第五周
1、破坏mbr表并修复
1.1 备份
1.1.1 使用dd工具备份MBR
[root@centos7 ~]# dd if=/dev/sda of=/data/dpt.img bs=1 count=64 skip=446
1.1.2 将备份文件保存在另一台主机
[root@centos7 ~]# scp /data/dpt.img 192.168.31.185:/data/dpt.img
1.2 破坏：索引部分任意地方破坏都启动不了，前面因为只备份446开始的64字节
[root@centos7 ~]# dd if=/dev/zero of=/dev/sda bs=1 count=64 seek=446
注：skip是跳过if中的前多少，seek是跳过of中的前多少
1.3 救援
1.3.1 reboot
1.3.2 按ESC进入启动菜单，选择3进入光盘启动
1.3.3 然后选择Troubleshooting
1.3.4 再选择Rescue a CentOS system
1.3.5 然后选择3，进入shell模式
1.3.6 配置IP地址
ip addr add 192.168.31.175/24 dev ens33
1.3.7 拷贝备份文件到当前目录
scp 192.168.31.185:/data/dpt.img .
1.3.8 使用dd工具恢复MBR分区
dd if=dpt.img of=/dev/sda bs=1 seek=446
2、总结RAID的各个级别及其组合方式和性能的不同。
3、创建一个2G的文件系统，块大小为2048byte，预留1%可用空间,文件系统ext4，卷标为TEST，要求此分区开机后自动挂载至/test目录，且默认有acl挂载选项。
3.1 查看块设备信息
[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 100G 0 part /
└─sda3 8:3 0 50G 0 part /data
sdb 8:16 0 50G 0 disk
sr0 11:0 1 1024M 0 rom
3.2 在sdb磁盘上创建大小为2G的分区
[root@centos7 ~]# 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 0xf2dabdc7.
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):
First sector (2048-104857599, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-104857599, default 104857599): +2G
Partition 1 of type Linux and of size 2 GiB is set
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
3.3 创建文件系统
[root@centos7 ~]# mkfs.ext4 -b 2048 -m 1 -L TEST /dev/sdb1
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=TEST
OS type: Linux
Block size=2048 (log=1)
Fragment size=2048 (log=1)
Stride=0 blocks, Stripe width=0 blocks
131072 inodes, 1048576 blocks
10485 blocks (1.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=269484032
64 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
Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
3.4 查看UUID信息
[root@centos7 ~]# blkid
/dev/sdb1: LABEL="TEST" UUID="12da7d7c-5813-4e19-b234-49dca7c60cf0" TYPE="ext4"
3.5 将分区挂载到指定文件夹，在/etc/fstab文件中添加以下内容
UUID=12da7d7c-5813-4e19-b234-49dca7c60cf0 /test ext4 acl 0 0
3.6 创建目标文件夹，使配置文件生效
[root@centos7 ~]# mkdir /test
[root@centos7 ~]# mount -a
3.7 查看最后结果
[root@centos7 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
devtmpfs 900M 0 900M 0% /dev
tmpfs 910M 0 910M 0% /dev/shm
tmpfs 910M 9.6M 901M 2% /run
tmpfs 910M 0 910M 0% /sys/fs/cgroup
/dev/sda2 100G 1.8G 99G 2% /
/dev/sda3 50G 33M 50G 1% /data
/dev/sda1 1014M 142M 873M 14% /boot
tmpfs 182M 0 182M 0% /run/user/0
/dev/sdb1 2.0G 9.1M 1.9G 1% /test
4、创建一个至少有两个PV组成的大小为20G的名为testvg的VG;要求PE大小为16MB, 而后在卷组中创建大小为5G的逻辑卷testlv;挂载至/users目录。
4.1 查看块设备信息
[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 100G 0 part /
└─sda3 8:3 0 50G 0 part /data
sdb 8:16 0 50G 0 disk
└─sdb1 8:17 0 2G 0 part /test
sr0 11:0 1 1024M 0 rom
4.2 创建分区
4.2.1 在sda上创建大小为5G的分区
[root@centos7 ~]# fdisk /dev/sda
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
Partition type:
p primary (3 primary, 0 extended, 1 free)
e extended
Select (default e):
Using default response e
Selected partition 4
First sector (316672000-419430399, default 316672000):
Using default value 316672000
Last sector, +sectors or +size{K,M,G} (316672000-419430399, default 419430399):
Using default value 419430399
Partition 4 of type Extended and of size 49 GiB is set
Command (m for help): n
All primary partitions are in use
Adding logical partition 5
First sector (316674048-419430399, default 316674048):
Using default value 316674048
Last sector, +sectors or +size{K,M,G} (316674048-419430399, default 419430399): +5G
Partition 5 of type Linux and of size 5 GiB is set
Command (m for help): t
Partition number (1-5, default 5):
Hex code (type L to list all codes): 8e
Changed type of partition 'Linux' to 'Linux LVM'
Command (m for help): p
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: 0x0009d5d8
Device Boot Start End Blocks Id System
/dev/sda1 * 2048 2099199 1048576 83 Linux
/dev/sda2 2099200 211814399 104857600 83 Linux
/dev/sda3 211814400 316671999 52428800 83 Linux
/dev/sda4 316672000 419430399 51379200 5 Extended
/dev/sda5 316674048 327159807 5242880 8e Linux LVM
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table. The new table will be used at
the next reboot or after you run partprobe(8) or kpartx(8)
Syncing disks.
4.2.2 在sdb上创建大小为15G的分区
[root@centos7 ~]# 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
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 (4196352-104857599, default 4196352):
Using default value 4196352
Last sector, +sectors or +size{K,M,G} (4196352-104857599, default 104857599): +15G
Partition 2 of type Linux and of size 15 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): p
Disk /dev/sdb: 53.7 GB, 53687091200 bytes, 104857600 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: 0xf2dabdc7
Device Boot Start End Blocks Id System
/dev/sdb1 2048 4196351 2097152 83 Linux
/dev/sdb2 4196352 35653631 15728640 8e Linux LVM
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table. The new table will be used at
the next reboot or after you run partprobe(8) or kpartx(8)
Syncing disks.
[root@centos7 ~]# partprobe
[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 100G 0 part /
├─sda3 8:3 0 50G 0 part /data
├─sda4 8:4 0 1K 0 part
└─sda5 8:5 0 5G 0 part
sdb 8:16 0 50G 0 disk
├─sdb1 8:17 0 2G 0 part /test
└─sdb2 8:18 0 15G 0 part
sr0 11:0 1 1024M 0 rom
4.3 创建物理卷（pv）
4.3.1 创建物理卷
[root@centos7 ~]# pvcreate /dev/sda5 /dev/sdb2
Physical volume "/dev/sda5" successfully created.
Physical volume "/dev/sdb2" successfully created.
4.3.2 查看物理卷
[root@centos7 ~]# pvs
PV VG Fmt Attr PSize PFree
/dev/sda5 lvm2 --- 5.00g 5.00g
/dev/sdb2 lvm2 --- 15.00g 15.00g
[root@centos7 ~]# pvdisplay
"/dev/sdb2" is a new physical volume of "15.00 GiB"
--- NEW Physical volume ---
PV Name /dev/sdb2
VG Name
PV Size 15.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID 6IBD3k-oHa8-ddBq-ugYj-bQxf-vcw5-d1tpbn
"/dev/sda5" is a new physical volume of "5.00 GiB"
--- NEW Physical volume ---
PV Name /dev/sda5
VG Name
PV Size 5.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID yDwMO0-LRLy-BJlR-Ol8U-9u6g-J6Gk-bCRrNU
4.4 创建卷组（vg）
4.4.1 创建卷组
[root@centos7 ~]# vgcreate -s 16M testvg /dev/sda5 /dev/sdb2
Volume group "testvg" successfully created
4.4.2 查看卷组
[root@centos7 ~]# vgs
VG #PV #LV #SN Attr VSize VFree
testvg 2 0 0 wz--n- <19.97g <19.97g
[root@centos7 ~]# vgdisplay
--- Volume group ---
VG Name testvg
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 1
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 0
Open LV 0
Max PV 0
Cur PV 2
Act PV 2
VG Size <19.97 GiB
PE Size 16.00 MiB
Total PE 1278
Alloc PE / Size 0 / 0
Free PE / Size 1278 / <19.97 GiB
VG UUID VZp5Sl-XPww-sNHs-CiKV-nsjx-EVCR-Rebd1A
4.5 创建逻辑卷（lv）
4.5.1 创建逻辑卷
[root@centos7 ~]# lvcreate -n testlv -L 5G testvg
Logical volume "testlv" created.
4.5.2 查看逻辑卷
[root@centos7 ~]# lvs
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
testlv testvg -wi-a----- 5.00g
[root@centos7 ~]# lvdisplay
--- Logical volume ---
LV Path /dev/testvg/testlv
LV Name testlv
VG Name testvg
LV UUID WjHFtk-kXet-VA8y-SAW5-pV63-FvuN-Hvf4IF
LV Write Access read/write
LV Creation host, time centos7, 2021-07-11 16:12:32 +0800
LV Status available
# open 0
LV Size 5.00 GiB
Current LE 320
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:0
4.6 创建文件系统
[root@centos7 ~]# mkfs.xfs /dev/testvg/testlv
meta-data=/dev/testvg/testlv isize=512 agcount=4, agsize=327680 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0, sparse=0
data = bsize=4096 blocks=1310720, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal log bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
4.7 创建挂载点
4.7.1 创建挂载目录
[root@centos7 ~]# mkdir /users
4.7.2 查看UUID
[root@centos7 ~]# blkid
/dev/mapper/testvg-testlv: UUID="ebe260a4-5f2e-43e9-a96c-4d94610c0281" TYPE="xfs"
4.7.3 在/etc/fstab文件中添加以下内容
UUID=ebe260a4-5f2e-43e9-a96c-4d94610c0281 /users xfs defaults 0 0
4.7.4 使配置文件生效
[root@centos7 ~]# mount -a
4.8 查看最终结果
[root@centos7 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
devtmpfs 900M 0 900M 0% /dev
tmpfs 910M 0 910M 0% /dev/shm
tmpfs 910M 9.6M 901M 2% /run
tmpfs 910M 0 910M 0% /sys/fs/cgroup
/dev/sda2 100G 1.8G 99G 2% /
/dev/sda3 50G 33M 50G 1% /data
/dev/sda1 1014M 142M 873M 14% /boot
tmpfs 182M 0 182M 0% /run/user/0
/dev/sdb1 2.0G 9.1M 1.9G 1% /test
/dev/mapper/testvg-testlv 5.0G 33M 5.0G 1% /users
5、简述OSI七层模型和TCP/IP五层模型
