

-------------------------------------------------------------------------------------------------------------------------
[root@gz ~]# free -h
              total        used        free      shared  buff/cache   available
Mem:           1.8G        240M        1.2G        588K        339M        1.4G
Swap:          5.0G          0B        5.0G