N26-第七周

1、创建一个10G分区，并格式为ext4文件系统；
   (1) 要求其block大小为2048, 预留空间百分比为2, 卷标为MYDATA, 默认挂载属性包含acl；

   (2) 挂载至/data/mydata目录，要求挂载时禁止程序自动运行，且不更新文件的访问时间戳；

[root@localhost ~]# 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 0x151eee1f.

Command (m for help): n
Partition type:
   p   primary (0 primary, 0 extended, 4 free)
   e   extended
Select (default p): p
Partition number (1-4, default 1): 1
First sector (2048-41943039, default 2048): 
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-41943039, default 41943039): +10G
Partition 1 of type Linux and of size 10 GiB is set

Command (m for help): t  
Hex code (type L to list all codes): 83 

    [root@localhost ~]# mkfs.ext4 -b 2048 -m 2 -L MYDATA /dev/sdb1
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  
[root@localhost ~]# mount -o noexec,acl,noatime /dev/sdb1 /data/mydata/
    

        
    

    

        
    

2、创建一个大小为1G的swap分区，并创建好文件系统，并启用之；

[root@localhost ~]# mkswap /dev/sdb2 
Setting up swapspace version 1, size = 1048572 KiB
no label, UUID=fd915379-a879-409b-8343-5698350022e6
[root@localhost ~]# swapon  /dev/sdb2

3、写一个脚本
   (1)、获取并列出当前系统上的所有磁盘设备；

   (2)、显示每个磁盘设备上每个分区相关的空间使用信息；

#!/bin/bash
#
#
#
ls /dev/[s,h]d[a-z]
fdisk -l `ls /dev/[s,h]d[a-z]`   

4、总结RAID的各个级别及其组合方式和性能的不同；

    RAID0：将多块硬盘组合成一块硬盘使用，读写性能都有提升，磁盘利用率100%，无冗余能力，至少需要2块硬盘

    RAID1：将一份数据存储两份，读能力有提升，写能力下将，磁盘利用率50%，有冗余能力，至少需要两块硬盘

    RAID2、3、4:现在基本没有使用

    RAID5：将数据拆分存储并加入校验码技术，读写能力均有提升，磁盘利用率为 (磁盘数-1)/磁盘数，最多允许坏一块硬盘，至少需要3块硬盘 

    RAID10：将磁盘先做raid1后再做raid0，读写能力均有提升，磁盘利用率为50%，每组最多允许坏一块硬盘，至少需要4块硬盘

    RAID01：将磁盘先做raid0后再做raid1，读写能力均有提升，磁盘利用率为50%，每组最多允许坏一块硬盘，至少需要4块硬盘

    注：RAID 10在整体容错能力和恢复代价上比RAID 01更有优势

5、创建一个大小为10G的RAID1，要求有一个空闲盘，而且CHUNK大小为128k;

[root@localhost scripts]# mdadm -C /dev/md1 -n 2 -x 1 -c 128 -l 1 /dev/sdb1 /dev/sdb2 /dev/sdb3
mdadm: /dev/sdb1 appears to contain an ext2fs file system
       size=10485760K  mtime=Sat Mar  4 13:38:10 2017
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? 
Continue creating array? (y/n) y
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md1 started.
[root@localhost scripts]# mdadm -D /dev/md1 
/dev/md1:
        Version : 1.2
  Creation Time : Sat Mar  4 16:27:42 2017
     Raid Level : raid1
     Array Size : 5238784 (5.00 GiB 5.36 GB)
  Used Dev Size : 5238784 (5.00 GiB 5.36 GB)
   Raid Devices : 2
  Total Devices : 3
    Persistence : Superblock is persistent

    Update Time : Sat Mar  4 16:27:58 2017
          State : clean, resyncing 
 Active Devices : 2
Working Devices : 3
 Failed Devices : 0
  Spare Devices : 1

  Resync Status : 64% complete

           Name : localhost.localdomain:1  (local to host localhost.localdomain)
           UUID : 345d614a:1c8921d7:4a62d97c:6d9555cc
         Events : 10

    Number   Major   Minor   RaidDevice State
       0       8       17        0      active sync   /dev/sdb1
       1       8       18        1      active sync   /dev/sdb2

       2       8       19        -      spare   /dev/sdb3

6、创建一个大小为4G的RAID5设备，chunk大小为256k，格式化ext4文件系统，要求可开机自动挂载至/backup目录，而且不更新访问时间戳，且支持acl功能；

root@localhost scripts]# mdadm -C /dev/md5 -n 4 -c 256 -l 5 /dev/sdb1 /dev/sdb2 /dev/sdb3 /dev/sdb4
mdadm: /dev/sdb1 appears to contain an ext2fs file system
       size=10485760K  mtime=Sat Mar  4 13:38:10 2017
mdadm: /dev/sdb1 appears to be part of a raid array:
       level=raid1 devices=2 ctime=Sat Mar  4 16:27:42 2017
Continue creating array? y
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md5 started.
[root@localhost scripts]# mdadm -D /dev/md5 
/dev/md5:
        Version : 1.2
  Creation Time : Sat Mar  4 16:33:41 2017
     Raid Level : raid5
     Array Size : 3142656 (3.00 GiB 3.22 GB)
  Used Dev Size : 1047552 (1023.17 MiB 1072.69 MB)
   Raid Devices : 4
  Total Devices : 4
    Persistence : Superblock is persistent

    Update Time : Sat Mar  4 16:33:47 2017
          State : clean 
 Active Devices : 4
Working Devices : 4
 Failed Devices : 0
  Spare Devices : 0

         Layout : left-symmetric
     Chunk Size : 256K

           Name : localhost.localdomain:5  (local to host localhost.localdomain)
           UUID : afc5cf68:aa1f4f34:f3047c47:d0b6f61c
         Events : 18

    Number   Major   Minor   RaidDevice State
       0       8       17        0      active sync   /dev/sdb1
       1       8       18        1      active sync   /dev/sdb2
       2       8       19        2      active sync   /dev/sdb3
       4       8       20        3      active sync   /dev/sdb4
[root@localhost scripts]# echo "/dev/md5 /backup ext4 defaults,acl,noatime,nodiratime 0 0" >> /etc/fstab [root@localhost scripts]# mount -a

7、写一个脚本
   (1) 接受一个以上文件路径作为参数；
   (2) 显示每个文件拥有的行数；

   (3) 总结说明本次共为几个文件统计了其行数；

#!/bin/bash
#
#
#
SUM=$#
[[ $# -eq 0 ]] && echo "use $0 /path/tofilename ...."&& exit
while true;do
        NUM=`wc -l $1`
        echo $NUM 
        shift
        if [[ $# = 0 ]];then
        break
        fi
 done
 echo "file number is $SUM"                             

8、写一个脚本
   (1) 传递两个以上字符串当作用户名；
   (2) 创建这些用户；且密码同用户名；

   (3) 总结说明共创建了几个用户；

#!/bin/bash
#
#
#
SUM=$#
[[ $# -le 2 ]] && echo "use $0 /path/tofilename ...."&& exit

while true;do
  id $1 &>/dev/null && echo "$1 is exits"&& break
        useradd $1 &>/dev/null
        echo "$1"| passwd --stdin $1 &>/dev/null
        echo "create  user $1 successful "
        shift
        if [[ $# = 0 ]];then
        break
        fi
 done
 echo "create user number is $SUM"

9、写一个脚本，新建20个用户，visitor1-visitor20；计算他们的ID之和；

#!/bin/bash
#
#
#
SUM=0
for i in {1..20};do
        useradd vistor$i
        NUM=`id -u vistor$i`
        let SUM+=$NUM
done
echo $SUM                        

10、写一脚本，分别统计/etc/rc.d/rc.sysinit、/etc/rc.d/init.d/functions和/etc/fstab文件中以#号开头的行数之和，以及总的空白行数；

#!/bin/bash
#
#
#
NUM1=`grep "^[[:space:]]*$" /etc/fstab /etc/init.d/functions /etc/rc.d/rc.sysinit | wc -l`
NUM2=`grep "^#" /etc/fstab /etc/init.d/functions /etc/rc.d/rc.sysinit | wc -l`
echo "Blank line number is $NUM1"
echo "At the beginning of line No. # number is $NUM2"                                                                           

11、写一个脚本，显示当前系统上所有默认shell为bash的用户的用户名、UID以及此类所有用户的UID之和；

#!/bin/bash
#
#
#
SUM=0
grep "\<bash\>" /etc/passwd | awk -F: '{ OFS=" ";;print $1,$3 }'
for i in $(grep "\<bash\>" /etc/passwd | awk -F: '{print $3 }');do
        let SUM+=$i
done
echo $SUM
                                

12、写一个脚本，显示当前系统上所有，拥有附加组的用户的用户名；并说明共有多少个此类用户；

#!/bin/bash
#
#
#
grep "[^:]$" /etc/group|cut -d: -f 4

grep "[^:]$" /etc/group|cut -d: -f 4|wc -l

13、创建一个由至少两个物理卷组成的大小为20G的卷组；要求，PE大小为8M；而在卷组中创建一个大小为5G的逻辑卷mylv1，格式化为ext4文件系统，开机自动挂载至/users目录，支持acl；

[root@localhost ~]# 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 0xb68ed7fc.

Command (m for help): n
Partition type:
   p   primary (0 primary, 0 extended, 4 free)
   e   extended
Select (default p): p
Partition number (1-4, default 1): 1
First sector (2048-62914559, default 2048): 
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-62914559, default 62914559): +10G
Partition 1 of type Linux and of size 10 GiB is set

Command (m for help): n
Partition type:
   p   primary (1 primary, 0 extended, 3 free)
   e   extended
Select (default p):  
Using default response p
Partition number (2-4, default 2): 
First sector (20973568-62914559, default 20973568): 
Using default value 20973568
Last sector, +sectors or +size{K,M,G} (20973568-62914559, default 62914559): +10G
Partition 2 of type Linux and of size 10 GiB is set

Command (m for help): t
Partition number (1,2, default 2): 
Hex code (type L to list all codes): 8e
Changed type of partition 'Linux' to 'Linux LVM'

Command (m for help): t
Partition number (1,2, default 2): 1
Hex code (type L to list all codes): 8e
Changed type of partition 'Linux' to 'Linux LVM'

Command (m for help): w
The partition table has been altered!
[root@localhost ~]# pvcreate /dev/sdb1 /dev/sdb2
  Physical volume "/dev/sdb1" successfully created
  Physical volume "/dev/sdb2" successfully created
[root@localhost ~]# vgcreate myvg -s 8M /dev/sdb1 /dev/sdb2
  Volume group "myvg" successfully created

    [root@localhost ~]# lvcreate -n mylv1 -L  5G  myvg
  Logical volume "mylv1" created.
    

        [root@localhost ~]# mkfs.ext4 /dev/myvg/mylv1 
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
327680 inodes, 1310720 blocks
65536 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=1342177280
40 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks: 
 32768, 98304, 163840, 229376, 294912, 819200, 884736

Allocating group tables: done                            
Writing inode tables: done                            
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done 
        

            [root@localhost ~]# echo "/dev/myvg/mylv1 /users ext4 defaults,acl 0 0" >> /etc/fstab 
            

                
            
[root@localhost ~]# mount -a
        

    

14、新建用户magedu；其家目录为/users/magedu，而后su切换至此用户，复制多个文件至家目录；

useradd -d /users/magedu magedu
su - magedu
cp /etc/issue /etc/fstab .

15、扩展mylv1至9G，确保扩展完成后原有数据完全可用；

[root@localhost ~]# lvextend -L +4G /dev/myvg/mylv1 
  Size of logical volume myvg/mylv1 changed from 5.00 GiB (640 extents) to 9.00 GiB (1152 extents).
  Logical volume mylv1 successfully resized.
[root@localhost ~]# resize2fs /dev/myvg/mylv1 
resize2fs 1.42.9 (28-Dec-2013)
Resizing the filesystem on /dev/myvg/mylv1 to 2359296 (4k) blocks.
The filesystem on /dev/myvg/mylv1 is now 2359296 blocks long.

16、缩减mylv1至7G，确保缩减完成后原有数据完全可用；

[root@localhost ~]# umount /users
[root@localhost ~]# fsck -t ext4 -f /dev/myvg/mylv1 
fsck from util-linux 2.23.2
e2fsck 1.42.9 (28-Dec-2013)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/mapper/myvg-mylv1: 11/589824 files (0.0% non-contiguous), 75551/2359296 blocks
[root@localhost ~]# resize2fs -f /dev/myvg/mylv1 7G
resize2fs 1.42.9 (28-Dec-2013)
Resizing the filesystem on /dev/myvg/mylv1 to 1835008 (4k) blocks.
The filesystem on /dev/myvg/mylv1 is now 1835008 blocks long.
[root@localhost ~]# lvreduce -L -2G /dev/myvg/mylv1 
  WARNING: Reducing active logical volume to 7.00 GiB
  THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce mylv1? [y/n]: y
  Size of logical volume myvg/mylv1 changed from 9.00 GiB (1152 extents) to 7.00 GiB (896 extents).
  Logical volume mylv1 successfully resized.

17、对mylv1创建快照，并通过备份数据；要求保留原有的属主属组等信息；

# lvcreate -L 500M -p r -s mylv1-snapshot -n /dev/myvg1/mylv1                    
# mkidr /mnt/mylv_ss ; mount /dev/myvg1/mylv1-snapshot /mnt/mylv_ss
# cp -a /mnt/mylv_ss/*  /tmp                    
# umount /mnt/mylv_ss 
# lvremove /dev/myvg1/mylv1-snapshot