linux磁盘与文件系统管理
管理分区
列出所有块设备
[root@centos7 ~]#lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 200G 0 disk
├─sda1 8:1 0 1G 0 part /boot
├─sda2 8:2 0 50G 0 part /
├─sda3 8:3 0 4G 0 part [SWAP]
├─sda4 8:4 0 1K 0 part
└─sda5 8:5 0 30G 0 part /data
sr0 11:0 1 8.8G 0 rom /run/media/root/CentOS 7 x86_64
创建分区使用：
• fdisk 创建MBR分区
• gdisk 创建GPT分区
• parted 高级分区操作
重新设置内存中的内核分区表版本
• partprobe
生成uuid 128bit的二进制组成十六进制的uuid
[root@centos7 ~]#uuidgen
44e3e725-610d-4730-8515-3cad2c55d3d3
parted命令
! parted的操作都是实时生效的，小心使用 !
用法：parted [选项]... [设备 [命令 [参数]...]...]
parted /dev/sdb mklabel gpt|msdos
parted /dev/sdb print
parted /dev/sdb mkpart primary 1 200 （默认M）
parted /dev/sdb rm 1
parted –l 列出分区信息
清空分区表
[root@centos7 ~]#dd if=/dev/zero of=/dev/sdb bs=1 count=512
512+0 records in
512+0 records out
512 bytes (512 B) copied, 0.00343371 s, 149 kB/s
进行磁盘分区
[root@centos7 ~]#fdisk /dev/sdb <== 对sdb进行分区
Welcome 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 table
Building a new DOS disklabel with disk identifier 0x512ef772.
Command (m for help): m <== 查看帮助列表
Command 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): p <== 列出这个磁盘的分区形况
Disk /dev/sdb: 21.5 GB, 21474836480 bytes, 41943040 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x512ef772
Device Boot Start End Blocks Id System
Command (m for help): n <== 选择分区
Partition type:
p primary (0 primary, 0 extended, 4 free)
e extended
Select (default p): p
Partition number (1-4, default 1):
First sector (2048-41943039, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-41943039, default 41943039): +1G <== 分1G
Partition 1 of type Linux and of size 1 GiB is set
Command (m for help): n
Partition type:
p primary (2 primary, 0 extended, 2 free)
e extended
Select (default p): e <== e为扩展分区
Partition number (3,4, default 3): 3
First sector (6293504-41943039, default 6293504):
Using default value 6293504
Last sector, +sectors or +size{K,M,G} (6293504-41943039, default 41943039): +10G
Partition 3 of type Extended and of size 10 GiB is set
Command (m for help): p
Disk /dev/sdb: 21.5 GB, 21474836480 bytes, 41943040 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x512ef772
Device Boot Start End Blocks Id System
/dev/sdb1 2048 2099199 1048576 83 Linux
/dev/sdb2 2099200 6293503 2097152 83 Linux
/dev/sdb3 6293504 27265023 10485760 5 Extended <== 扩展分区的id 5
Command (m for help): p
Disk /dev/sdb: 21.5 GB, 21474836480 bytes, 41943040 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x512ef772
Device Boot Start End Blocks Id System
/dev/sdb1 2048 2099199 1048576 83 Linux
Command (m for help): n <== 继续分
Partition type:
p primary (2 primary, 1 extended, 1 free)
l logical (numbered from 5)
Select (default p): l <== 选择l 再扩展分区里分区
Adding logical partition 5
First sector (6295552-27265023, default 6295552):
Using default value 6295552
Last sector, +sectors or +size{K,M,G} (6295552-27265023, default 27265023): +1G
Partition 5 of type Linux and of size 1 GiB is set
Command (m for help): w <== 退出存盘
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
查看硬盘分区的方法
[root@centos7 ~]#lsblk <== 查看内存中的分区
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 200G 0 disk
├─sda1 8:1 0 1G 0 part /boot
├─sda2 8:2 0 50G 0 part /
├─sda3 8:3 0 4G 0 part [SWAP]
├─sda4 8:4 0 1K 0 part
└─sda5 8:5 0 30G 0 part /data
sdb 8:16 0 20G 0 disk
├─sdb1 8:17 0 1G 0 part
├─sdb2 8:18 0 2G 0 part
├─sdb3 8:19 0 1K 0 part
├─sdb5 8:21 0 1G 0 part
├─sdb6 8:22 0 2G 0 part
└─sdb7 8:23 0 2G 0 part
sr0 11:0 1 8.8G 0 rom /run/media/root/CentOS 7 x86_64
[root@centos7 ~]#ls /dev/sdb* <== 查看内存中的分区
/dev/sdb /dev/sdb1 /dev/sdb2 /dev/sdb3 /dev/sdb5 /dev/sdb6 /dev/sdb7
[root@centos7 ~]#cat /proc/partitions <== 查看内存中的分区
major minor #blocks name
8 16 20971520 sdb
8 17 1048576 sdb1
8 18 2097152 sdb2
8 19 1 sdb3
8 21 1048576 sdb5
8 22 2097152 sdb6
8 23 2097152 sdb7
8 0 209715200 sda
8 1 1048576 sda1
8 2 52428800 sda2
8 3 4194304 sda3
8 4 1 sda4
8 5 31457280 sda5
11 0 9177088 sr0
[root@centos7 ~]#fdisk -l /dev/sdb <== 只有这个才能看到硬盘中的分区数据详情
Disk /dev/sdb: 21.5 GB, 21474836480 bytes, 41943040 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x512ef772
Device Boot Start End Blocks Id System
/dev/sdb1 2048 2099199 1048576 83 Linux
/dev/sdb2 2099200 6293503 2097152 83 Linux
/dev/sdb3 6293504 27265023 10485760 5 Extended
/dev/sdb5 6295552 8392703 1048576 83 Linux
/dev/sdb6 8394752 12589055 2097152 83 Linux
/dev/sdb7 12591104 16785407 2097152 83 Linux
查看开机时间
[root@centos7 ~]#uptime <== 查看开机时间
19:50:04 up 2:19, 2 users, load average: 0.00, 0.01, 0.05
同步分区到内存中 生效
[root@centos7 ~]#partprobe /dev/sdb <== cenos5 ，7 可以用这个 6不行
[root@centos7 ~]#partx -a /dev/sdb <== 这是centos6专用的 -a是增加分区是用的
[root@centos7 ~]#partx -d --nr 6 /dev/sdb <== -d是同步删除分区 6=是sdb6 在跟上设备名
gdisk 分区 擅长管理gtp分区
gdisk /dev/sdb 类fdisk 的GPT分区工具
fdisk -l [-u] [device…] 查看分区
fdisk /dev/sdb 管理分区
子命令：
p 分区列表
t 更改分区类型
n 创建新分区
d 删除分区
v 校验分区
u 转换单位
w 保存并退出
q 不保存并退出
硬盘分好区后不能使用 要格式化
创建文件系统
[root@centos7 ~]#lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 200G 0 disk
├─sda1 8:1 0 1G 0 part /boot
├─sda2 8:2 0 50G 0 part /
├─sda3 8:3 0 4G 0 part [SWAP]
├─sda4 8:4 0 1K 0 part <== 扩展分区不能创建文件系统
└─sda5 8:5 0 30G 0 part /data
sdb 8:16 0 20G 0 disk
├─sdb1 8:17 0 1G 0 part
├─sdb2 8:18 0 2G 0 part
├─sdb3 8:19 0 1K 0 part <== 扩展分区不能创建文件系统
├─sdb5 8:21 0 1G 0 part
├─sdb6 8:22 0 2G 0 part
└─sdb7 8:23 0 2G 0 part
[root@centos7 ~]#ls /lib/modules/3.10.0-862.el7.x86_64/kernel/fs <== 查看系统支持的文件系统
binfmt_misc.ko.xz ceph dlm fat gfs2 lockd nfs_common overlayfs udf
btrfs cifs exofs fscache isofs mbcache.ko.xz nfsd pstore xfs
cachefiles cramfs ext4 fuse jbd2 nfs nls squashfs
[root@centos7 ~]#df -T <== 查看一挂在磁盘的文件系统
Filesystem Type 1K-blocks Used Available Use% Mounted on
/dev/sda2 xfs 52403200 5018204 47384996 10% /
devtmpfs devtmpfs 999156 0 999156 0% /dev
tmpfs tmpfs 1015084 0 1015084 0% /dev/shm
tmpfs tmpfs 1015084 10184 1004900 2% /run
tmpfs tmpfs 1015084 0 1015084 0% /sys/fs/cgroup
/dev/sda5 xfs 31441920 33024 31408896 1% /data
/dev/sda1 xfs 1038336 158040 880296 16% /boot
tmpfs tmpfs 203020 8 203012 1% /run/user/0
/dev/sr0 iso9660 9176232 9176232 0 100% /run/media/root/CentOS 7 x86_64
格式化文件系统
[root@centos7 ~]#mke2fs /dev/sdb1 mke2fs e2是ext2文件系统格式
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
65536 inodes, 262144 blocks
13107 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=268435456
8 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376
Allocating group tables: done
Writing inode tables: done
Writing superblocks and filesystem accounting information: done
[root@centos7 ~]#blkid /dev/sdb1 <== 查看sdb1的文件系统格式
/dev/sdb1: UUID="3f84c9bf-60d4-47aa-8a0c-33afb688e845" TYPE="ext2"
[root@centos7 ~]#tune2fs -l /dev/sdb1 <=== 查看
tune2fs 1.42.9 (28-Dec-2013)
Filesystem volume name: <none>
Last mounted on: <not available>
Filesystem UUID: 3f84c9bf-60d4-47aa-8a0c-33afb688e845
Filesystem magic number: 0xEF53
Filesystem revision #: 1 (dynamic)
Filesystem features: ext_attr resize_inode dir_index filetype sparse_super large_file <==没有日志功能
Filesystem flags: signed_directory_hash
Default mount options: user_xattr acl <== 挂载选项 默认挂载属性
Filesystem state: clean <== 文件系统的状态
Errors behavior: Continue
Filesystem OS type: Linux
Inode count: 65536 <== 节点的数量
Block count: 262144 <== 块的数量
Reserved block count: 13107 <== 保留的块数量
Free blocks: 257701
Free inodes: 65525 <== 空闲的节点数
First block: 0
Block size: 4096 <== 指块大小 分配给一个单位的块 1k个文件也占用一个块
Fragment size: 4096
Reserved GDT blocks: 63
Blocks per group: 32768 <== 一个组多少块
Fragments per group: 32768 同上
Inodes per group: 8192
Inode blocks per group: 512
Filesystem created: Sun Oct 21 13:31:21 2018
Last mount time: n/a
Last write time: Sun Oct 21 13:31:21 2018
Mount count: 0 <== 挂在的次数
Maximum mount count: -1 <== 最多挂载次数
Last checked: Sun Oct 21 13:31:21 2018
Check interval: 0 (<none>) <== 检查间隔
Reserved blocks uid: 0 (user root) <==保留的使用者
Reserved blocks gid: 0 (group root) <==保留的使用者
First inode: 11
Inode size: 256 <== 一个源数据在磁盘上占用256个字节
Required extra isize: 28
Desired extra isize: 28
Default directory hash: half_md4
Directory Hash Seed: d645257d-548e-40e9-93fd-5059641733f6
下面格式化并指定块大小
[root@centos7 ~]#mkfs.ext4 -b 1024 /dev/sdb1 <== 一块1024 选项-b
[root@centos7 ~]#mkfs.ext4 -b 1024 -m 0.1 /dev/sdb1 <== -m0.1 保留的块大小 %0.1 给管理员用的
[root@centos7 ~]#mkfs.ext4 -b 1024 -m 0.1 -L "/mut/sdb1" /dev/sdb1 <== -L卷标名字
[root@centos7 ~]#blkid /dev/sdb1 <== 双引号里的卷标信息
/dev/sdb1: LABEL="/mut/sdb1" UUID="c0c719af-cc3d-407b-be98-3257b45f1e47" TYPE="ext4"
[root@centos7 ~]#blkid -U 8a474365-580f-4413-8f9e-a3cb4a220938 <== -U查询uid设别名
/dev/sda1
[root@centos7 ~]#e2label /dev/sdb1 /mnt/sdb1 <== 设置卷标 设备名在前 名在后 名是挂载路径
[root@centos7 ~]#blkid -L /mnt/sdb1 <== 查询卷标名对应的名
/dev/sdb1
[root@centos7 ~]#sed -rn 's#^UUID=(.*) / .*#\1#p' /etc/fstab <== sed查询uuid设备名
e3fccf98-adeb-4428-8b7b-0f761cd30a60
[root@centos7 ~]#blkid -U `sed -rn 's#^UUID=(.*) / .*#\1#p' /etc/fstab `
/dev/sda2
[root@centos6 ~]#e2label /dev/sda1 <== 查看卷标信息 /boot： 卷标名
/boot
[root@centos6 ~]#blkid /dev/sda1
/dev/sda1: LABEL="/boot" UUID="739573ac-9e94-424d-abe0-d253b8dcecdd" TYPE="ext4"
findfs:查找分区
findfs [options] LABEL=
findfs [opyions] UUID=
tune2fs
tune2fs：重新设定ext系列文件系统可调整参数的值
-l 查看指定文件系统超级块信息；super block
-L 'LABEL‘ 修改卷标
-m # 修预留给管理员的空间百分比
-j 将ext2升级为ext3
-O 文件系统属性启用或禁用, –O ^has_journal
-o 调整文件系统的默认挂载选项，–o ^acl
-U UUID 修改UUID号
dumpe2fs：
块分组管理，32768块
-h：查看超级块信息，不显示分组信息
[root@centos7 ~]#mount /dev/sdb1 /mnt/sdb1/ <== 挂载sdb1到mnt sdb1下
[root@centos7 ~]#cd /mnt/sdb1/
[root@centos7 sdb1]#ls
lost+found <== 挂载成功后就有这个目录文件
[root@centos7 sdb1]# touch f1 这就挂在完了 可以使用
[root@centos7 sdb1]#ls
f1 lost+found
mount -u uuid挂载方式：
[root@centos7 ~]#mount -U 92e727b4-9535-4672-b1b9-f86ea688669c /mnt/sdb1/ blkid查看uuid
[root@centos7 ~]#df -h 就可以查看到挂在的设备了
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 50G 4.8G 46G 10% /
devtmpfs 976M 0 976M 0% /dev
tmpfs 992M 0 992M 0% /dev/shm
tmpfs 992M 11M 981M 2% /run
tmpfs 992M 0 992M 0% /sys/fs/cgroup
/dev/sda5 30G 33M 30G 1% /data
/dev/sda1 1014M 155M 860M 16% /boot
tmpfs 199M 36K 199M 1% /run/user/0
/dev/sr0 8.8G 8.8G 0 100% /run/media/root/CentOS 7 x86_64
/dev/sdb1 976M 2.6M 907M 1% /mnt/sdb1
查看谁在使用这个磁盘设备：
[root@centos7 ~]#lsof /mnt/sdb1 <== 谁在使用
[root@centos7 ~]#fuser -v /mnt/sdb1 <== 谁在使用
USER PID ACCESS COMMAND
/mnt/sdb1: root kernel mount /mnt/sdb1 <== root在使用
用mount命令挂载文件系统
挂载方法：mount DEVICE MOUNT_POINT
mount：通过查看/etc/mtab文件显示当前已挂载的所有设备
mount [-fnrsvw] [-t vfstype] [-o options] device dir
device：指明要挂载的设备；
(1) 设备文件：例如/dev/sda5
(2) 卷标：-L ‘LABEL’, 例如 -L ‘MYDATA’
(3) UUID, -U ‘UUID’：例如 -U ‘0c50523c-43f1-45e7-
85c0-a126711d406e’
(4) 伪文件系统名称：proc, sysfs, devtmpfs, configfs
dir：挂载点
事先存在；建议使用空目录
进程正在使用中的设备无法被卸载
mount常用命令选项
-t vsftype 指定要挂载的设备上的文件系统类型
-r readonly， 只读挂载
-w read and write, 读写挂载
-n 不更新/etc/mtab，mount不可见
-a 自动挂载所有支持自动挂载的设备(定义在了/etc/fstab文件中，且挂载选项中有auto功能)
-L ‘LABEL’ 以卷标指定挂载设备
-U ‘UUID’ 以UUID指定要挂载的设备
-B, --bind 绑定目录到另一个目录上
查看内核追踪到的已挂载的所有设备
cat /proc/mounts
mount常用命令选项
-o options： (挂载文件系统的选项)，多个选项使用逗号分隔
async 异步模式 sync 同步模式,内存更改时，同时写磁盘
atime/noatime 包含目录和文件
diratime/nodiratime 目录的访问时间戳
auto/noauto 是否支持自动挂载,是否支持-a选项
exec/noexec 是否支持将文件系统上运行应用程序
dev/nodev 是否支持在此文件系统上使用设备文件
suid/nosuid 是否支持suid和sgid权限
remount 重新挂载
ro只读 rw读写
user/nouser 是否允许普通用户挂载此设备，/etc/fstab使用
acl 启用此文件系统上的acl功能
loop 使用loop设备
判断这个文件加 是不是个挂载点
[root@centos7 ~]#findmnt /data 判断data
TARGET SOURCE FSTYPE OPTIONS
/data /dev/sda5 xfs rw,relatime,attr2,inode64,noquota <== 确定是个挂载点
[root@centos7 ~]#findmnt /etc <== 判断etc是不是挂载点
[root@centos7 ~]#echo $? <== 0 不是
1 <== 1代表不是挂载点
查看swap的类型 82 :
[root@centos7 ~]#fdisk -l /dev/sda
Disk /dev/sda: 214.7 GB, 214748364800 bytes, 419430400 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x000a6848
Device Boot Start End Blocks Id System
/dev/sda1 * 2048 2099199 1048576 83 Linux
/dev/sda2 2099200 106956799 52428800 83 Linux
/dev/sda3 106956800 115345407 4194304 82 Linux swap / Solaris
/dev/sda4 115345408 419430399 152042496 5 Extended
/dev/sda5 115347456 178262015 31457280 83 Linux
增加swap
创建一个新的磁盘 sdc
[root@centos7 ~]#fdisk /dev/sdc <== 分区
Welcome 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 table
Building a new DOS disklabel with disk identifier 0x1f8a9087.
Command (m for help): n
Partition type:
p primary (0 primary, 0 extended, 4 free)
e extended
Select (default p): p <== 主分区
Partition number (1-4, default 1):
First sector (2048-41943039, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-41943039, default 41943039): +4G <==4g大小
Partition 1 of type Linux and of size 4 GiB is set
Command (m for help): p
Disk /dev/sdc: 21.5 GB, 21474836480 bytes, 41943040 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x1f8a9087
Device Boot Start End Blocks Id System
/dev/sdc1 2048 8390655 4194304 83 Linux
Command (m for help): t <== 指定 swap id号 82
Selected partition 1
Hex code (type L to list all codes): l <== l列出所有id号
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 b
11 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 auto
1b 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 <== 设置82
Changed type of partition 'Linux' to 'Linux swap / Solaris'
Command (m for help): p
Disk /dev/sdc: 21.5 GB, 21474836480 bytes, 41943040 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x1f8a9087
Device Boot Start End Blocks Id System
/dev/sdc1 2048 8390655 4194304 82 Linux swap / Solaris
Command (m for help): w <== 存盘退出
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
[root@centos7 ~]#lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 200G 0 disk
├─sda1 8:1 0 1G 0 part /boot
├─sda2 8:2 0 50G 0 part /
├─sda3 8:3 0 4G 0 part [SWAP]
├─sda4 8:4 0 1K 0 part
└─sda5 8:5 0 30G 0 part /data
sdb 8:16 0 20G 0 disk
├─sdb1 8:17 0 1G 0 part /mnt/sdb1
├─sdb2 8:18 0 2G 0 part
├─sdb3 8:19 0 1K 0 part
├─sdb5 8:21 0 1G 0 part
├─sdb6 8:22 0 2G 0 part
└─sdb7 8:23 0 2G 0 part
sdc 8:32 0 20G 0 disk
└─sdc1 8:33 0 4G 0 part
sr0 11:0 1 8.8G 0 rom /run/media/root/CentOS 7 x86_64
[root@centos7 ~]#df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/sda2 52403200 5015224 47387976 10% /
devtmpfs 999156 0 999156 0% /dev
tmpfs 1015084 0 1015084 0% /dev/shm
tmpfs 1015084 10684 1004400 2% /run
tmpfs 1015084 0 1015084 0% /sys/fs/cgroup
/dev/sda5 31441920 33024 31408896 1% /data
/dev/sdb1 999320 2564 927944 1% /mnt/sdb1
/dev/sda1 1038336 158040 880296 16% /boot
tmpfs 203020 28 202992 1% /run/user/0
/dev/sr0 9176232 9176232 0 100% /run/media/root/CentOS 7 x86_64
[root@centos7 ~]#mkswap /dev/sdc1 <== 建立swap分区
Setting up swapspace version 1, size = 4194300 KiB
no label, UUID=d823147f-4fed-4b96-8970-97d8d2580f5c
[root@centos7 ~]#blkid
/dev/sda1: UUID="8a474365-580f-4413-8f9e-a3cb4a220938" TYPE="xfs"
/dev/sda2: UUID="e3fccf98-adeb-4428-8b7b-0f761cd30a60" TYPE="xfs"
/dev/sda3: UUID="1018f445-9c4c-43db-88cb-ae04ee7b4f63" TYPE="swap"
/dev/sda5: UUID="72a23ce1-e9c0-4669-8829-f8313f90b176" TYPE="xfs"
/dev/sdb1: LABEL="/mnt/sdb1" UUID="92e727b4-9535-4672-b1b9-f86ea688669c" TYPE="ext4"
/dev/sdb2: UUID="03e3a7a9-a331-4899-a03b-95c6ff729617" TYPE="xfs"
/dev/sr0: UUID="2018-05-07-12-53-47-00" LABEL="CentOS 7 x86_64" TYPE="iso9660" PTTYPE="dos"
/dev/sdc1: UUID="d823147f-4fed-4b96-8970-97d8d2580f5c" TYPE="swap"
[root@centos7 ~]#vim /etc/fstab <== 打开配置文件 添加进去生效
[root@centos7 ~]#free -h <== 原有swap大小 和内存使用情况
total used free shared buff/cache available
Mem: 1.9G 715M 769M 10M 497M 1.0G
Swap: 4.0G 0B 4.0G
[root@centos7 ~]#swapon -a <== 同步新的4g swap
[root@centos7 ~]#free -h <== 生效了 一共8g
total used free shared buff/cache available
Mem: 1.9G 718M 766M 10M 497M 1.0G
Swap: 8.0G 0B 8.0G
swap 优先级提高
[root@centos7 ~]#vim /etc/fstab <==打开挂载配置文件
UUID=d823147f-4fed-4b96-8970-97d8d2580f5c swap swap pri=10 <== 添加此项 > 0 0
[root@centos7 ~]#free -h
total used free shared buff/cache available
Mem: 1.9G 715M 769M 10M 497M 1.0G
Swap: 4.0G 0B 4.0G
[root@centos7 ~]#swapon -a
[root@centos7 ~]#free -h
total used free shared buff/cache available
Mem: 1.9G 718M 766M 10M 497M 1.0G
Swap: 8.0G 0B 8.0G
[root@centos7 ~]#vim /etc/fstab
[root@centos7 ~]#cat /proc/swaps
Filename Type Size Used Priority
/dev/sda3 partition 4194300 0 -1
/dev/sdc1 partition 4194300 0 -2
[root@centos7 ~]#swapoff /dev/sdc1 <==先禁用他
[root@centos7 ~]#cat /proc/swaps
Filename Type Size Used Priority
/dev/sda3 partition 4194300 0 -1
[root@centos7 ~]#swapon -a 再启用他
[root@centos7 ~]#cat /proc/swaps <== 就ok了
Filename Type Size Used Priority
/dev/sda3 partition 4194300 0 -1
/dev/sdc1 partition 4194300 0 10