第七周

1、破坏mbr表并修复-

• 备份分区表,拷贝到远程主机上去，确认备份成功。

  [root@centos8 ~]$dd if=/dev/sda of=/data/dpt.img bs=1 count=64 skip=446
  [root@centos8 ~]scp /data/dpt.img 10.0.07:/data
  [root@centos7 ~]# hexdump -C /data/dpt.img 
  00000000  80 04 01 04 83 fe c2 ff  00 08 00 00 00 00 20 00  |.............. .|
  00000010  00 fe c2 ff 83 fe c2 ff  00 08 20 00 00 00 80 0c  |.......... .....|
  00000020  00 fe c2 ff 83 fe c2 ff  00 08 a0 0c 00 00 40 06  |..............@.|
  00000030  00 fe c2 ff 05 fe c2 ff  00 08 e0 12 00 f8 1f 06  |................|
  00- 000040
  
  

• 破坏MBR分区表

  [root@centos8 ~]$dd if=/dev/zero of=/dev/sda bs=1 count=64 seek=446
  64+0 records in
  64+0 records out
  64 bytes copied, 0.000166037 s, 385 kB/s
  

• 重启电脑进入，光盘引导进入rescue模式。

  //当前网络连接没有，为网卡配置IP
  ip a //查看网络接口
  ip add a 10.0.0.8/24 dev ens33   //添加IP
  scp 10.0.07:/data/dpt.img .      //备份文件拷贝到本地
  dd if=dpt.img of=/dev/sda count=64 bs=1 seek=446   //恢复分区表
  hexdump -C -n 512 /dev/sda                //进行确认
  reboot                                    //重启，系统分区修复
  

2、总结RAID的各个级别及其组合方式和性能的不同。

常用RAID

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

• 使用 fdisk /dev/sda建立一个2G的分区

  Command (m for help): n   
  All primary partitions are in use.
  Adding logical partition 6
  First sector (320870400-419430399, default 320870400): 
  Last sector, +sectors or +size{K,M,G,T,P} (320870400-419430399, default 419430399): +2G
  
  Command (m for help): p
  Disk /dev/sda: 200 GiB, 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
  Disklabel type: dos
  Disk identifier: 0xe210e0a7
  
  Device     Boot     Start       End   Sectors  Size Id Type
  /dev/sda6       320870400 325064703   4194304    2G 83 Linux
  
  Filesystem/RAID signature on partition -6 will be wiped.
  
  

• 格式化分区m

  [root@centos8 ~]$mkfs.ext4 -b 2024 -m 1 -L TEST /dev/sda6
  [root@centos8 ~]$blkid /dev/sda6
  /dev/sda6: LABEL="TEST" UUID="a1baf327-7be5-4bee-889f-d9b4afb8f2f2" TYPE="ext4" PARTUUID="e210e0a7-06"
  

• 编辑/etc/fstab，添加

  UUID=a1baf327-7be5-4bee-889f-d9b4afb8f2f2 /test ext4 defaults,acl   0 0 
  
  

• 测试acl成功启用

  [root@centos8 ~]$mount -a
  [root@centos8 test]$setfacl -m u:user4:rwx /test/dir1/
  [root@centos8 test]$getfacl /test/dir1/
  getfacl: Removing leading '/' from absolute path names
  # file: test/dir1/
  # owner: root
  # group: root
  user::rwx
  user:user4:rwx
  group::r-x
  mask::rwx
  other::r-x
  [root@centos8 test]$ll 
  total 2
  drwxrwxr-x+ 2 root root 1024 Jan  6 22:04 dir1
  
  

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

• 在/dev/sda建立两个10G分区，

  All primary partitions are in use.
  Adding logical partition 6
  First sector (320870400-419430399, default 320870400): 
  Last sector, +sectors or +size{K,M,G,T,P} (320870400-419430399, default 419430399): +10G 
  Created a new partition 6 of type 'Linux' and of size 10 GiB.
  Value out of range.
  First sector (362815488-419430399, default 362815488): 
  Last sector, +sectors or +size{K,M,G,T,P} (362815488-419430399, default 419430399): +10G
  Device     Boot     Start       End   Sectors  Size Id Type
  /dev/sda6       320870400 362813439  41943040   10G 83 Linux
  /dev/sda7       362815488 404758527  41943040   10G 83 Linux
  

• 激活分区

  [root@centos8 ~]$partprobe /dev/sda
  

• 建立testvg逻辑卷组

  [root@centos8 ~]$vgcreate testvg -s 16M /dev/sda6 /dev/sda7
    Physical volume "/dev/sda6" successfully created.
    Physical volume "/dev/sda7" successfully created.
    Volume group "testvg" successfully created
  

• 建立testlv逻辑卷,假定按xfs分区

  [root@centos8 ~]$lvcreate -n testlv -L 5G testvg 
    Logical volume "testlv" created.
  [root@centos8 ~]$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=1, sparse=1, rmapbt=0
           =                       reflink=1
  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
  
  

• 建立 /users目录，编辑/etc/fstab，添加如下行

  mkdir /users
  /dev/testvg/testlv /users xfs defaults 0 0