集中練習5-磁盤分區、文件系統掛載、RAID管理

1. 創建一個10G分區，并格式化為ext4文件系統；
(1) 要求其block大小為2048，預留空間百分比為2%，卷標為MYDATA，默認掛載屬性包含acl；
(2) 掛載至/data/mydata目錄，要求掛載時禁止程序自動執行，且不更新文件的訪問時間戳；
“`
/]# 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.

Command (m for help): n
All primary partitions are in use
Adding logical partition 6
First sector (31463424-209715199, default 31463424):
Using default value 31463424
Last sector, +sectors or +size{K,M,G} (31463424-209715199, default 209715199): +10G
Partition 6 of type Linux and of size 10 GiB is set

Command (m for help): p

Disk /dev/sdb: 107.4 GB, 107374182400 bytes, 209715200 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: 0x277399ec

Device Boot????? Start???????? End????? Blocks?? Id? System
/dev/sdb1??????????? 2048??? 20973567??? 10485760?? 83? Linux
/dev/sdb2??????? 20973568??? 23070719???? 1048576?? 82? Linux swap / Solaris
/dev/sdb3??????? 23070720??? 27265023???? 2097152?? 83? Linux
/dev/sdb4??????? 27265024?? 209715199??? 91225088??? 5? Extended
/dev/sdb5??????? 27267072??? 31461375???? 2097152?? 8e? Linux LVM
/dev/sdb6??????? 31463424??? 52434943??? 10485760?? 83? Linux

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.
~]# kpartx -af /dev/sdb

~]# mke2fs -t ext4 -b 2048 -L MYDATA -m 2 /dev/sdb6
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=MYDATA
OS type: Linux
Block size=2048 (log=1)
Fragment size=2048 (log=1)
Stride=0 blocks, Stripe width=0 blocks
655360 inodes, 5242880 blocks
104857 blocks (2.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=273678336
320 block groups
16384 blocks per group, 16384 fragments per group
2048 inodes per group
Superblock backups stored on blocks:
16384, 49152, 81920, 114688, 147456, 409600, 442368, 802816, 1327104,
2048000, 3981312

Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
“`
2. 創建一個大小為1G的swap分區，并創建好文件系統，并啟用之；
“`
~]# 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.

Command (m for help): n
All primary partitions are in use
Adding logical partition 7
First sector (52436992-209715199, default 52436992):
Using default value 52436992
Last sector, +sectors or +size{K,M,G} (52436992-209715199, default 209715199): +1G
Partition 7 of type Linux and of size 1 GiB is set

Command (m for help): t
Partition number (1-7, default 7): 7
Hex code (type L to list all codes): 82
Changed type of partition ‘Linux’ to ‘Linux swap / Solaris’

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.
~]# kpartx -af /dev/sdb
~]# free -m
total??????? used??????? free????? shared? buff/cache?? available
Mem:?????????? 7806???????? 182??????? 7404?????????? 8???????? 220??????? 7353
Swap:????????? 2048?????????? 0??????? 2048

~]# mkswap /dev/sdb7
Setting up swapspace version 1, size = 1048572 KiB
no label, UUID=e9426246-b5b3-48e6-b034-5ec5f26646a9
~]# swapon /dev/sdb7
~]# free -m
total??????? used??????? free????? shared? buff/cache?? available
Mem:?????????? 7806???????? 180??????? 7401?????????? 8???????? 224??????? 7353
Swap:????????? 3072?????????? 0??????? 3072
“`
3. 寫一個腳本
(1) 獲取并列出當前系統上的所有磁盤設備
(2) 顯示每個磁盤設備上每個分區相關的空間使用信息
“`
#!/bin/bash
#
for i in `fdisk -l | grep “^Disk /dev” | grep -o “/dev/[[:alpha:]]\+\>”`; do
echo -e “\n$i disk usage: \n”
fdisk -l $i | grep “^/dev/”
done
“`
4. 總結RAID的各個級別及其組合方式和性能的不同；

RAID級別 | 可用空間 | 允許壞盤個數 | 磁盤數限制 | 讀寫性能
————- | ———— | ———— | ————– | ————–
JBOD | Size = S1+S2+…+SN | 0 | 2+ | 讀寫性能均沒有變化
RAID0 | Size = 2 x min(S1,S2,…) | 0 | 2+ | 讀、寫性能均有提升
RAID1 | Size = min(S1,S2,S3…) | N-1 | 2+ | 讀性能有提升，寫性能略有下降
RAID4 | Size = (N-1) x min(S1,S2,…,SN) | 1 | 3+ | 讀、寫性能均有提升
RAID5 | Size = (N-1) x min(S1,S2,…,SN) | 1 | 3+ | 讀、寫性能均有提升
RAID6 | Size = (N-2) x min(S1,S2,…,SN) | 2 | 4+ | 讀、寫性能均有提升
RAID1+0 | Size = N x min(S1,S2,…,SN)/2 | 每個RAID1剩一塊健康盤即可 | 4+ | 讀、寫性能均有提升
RAID0+1 | Size = N x min(S1,S2,…,SN)/2 | RAID1有一個健康的RAID0組即可 | 4+ | 讀、寫性能均有提升

5. 創建一個大小為10G的RAID1，要求有一個空閑盤，而且CHUNK大小為128K；

“`
通過fdisk命令創建3個10G的分區
~]# fdisk /dev/sdb
/dev/sdb7??????? 52436992??? 73408511??? 10485760?? fd? Linux raid autodetect
/dev/sdb8??????? 73410560??? 94382079??? 10485760?? fd? Linux raid autodetect
/dev/sdb9??????? 94384128?? 115355647??? 10485760?? fd? Linux raid autodetect

~]# mdadm -C /dev/md0 -n 2 -x 1 -l 1 -c 256 /dev/sdb{7,8,9}
mdadm: Note: this array has metadata at the start and
may not be suitable as a boot device.? If you plan to
store ‘/boot’ on this device please ensure that
your boot-loader understands md/v1.x metadata, or use
–metadata=0.90
Continue creating array? y
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md0 started.

~]# mdadm -D /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Thu Oct 26 13:54:04 2017
Raid Level : raid1
Array Size : 10477568 (9.99 GiB 10.73 GB)
Used Dev Size : 10477568 (9.99 GiB 10.73 GB)
Raid Devices : 2
Total Devices : 3
Persistence : Superblock is persistent

Update Time : Thu Oct 26 13:54:56 2017
State : clean
Active Devices : 2
Working Devices : 3
Failed Devices : 0
Spare Devices : 1

Name : sapbcs.mageedu.com:0? (local to host sapbcs.mageedu.com)
UUID : 88dca9de:813c1f6b:a28ec904:b9f37d67
Events : 17

Number?? Major?? Minor?? RaidDevice State
0?????? 8?????? 23??????? 0????? active sync?? /dev/sdb7
1?????? 8?????? 24??????? 1????? active sync?? /dev/sdb8

2?????? 8?????? 25??????? –????? spare?? /dev/sdb9
“`

6. 創建一個大小為4G的RAID5設備，CHUNK大小為256K，格式化為ext4文件系統，要求可開機自動掛載至/backup目錄，而且不更新訪問時間戳，且支持acl功能

“`
~]# fdisk /dev/sdb
新建4個4G分區，并調整格式為fd
/dev/sdb10????? 115357696?? 123746303???? 4194304?? fd? Linux raid autodetect
/dev/sdb11????? 123748352?? 132136959???? 4194304?? fd? Linux raid autodetect
/dev/sdb12????? 132139008?? 140527615???? 4194304?? fd? Linux raid autodetect
/dev/sdb13????? 140529664?? 148918271???? 4194304?? fd? Linux raid autodetect

~]# mdadm -C /dev/md1 -n 3 -x 1 -l 5 -c 256 /dev/sdb{10,11,12,13}
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md1 started.

~]# mke2fs -t ext4 /dev/md1

~]# vim /etc/fstab
/dev/md1????????? /backup??????????? ext4????????? defaults,acl,noatime?? 0? 0
“`
7. 寫一個腳本
(1) 接受一個以上文件路徑作為參數；
(2) 顯示每個文件擁有的行數；
(3) 總結說明本次共為幾個文件統計了行數；
“`
#!/bin/bash
#
if [ $# -lt 1 ];then
echo “Please input at least one path.”
exit 1
fi
for i in `seq 1 $#`; do
file=`echo $@ | cut -d’ ‘ -f$i`
lines=`wc -l $file | cut -d’ ‘ -f1`
echo “There are $lines lines in $file.”
done
echo “There are $# files counted by this script.”

~]# ./count.sh /etc/fstab /etc/rc.d/init.d/functions
There are 12 lines in /etc/fstab.
There are 654 lines in /etc/rc.d/init.d/functions.
There are 2 files counted by this script.
“`
8. 寫一個腳本
(1) 傳遞兩個以上字符串當作用戶名；
(2) 創建這些用戶，且密碼同用戶名；
(3) 總結說明共創建了幾個用戶；
“`
#!/bin/bash
#
if [ $# -lt 2 ]; then
echo “You must input at least two username.”
exit
fi

let skipnum=0

for i in `seq 1 $#`; do
user_name=`echo $@ | cut -d’ ‘ -f$i`
if id $user_name &> /dev/null; then
skipnum=$(($skipnum+1))
echo “User $user_name already exist in system.”
else
useradd $user_name &> /dev/null
echo $user_name | passwd $user_name –stdin &> /dev/null
echo “User $user_name has been created.”
fi
done

let sum=$(($#-$skipnum))
echo “There are $sum users created by this script.”
“`
9. 寫一個腳本
創建20個用戶，visitor1-visitor20；計算他們的ID之和；
“`
#!/bin/bash
#
let sum=0

for i in `seq 1 20`; do
id visitor$i &> /dev/null || useradd visitor$i &> /dev/null
let User_id=`id -u visitor$i`
sum=$(($sum+$User_id))
done

echo “User ID sum is $sum.”
“`