磁盘

2020-02-07 本文已影响0人 mrwangjian

fdisk

p print显示磁盘分区信息

n new 创建磁盘分区

d delete 删除

w 保存并退出

创建1个使用 /dev/sdb 所有容量的分区挂载到 /data 目录

第1个里程碑-磁盘分区

[root@oldboyedu60-lnb ~]# fdisk /dev/sdb

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 0x162015cc.

Command (m for help): p

Disk /dev/sdb: 213 MB, 213909504 bytes, 417792 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: 0x162015cc

Device Boot Start End Blocks Id System

Command (m for help): n

Partition type:

p primary (0 primary, 0 extended, 4 free)

e extended

Select (default p):

Using default response p

Partition number (1-4, default 1):

First sector (2048-417791, default 2048):

Using default value 2048

Last sector, +sectors or +size{K,M,G} (2048-417791, default 417791):

Using default value 417791

Partition 1 of type Linux and of size 203 MiB is set

Command (m for help): p

Disk /dev/sdb: 213 MB, 213909504 bytes, 417792 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: 0x162015cc

Device Boot Start End Blocks Id System

/dev/sdb1 2048 417791 207872 83 Linux

Command (m for help): w

The partition table has been altered!

Calling ioctl() to re-read partition table.

Syncing disks.

第2个里程碑-磁盘分区

mkfs.xfs /dev/sdb1

第3个里程碑-磁盘挂载

[root@oldboyedu60-lnb ~]# mkdir -p /data

[root@oldboyedu60-lnb ~]# mount /dev/sdb1 /data

[root@oldboyedu60-lnb ~]# df -h

Filesystem Size Used Avail Use% Mounted on

/dev/sda3 99G 1.6G 98G 2% /

devtmpfs 981M 0 981M 0% /dev

tmpfs 992M 0 992M 0% /dev/shm

tmpfs 992M 9.6M 982M 1% /run

tmpfs 992M 0 992M 0% /sys/fs/cgroup

/dev/sda1 197M 102M 95M 52% /boot

tmpfs 199M 0 199M 0% /run/user/0

/dev/sdb1 200M 11M 190M 6% /data

[root@oldboyedu60-lnb ~]# blkid

/dev/sda1: UUID="67c85f99-9ff1-45cd-8aff-3bf1d5610651" TYPE="xfs"

/dev/sda2: UUID="ad818355-5849-4606-ad6e-a84bec3fe0e1" TYPE="swap"

/dev/sda3: UUID="1ca5b5e0-449a-4a91-915a-9d3d0c26f470" TYPE="xfs"

/dev/sdb1: UUID="73a994ec-49ad-4e98-868c-e1a9f8d07130" TYPE="xfs"

/dev/sr0: UUID="2018-05-03-20-55-23-00" LABEL="CentOS 7 x86_64" TYPE="iso9660" PTTYPE="dos"

[root@oldboyedu60-lnb ~]# tail -1 /etc/fstab

/dev/sdb1 /data xfs defaults 0 0

[root@oldboyedu60-lnb ~]# umount /data

[root@oldboyedu60-lnb ~]# df -h

Filesystem Size Used Avail Use% Mounted on

/dev/sda3 99G 1.6G 98G 2% /

devtmpfs 981M 0 981M 0% /dev

tmpfs 992M 0 992M 0% /dev/shm

tmpfs 992M 9.6M 982M 1% /run

tmpfs 992M 0 992M 0% /sys/fs/cgroup

/dev/sda1 197M 102M 95M 52% /boot

tmpfs 199M 0 199M 0% /run/user/0

[root@oldboyedu60-lnb ~]# mount

[root@oldboyedu60-lnb ~]# mount -a

#根据/etc/fstab 内容挂载所有

[root@oldboyedu60-lnb ~]# df -h

Filesystem Size Used Avail Use% Mounted on

/dev/sda3 99G 1.6G 98G 2% /

devtmpfs 981M 0 981M 0% /dev

tmpfs 992M 0 992M 0% /dev/shm

tmpfs 992M 9.6M 982M 1% /run

tmpfs 992M 0 992M 0% /sys/fs/cgroup

/dev/sda1 197M 102M 95M 52% /boot

tmpfs 199M 0 199M 0% /run/user/0

/dev/sdb1 200M 11M 190M 6% /data

[故障集合]Linux必备故障及原因50个

https://www.jianshu.com/p/99ec5bb4183f

fdisk 磁盘分区

-l 查看磁盘分区信息

mkfs make filesystem 创建文件系统（格式化 format）

mkfs -t xfs === mkfs.xfs

xfs CentOS 7默认的文件系统

ext4 CentOS 6默认

mkfs.ext4

mkfs.xfs

mount 挂载

-a 根据/etc/fstab内容挂载所有

umount 卸载

df 查询磁盘使用情况

-h

JAVA 大量占用内存内存不足 swap

如何增加swap

查看swap

free -h

free -m

第1个里程碑-创建指定大小的文件

500MB文件

/dev/null 黑洞

/dev/zero 输出

dd if=/dev/zero of=/tmp/500M bs=1M count=500

input file output file block size 次数

输入文件输出文件每次复制多少

[root@oldboyedu60-lnb ~]# file /tmp/500m

/tmp/500m: data

第2个里程碑-成为swap （格式化）

mkfs

mkswap

第3个里程碑-生效（挂载）

swapon /tmp/500m

swapoff /tmp/500m

[root@oldboyedu60-lnb ~]# swapon /tmp/500m

swapon: /tmp/500m: insecure permissions 0644, 0600 suggested.

[root@oldboyedu60-lnb ~]# free -h

total used free shared buff/cache available

Mem: 1.9G 95M 1.2G 9.6M 644M 1.7G

Swap: 1.5G 0B 1.5G

[root@oldboyedu60-lnb ~]# swapon -s

Filename Type Size Used Priority

/dev/sda2 partition 1048572 0 -1

/tmp/500m file 511996 0 -2

[root@oldboyedu60-lnb ~]# tail -2 /etc/fstab

/dev/sdb1 /data xfs defaults 0 0

/tmp/500m swap swap defaults 0 0

特殊文件系统

tmpfs 把数据写入到这个文件系统中就相当于写入到了内存

[root@oldboyedu60-lnb ~]# mkdir /mem

[root@oldboyedu60-lnb ~]# mount -t tmpfs -o size=500m tmpfs /mem

[root@oldboyedu60-lnb ~]# df -h

Filesystem Size Used Avail Use% Mounted on

/dev/sda3 99G 2.7G 97G 3% /

devtmpfs 981M 0 981M 0% /dev

tmpfs 992M 0 992M 0% /dev/shm

tmpfs 992M 9.6M 982M 1% /run

tmpfs 992M 0 992M 0% /sys/fs/cgroup

/dev/sda1 197M 102M 95M 52% /boot

tmpfs 199M 0 199M 0% /run/user/0

/dev/sdb1 200M 11M 190M 6% /data

tmpfs 500M 0 500M 0% /mem

[root@oldboyedu60-lnb ~]#

[root@oldboyedu60-lnb ~]# tail -3 /etc/fstab

/dev/sdb1 /data xfs defaults 0 0

/tmp/500m swap swap defaults 0 0

tmpfs /mem tmpfs size=500m 0 0

du -sh /* |sort -h

文件删除原理：

1.硬链接数（入口）

2.没有进程调用（没人使用）

lsof list open files 显示系统中所有被打开的文件（正在使用中）

第1列命令文件大小(字节) inode号码被使用中的文件

[root@oldboyedu60-lnb ~]# lsof |grep hosts

tail 2499 root 3r REG 8,3 193 67138812 /etc/hosts

[root@oldboyedu60-lnb ~]# lsof |grep hosts

vim 2541 root 4u REG 8,3 4096 67138811 /etc/.hosts.swp

模拟 inode满了磁盘空间不足

[root@oldboyedu60-lnb ~]# dd if=/dev/zero of=/tmp/sdf bs=1k count=100

100+0 records in

100+0 records out

102400 bytes (102 kB) copied, 0.000595446 s, 172 MB/s

[root@oldboyedu60-lnb ~]# mkfs.ext4 /tmp/sdf

mke2fs 1.42.9 (28-Dec-2013)

/tmp/sdf is not a block special device.

Proceed anyway? (y,n) y

[root@oldboyedu60-lnb ~]# mount /tmp/sdf /mnt/

[root@oldboyedu60-lnb ~]# df -h

Filesystem Size Used Avail Use% Mounted on

/dev/sda3 99G 7.3G 92G 8% /

devtmpfs 981M 0 981M 0% /dev

tmpfs 992M 0 992M 0% /dev/shm

tmpfs 992M 9.6M 982M 1% /run

tmpfs 992M 0 992M 0% /sys/fs/cgroup

/dev/sda1 197M 102M 95M 52% /boot

tmpfs 199M 0 199M 0% /run/user/0

/dev/sdb1 200M 11M 190M 6% /data

tmpfs 500M 500M 0 100% /mem

/dev/loop0 93K 14K 72K 17% /mnt

[root@oldboyedu60-lnb ~]#

[root@oldboyedu60-lnb ~]# df -i

Filesystem Inodes IUsed IFree IUse% Mounted on

/dev/sda3 51801600 60003 51741597 1% /

devtmpfs 251024 419 250605 1% /dev

tmpfs 253771 1 253770 1% /dev/shm

tmpfs 253771 747 253024 1% /run

tmpfs 253771 16 253755 1% /sys/fs/cgroup

/dev/sda1 102400 326 102074 1% /boot

tmpfs 253771 1 253770 1% /run/user/0

/dev/sdb1 103936 3 103933 1% /data

tmpfs 253771 2 253769 1% /mem

/dev/loop0 16 11 5 69% /mnt

[root@oldboyedu60-lnb ~]# df -h

Filesystem Size Used Avail Use% Mounted on

/dev/sda3 99G 7.3G 92G 8% /

devtmpfs 981M 0 981M 0% /dev

tmpfs 992M 0 992M 0% /dev/shm

tmpfs 992M 9.6M 982M 1% /run

tmpfs 992M 0 992M 0% /sys/fs/cgroup

/dev/sda1 197M 102M 95M 52% /boot

tmpfs 199M 0 199M 0% /run/user/0

/dev/sdb1 200M 11M 190M 6% /data

tmpfs 500M 500M 0 100% /mem

/dev/loop0 93K 14K 72K 17% /mnt

[root@oldboyedu60-lnb ~]# touch /mnt/{1..6}.txt

touch: cannot touch ‘/mnt/6.txt’: No space left on device

[root@oldboyedu60-lnb ~]# df -h

Filesystem Size Used Avail Use% Mounted on

/dev/sda3 99G 7.3G 92G 8% /

devtmpfs 981M 0 981M 0% /dev

tmpfs 992M 0 992M 0% /dev/shm

tmpfs 992M 9.6M 982M 1% /run

tmpfs 992M 0 992M 0% /sys/fs/cgroup

/dev/sda1 197M 102M 95M 52% /boot

tmpfs 199M 0 199M 0% /run/user/0

/dev/sdb1 200M 11M 190M 6% /data

tmpfs 500M 500M 0 100% /mem

/dev/loop0 93K 14K 72K 17% /mnt

[root@oldboyedu60-lnb ~]#

[root@oldboyedu60-lnb ~]# df -i

Filesystem Inodes IUsed IFree IUse% Mounted on

/dev/sda3 51801600 60003 51741597 1% /

devtmpfs 251024 419 250605 1% /dev

tmpfs 253771 1 253770 1% /dev/shm

tmpfs 253771 747 253024 1% /run

tmpfs 253771 16 253755 1% /sys/fs/cgroup

/dev/sda1 102400 326 102074 1% /boot

tmpfs 253771 1 253770 1% /run/user/0

/dev/sdb1 103936 3 103933 1% /data

tmpfs 253771 2 253769 1% /mem

/dev/loop0 16 16 0 100% /mnt

[root@oldboyedu60-lnb ~]# mkdir test

[root@oldboyedu60-lnb ~]# touch test/{1..450000}

-bash: /usr/bin/touch: Argument list too long

参数列表过长（文件名过多）

[root@oldboyedu60-lnb ~]# mkdir test

[root@oldboyedu60-lnb ~]# touch test/{1..450000}

-bash: /usr/bin/touch: Argument list too long

[root@oldboyedu60-lnb ~]# echo test/{1..450000}|xargs touch

wc 统计文件信息行数单词数大小

wc -l 统计行数

[root@oldboyedu60-lnb ~]# ls test/* |xargs rm -f

-bash: /usr/bin/ls: Argument list too long

[root@oldboyedu60-lnb ~]# ls test/1* |xargs rm -f

[root@oldboyedu60-lnb ~]# ls test/2* |xargs rm -f

[root@oldboyedu60-lnb ~]# ls test/* |xargs rm -f

-bash: /usr/bin/ls: Argument list too long

[root@oldboyedu60-lnb ~]# ls test/3* |xargs rm -f

inode满了

df -h df -i

磁盘

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