Creating a Swap Partition
1. Use fdisk /dev/vda to open your disk in fdisk. (Use gdisk if you are using a disk with a GUID partition table.)
2. Press n to add a new partition. Specify start and stop cylinders and size.
3. Type t to change the partition type. If you are using fdisk, use partition type 82. If you are using gdisk, use partition type 8200.
4. Use mkswap to format the partition as swap space. Use, for instance, mkswap /dev/vda6 if the partition you have just created is /dev/vda6.
5. Type free -m . You see the amount of swap space that is currently allocated.
6. Use swapon to switch on the newly allocated swap space. If, for instance, the swap device you have just created is /dev/vda6, use swapon /dev/vda6 to activate the swap space.
7. Type free -m again. You see that the new swap space has been added to your server.
[root@rhel7 ~]# fdisk -lDisk /dev/sda: 21.5 GB, 21474836480 bytes, 41943040 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk label type: dosDisk identifier: 0x0006c7ae Device Boot Start End Blocks Id System/dev/sda1 * 2048 1026047 512000 83 Linux/dev/sda2 1026048 41943039 20458496 8e Linux LVMDisk /dev/sdb: 5368 MB, 5368709120 bytes, 10485760 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk label type: dosDisk identifier: 0x0c16d904 Device Boot Start End Blocks Id System/dev/sdb1 2048 10485759 5241856 83 LinuxDisk /dev/sdc: 2147 MB, 2147483648 bytes, 4194304 sectors ----/dev/sdc是新添加的磁盘，未分区Units = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk /dev/mapper/rhel-root: 18.8 GB, 18756927488 bytes, 36634624 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk /dev/mapper/rhel-swap: 2147 MB, 2147483648 bytes, 4194304 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytes[root@rhel7 ~]# fdisk /dev/sdc ---在/dev/sdc磁盘上划分出一个100M的Swab分区/dev/sdc1Welcome to fdisk (util-linux 2.23.2).Changes will remain in memory only, until you decide to write them.Be careful before using the write command.Device does not contain a recognized partition tableBuilding a new DOS disklabel with disk identifier 0x3990990c.Command (m for help): nPartition type: p primary (0 primary, 0 extended, 4 free) e extendedSelect (default p): pPartition number (1-4, default 1): First sector (2048-4194303, default 2048): Using default value 2048Last sector, +sectors or +size{K,M,G} (2048-4194303, default 4194303): +100M ---输入大小100M Partition 1 of type Linux and of size 100 MiB is setCommand (m for help): t Selected partition 1Hex code (type L to list all codes): L 0 Empty 24 NEC DOS 81 Minix / old Lin bf Solaris 1 FAT12 27 Hidden NTFS Win 82 Linux swap / So c1 DRDOS/sec (FAT- 2 XENIX root 39 Plan 9 83 Linux c4 DRDOS/sec (FAT- 3 XENIX usr 3c PartitionMagic 84 OS/2 hidden C: c6 DRDOS/sec (FAT- 4 FAT16 <32M 40 Venix 80286 85 Linux extended c7 Syrinx 5 Extended 41 PPC PReP Boot 86 NTFS volume set da Non-FS data 6 FAT16 42 SFS 87 NTFS volume set db CP/M / CTOS / . 7 HPFS/NTFS/exFAT 4d QNX4.x 88 Linux plaintext de Dell Utility 8 AIX 4e QNX4.x 2nd part 8e Linux LVM df BootIt 9 AIX bootable 4f QNX4.x 3rd part 93 Amoeba e1 DOS access a OS/2 Boot Manag 50 OnTrack DM 94 Amoeba BBT e3 DOS R/O b W95 FAT32 51 OnTrack DM6 Aux 9f BSD/OS e4 SpeedStor c W95 FAT32 (LBA) 52 CP/M a0 IBM Thinkpad hi eb BeOS fs e W95 FAT16 (LBA) 53 OnTrack DM6 Aux a5 FreeBSD ee GPT f W95 Ext'd (LBA) 54 OnTrackDM6 a6 OpenBSD ef EFI (FAT-12/16/10 OPUS 55 EZ-Drive a7 NeXTSTEP f0 Linux/PA-RISC b11 Hidden FAT12 56 Golden Bow a8 Darwin UFS f1 SpeedStor 12 Compaq diagnost 5c Priam Edisk a9 NetBSD f4 SpeedStor 14 Hidden FAT16 <3 61 SpeedStor ab Darwin boot f2 DOS secondary 16 Hidden FAT16 63 GNU HURD or Sys af HFS / HFS+ fb VMware VMFS 17 Hidden HPFS/NTF 64 Novell Netware b7 BSDI fs fc VMware VMKCORE 18 AST SmartSleep 65 Novell Netware b8 BSDI swap fd Linux raid auto1b Hidden W95 FAT3 70 DiskSecure Mult bb Boot Wizard hid fe LANstep 1c Hidden W95 FAT3 75 PC/IX be Solaris boot ff BBT 1e Hidden W95 FAT1 80 Old Minix Hex code (type L to list all codes): 82 Changed type of partition 'Linux' to 'Linux swap / Solaris'Command (m for help): mCommand action a toggle a bootable flag b edit bsd disklabel c toggle the dos compatibility flag d delete a partition g create a new empty GPT partition table G create an IRIX (SGI) partition table l list known partition types m print this menu n add a new partition o create a new empty DOS partition table p print the partition table q quit without saving changes s create a new empty Sun disklabel t change a partition's system id u change display/entry units v verify the partition table w write table to disk and exit x extra functionality (experts only)Command (m for help): pDisk /dev/sdc: 2147 MB, 2147483648 bytes, 4194304 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk label type: dosDisk identifier: 0x3990990c Device Boot Start End Blocks Id System/dev/sdc1 2048 206847 102400 82 Linux swap / SolarisCommand (m for help): wThe partition table has been altered!Calling ioctl() to re-read partition table.Syncing disks.[root@rhel7 ~]# fdisk -lDisk /dev/sda: 21.5 GB, 21474836480 bytes, 41943040 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk label type: dosDisk identifier: 0x0006c7ae Device Boot Start End Blocks Id System/dev/sda1 * 2048 1026047 512000 83 Linux/dev/sda2 1026048 41943039 20458496 8e Linux LVMDisk /dev/sdb: 5368 MB, 5368709120 bytes, 10485760 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk label type: dosDisk identifier: 0x0c16d904 Device Boot Start End Blocks Id System/dev/sdb1 2048 10485759 5241856 83 LinuxDisk /dev/sdc: 2147 MB, 2147483648 bytes, 4194304 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk label type: dosDisk identifier: 0x3990990c Device Boot Start End Blocks Id System/dev/sdc1 2048 206847 102400 82 Linux swap / SolarisDisk /dev/mapper/rhel-root: 18.8 GB, 18756927488 bytes, 36634624 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk /dev/mapper/rhel-swap: 2147 MB, 2147483648 bytes, 4194304 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytes[root@rhel7 ~]# mkswap /dev/sdc1 --格式化/dev/sdc1为swap分区Setting up swapspace version 1, size = 102396 KiBno label, UUID=b74fbc00-3f2e-4dea-99da-a17de3f798c3 [root@rhel7 ~]# swapon /dev/sdc1 --激活swap分区
[root@rhel7 ~]# free -m --可以看到swap增加了100M total used free shared buff/cache available Mem: 1840 91 1603 8 144 1605 Swap: 2147 0 2147 [root@rhel7 ~]#