1、磁盘lvm管理，完成下面要求，并写出详细过程：
1) 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
准备两个10G的磁盘sdb,sdc或分区 [root@linux-node2-202 ~]# fdisk -l|grep sd Disk /dev/sda: 53.7 GB, 53687091200 bytes, 104857600 sectors /dev/sda1 * 2048 411647 204800 83 Linux /dev/sda2 411648 104857599 52222976 8e Linux LVM Disk /dev/sdb: 10.7 GB, 10737418240 bytes, 20971520 sectors Disk /dev/sdc: 10.7 GB, 10737418240 bytes, 20971520 sectors 使用sdb和sdc两个磁盘创建PV [root@linux-node2-202 ~]# pvcreate /dev/sd{b,c} Physical volume "/dev/sdb" successfully created. Physical volume "/dev/sdc" successfully created. [root@linux-node2-202 ~]# pvs PV VG Fmt Attr PSize PFree /dev/sda2 centos lvm2 a-- 49.80g 0 /dev/sdb lvm2 --- 10.00g 10.00g /dev/sdc lvm2 --- 10.00g 10.00g 创建名为testvg的VG，要求PE大小 为16MB [root@linux-node2-202 ~]# vgcreate -s 16M testvg /dev/sd{b,c} Volume group "testvg" successfully created [root@linux-node2-202 ~]# vgs VG #PV #LV #SN Attr VSize VFree centos 1 2 0 wz--n- 49.80g 0 testvg 2 0 0 wz--n- <19.97g <19.97g 在卷组中创建大小为5G的逻 辑卷testlv [root@linux-node2-202 ~]# lvcreate -n testlv -L 5G testvg Logical volume "testlv" created. [root@linux-node2-202 ~]# lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert root centos -wi-ao---- 47.80g swap centos -wi-ao---- 2.00g testlv testvg -wi-a----- 5.00g 挂载至/users目录 [root@linux-node2-202 ~]# mkdir /users [root@linux-node2-202 ~]# mkfs.xfs /dev/mapper/testvg-testlv [root@linux-node2-202 ~]# mount /dev/mapper/testvg-testlv /users 永久挂载 [root@linux-node2-202 ~]# blkid /dev/mapper/testvg-testlv: UUID="c20abbbc-6714-4bb3-b6b3-039e49ebb1ad" TYPE="xfs" [root@linux-node2-202 ~]# vim /etc/fstab 添加 UUID=c20abbbc-6714-4bb3-b6b3-039e49ebb1ad /users xfs defaults 0 0 [root@linux-node2-202 ~]# mount -a [root@linux-node2-202 ~]# df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/centos-root 48G 9.4G 39G 20% / devtmpfs 899M 0 899M 0% /dev tmpfs 911M 0 911M 0% /dev/shm tmpfs 911M 9.6M 902M 2% /run tmpfs 911M 0 911M 0% /sys/fs/cgroup /dev/sda1 197M 120M 77M 61% /boot tmpfs 183M 0 183M 0% /run/user/0 /dev/mapper/testvg-testlv 5.0G 33M 5.0G 1% /users
[root@linux-node2-202 ~]# vgdisplay testvg|egrep -io "(pe|vg).*size.*"
VG Size <19.97 GiB
PE Size 16.00 MiB
PE / Size 320 / 5.00 GiB
PE / Size 958 / <14.97 GiB
2) 扩展testlv至7G，要求archlinux用户的文件不能丢失
创建archlinux用户 [root@linux-node2-202 ~]# useradd archlinux -d /users/archlinux [root@linux-node2-202 ~]# su - archlinux [archlinux@linux-node2-202 ~]$ pwd /users/archlinux [archlinux@linux-node2-202 ~]$ cp -R /var/log . [archlinux@linux-node2-202 ~]$ tree . └── log ├── anaconda ├── audit ├── cobbler │ ├── anamon │ ├── cobbler.log │ ├── install.log │ ├── kicklog │ ├── syslog │ └── tasks │ ├── 2019-07-22_195442_get_loaders.log │ ├── 2019-07-22_195512_sync.log │ ├── 2019-07-22_195653_sync.log │ ├── 2019-07-22_195950_import.log │ ├── 2019-07-22_200256_import.log │ ├── 2019-07-22_200523_import.log │ └── 2019-07-22_200652_sync.log ├── dmesg ├── dmesg.old ├── firewalld ├── grubby_prune_debug ├── httpd ├── lastlog ├── rhsm ├── tuned │ └── tuned.log ├── vmware-vgauthsvc.log.0 ├── vmware-vmsvc.log └── wtmp 11 directories, 18 files [archlinux@linux-node2-202 ~]$ du -sh log 2.2M log 扩展testlv至7G，要求archlinux用户的文件不能丢失 [root@linux-node2-202 ~]# vgdisplay testvg|grep Size VG Size <19.97 GiB PE Size 16.00 MiB Alloc PE / Size 320 / 5.00 GiB Free PE / Size 958 / <14.97 GiB [root@linux-node2-202 ~]# lvdisplay /dev/testvg/testlv|grep Size LV Size 5.00 GiB 可以看到当前的LV大小为5G，VG可分配的大小为15G 需要再扩容2G [root@linux-node2-202 ~]# lvextend -L +2G /dev/mapper/testvg-testlv Size of logical volume testvg/testlv changed from 5.00 GiB (320 extents) to 7.00 GiB (448 extents). Logical volume testvg/testlv successfully resized. [root@linux-node2-202 ~]# lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert root centos -wi-ao---- 47.80g swap centos -wi-ao---- 2.00g testlv testvg -wi-ao---- 7.00g [root@linux-node2-202 ~]# vgs VG #PV #LV #SN Attr VSize VFree centos 1 2 0 wz--n- 49.80g 0 testvg 2 1 0 wz--n- <19.97g <12.97g [root@linux-node2-202 ~]# tree /users/archlinux/ /users/archlinux/ └── log ├── anaconda ├── audit ├── cobbler │ ├── anamon │ ├── cobbler.log │ ├── install.log │ ├── kicklog │ ├── syslog │ └── tasks │ ├── 2019-07-22_195442_get_loaders.log │ ├── 2019-07-22_195512_sync.log │ ├── 2019-07-22_195653_sync.log │ ├── 2019-07-22_195950_import.log │ ├── 2019-07-22_200256_import.log │ ├── 2019-07-22_200523_import.log │ └── 2019-07-22_200652_sync.log ├── dmesg ├── dmesg.old ├── firewalld ├── grubby_prune_debug ├── httpd ├── lastlog ├── rhsm ├── tuned │ └── tuned.log ├── vmware-vgauthsvc.log.0 ├── vmware-vmsvc.log └── wtmp 11 directories, 18 files [root@linux-node2-202 ~]# du -sh /users/archlinux/ 2.3M /users/archlinux/
3) 收缩testlv至3G，要求archlinux用户的文件不能丢失
缩减逻辑卷需要先取消挂载，再进行操作 [root@linux-node2-202 ~]# umount /users [root@linux-node2-202 ~]# lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert root centos -wi-ao---- 47.80g swap centos -wi-ao---- 2.00g testlv testvg -wi-a----- 7.00g #Xfs系统不支持缩减 检查文件完整性 [root@linux-node2-202 ~]# e2fsck -f -y /dev/mapper/testvg-testlv 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/testvg-testlv: 11/458752 files (0.0% non-contiguous), 69631/1835008 blocks 收缩testlv至3G，要求archlinux用户的文件不能丢失 先设置文件系统大小 [root@linux-node2-202 ~]# resize2fs /dev/mapper/testvg-testlv 3G resize2fs 1.42.9 (28-Dec-2013) Resizing the filesystem on /dev/mapper/testvg-testlv to 786432 (4k) blocks. The filesystem on /dev/mapper/testvg-testlv is now 786432 blocks long. 缩减逻辑卷 [root@linux-node2-202 ~]# lvreduce -L 3G /dev/mapper/testvg-testlv WARNING: Reducing active logical volume to 3.00 GiB. THIS MAY DESTROY YOUR DATA (filesystem etc.) Do you really want to reduce testvg/testlv? [y/n]: y Size of logical volume testvg/testlv changed from 7.00 GiB (448 extents) to 3.00 GiB (192 extents). Logical volume testvg/testlv successfully resized. [root@linux-node2-202 ~]# lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert root centos -wi-ao---- 47.80g swap centos -wi-ao---- 2.00g testlv testvg -wi-a----- 3.00g [root@linux-node2-202 ~]# lvdisplay /dev/testvg/testlv|grep Size LV Size 3.00 GiB [root@linux-node2-202 ~]# tree /users/archlinux/ /users/archlinux/ └── log ├── anaconda ├── audit ├── cobbler │ ├── anamon │ ├── cobbler.log │ ├── install.log │ ├── kicklog │ ├── syslog │ └── tasks │ ├── 2019-07-22_195442_get_loaders.log │ ├── 2019-07-22_195512_sync.log │ ├── 2019-07-22_195653_sync.log │ ├── 2019-07-22_195950_import.log │ ├── 2019-07-22_200256_import.log │ ├── 2019-07-22_200523_import.log │ └── 2019-07-22_200652_sync.log ├── dmesg ├── dmesg.old ├── firewalld ├── grubby_prune_debug ├── httpd ├── lastlog ├── rhsm ├── tuned │ └── tuned.log ├── vmware-vgauthsvc.log.0 ├── vmware-vmsvc.log └── wtmp 11 directories, 18 files [root@linux-node2-202 ~]# du -sh /users/archlinux/ 2.3M /users/archlinux/
4) 对testlv创建快照，并尝试基于快照备份数据，验证快照的功能
[root@linux-node2-202 ~]# lvcreate -n testlv_snap -s -p r -L 5G /dev/mapper/testvg-testlv lvcreate 创建 名称为testlv_snap 快照 属性-只读 容量5G 目标/dev/mapper/testvg-testlv Reducing COW size 5.00 GiB down to maximum usable size <3.02 GiB. Logical volume "testlv_snap" created. [root@linux-node2-202 ~]# lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert root centos -wi-ao---- 47.80g swap centos -wi-ao---- 2.00g testlv testvg owi-aos--- 3.00g testlv_snap testvg sri-a-s--- <3.02g testlv 0.01 [root@linux-node2-202 ~]# lvdisplay /dev/test*|grep snap LV snapshot status source of testlv_snap [active] LV Path /dev/testvg/testlv_snap LV Name testlv_snap LV snapshot status active destination for testlv Allocated to snapshot 0.01% [root@linux-node2-202 ~]# blkid |grep testvg /dev/mapper/testvg-testlv: UUID="fe421f83-f353-4ad3-a571-47e808c5dd5d" TYPE="ext4" /dev/mapper/testvg-testlv_snap: UUID="fe421f83-f353-4ad3-a571-47e808c5dd5d" TYPE="ext4" 可以看到两个uuid相同 验证快照的功能 挂载快照 [root@linux-node2-202 ~]# mount /dev/mapper/testvg-testlv_snap /mnt/snap mount: /dev/mapper/testvg-testlv_snap is write-protected, mounting read-only [root@linux-node2-202 ~]# tree /mnt/snap /mnt/snap ├── archlinux │ └── log │ ├── anaconda │ ├── audit │ ├── cobbler │ │ ├── anamon │ │ ├── cobbler.log │ │ ├── install.log │ │ ├── kicklog │ │ ├── syslog │ │ └── tasks │ │ ├── 2019-07-22_195442_get_loaders.log │ │ ├── 2019-07-22_195512_sync.log │ │ ├── 2019-07-22_195653_sync.log │ │ ├── 2019-07-22_195950_import.log │ │ ├── 2019-07-22_200256_import.log │ │ ├── 2019-07-22_200523_import.log │ │ └── 2019-07-22_200652_sync.log │ ├── dmesg │ ├── dmesg.old │ ├── firewalld │ ├── grubby_prune_debug │ ├── httpd │ ├── lastlog │ ├── rhsm │ ├── tuned │ │ └── tuned.log │ ├── vmware-vgauthsvc.log.0 │ ├── vmware-vmsvc.log │ └── wtmp └── lost+found 13 directories, 18 files [root@linux-node2-202 ~]# du -sh /mnt/snap 2.3M /mnt/snap 删除源目录中的文件 [root@linux-node2-202 ~]# rm -rf /users/archlinux/log/httpd/ [root@linux-node2-202 ~]# rm -f /users/archlinux/log/* [root@linux-node2-202 ~]# tree /users/archlinux/ /users/archlinux/ └── log ├── anaconda ├── audit ├── cobbler │ ├── anamon │ ├── cobbler.log │ ├── install.log │ ├── kicklog │ ├── syslog │ └── tasks │ ├── 2019-07-22_195442_get_loaders.log │ ├── 2019-07-22_195512_sync.log │ ├── 2019-07-22_195653_sync.log │ ├── 2019-07-22_195950_import.log │ ├── 2019-07-22_200256_import.log │ ├── 2019-07-22_200523_import.log │ └── 2019-07-22_200652_sync.log ├── rhsm └── tuned └── tuned.log 10 directories, 10 files [root@linux-node2-202 ~]# du -sh /users/archlinux/ 2.0M /users/archlinux/ 还原快照 取消源和快照的挂载 [root@linux-node2-202 ~]# umount /users [root@linux-node2-202 ~]# umount /mnt/snap 还原快照 [root@linux-node2-202 ~]# lvconvert --merge /dev/mapper/testvg-testlv_snap Merging of volume testvg/testlv_snap started. testvg/testlv: Merged: 100.00% 验证数据 [root@linux-node2-202 ~]# du -sh /users/archlinux/ 2.3M /users/archlinux/ [root@linux-node2-202 ~]# du -sh /users/archlinux/ 2.3M /users/archlinux/ [root@linux-node2-202 ~]# tree /users/archlinux/ /users/archlinux/ └── log ├── anaconda ├── audit ├── cobbler │ ├── anamon │ ├── cobbler.log │ ├── install.log │ ├── kicklog │ ├── syslog │ └── tasks │ ├── 2019-07-22_195442_get_loaders.log │ ├── 2019-07-22_195512_sync.log │ ├── 2019-07-22_195653_sync.log │ ├── 2019-07-22_195950_import.log │ ├── 2019-07-22_200256_import.log │ ├── 2019-07-22_200523_import.log │ └── 2019-07-22_200652_sync.log ├── dmesg ├── dmesg.old ├── firewalld ├── grubby_prune_debug ├── httpd ├── lastlog ├── rhsm ├── tuned │ └── tuned.log ├── vmware-vgauthsvc.log.0 ├── vmware-vmsvc.log └── wtmp 11 directories, 18 files 创建快照(XFS)系统 lvcreate -n lv_mysql_snap -s -L 1G -p r /dev/mapper/testvg-testlv mount /dev/mapper/testvg-testlv /mnt/snap/ #直接挂载不上去 mount -o nouuid /dev/mapper/testvg-testlv_snap /mnt/snap/ #加上nouuid选项 还原快照(XFS) 取消所有相关挂载 lvconvert --merge /dev/mapper/testvg-testlv_snap
2、创建一个可用空间为1G的RAID1设备，文件系统为ext4，有一个空闲盘，开机可自动挂载至/backup目录
创建3个1G的分区 [root@linux-node2-202 ~]# fdisk -l /dev/sdb Disk /dev/sdb: 10.7 GB, 10737418240 bytes, 20971520 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: 0xdf25804a Device Boot Start End Blocks Id System /dev/sdb1 2048 2099199 1048576 83 Linux /dev/sdb2 2099200 4196351 1048576 83 Linux /dev/sdb3 4196352 6293503 1048576 83 Linux 创建raid 1 sdb3 作为空闲盘 [root@linux-node2-202 ~]# mdadm -C -a yes /dev/md0 -l 1 -n 2 /dev/sdb{1,2} -x 1 -c 1024 /dev/sdb3 [root@linux-node2-202 ~]# mdadm -D /dev/md0 /dev/md0: Version : 1.2 Creation Time : Tue Jul 23 19:25:54 2019 Raid Level : raid1 Array Size : 1046528 (1022.00 MiB 1071.64 MB) Used Dev Size : 1046528 (1022.00 MiB 1071.64 MB) Raid Devices : 2 Total Devices : 3 Persistence : Superblock is persistent Update Time : Tue Jul 23 19:25:59 2019 State : clean Active Devices : 2 Working Devices : 3 Failed Devices : 0 Spare Devices : 1 Consistency Policy : resync Name : linux-node2-202:0 (local to host linux-node2-202) UUID : 15c85ba6:1df98782:c64f8908:3eee284d Events : 17 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 模拟sdb1故障 [root@linux-node2-202 ~]# mdadm /dev/md0 -f /dev/sdb1 mdadm: set /dev/sdb1 faulty in /dev/md0 [root@linux-node2-202 ~]# mdadm -D /dev/md0 /dev/md0: Version : 1.2 Creation Time : Tue Jul 23 19:25:54 2019 Raid Level : raid1 Array Size : 1046528 (1022.00 MiB 1071.64 MB) Used Dev Size : 1046528 (1022.00 MiB 1071.64 MB) Raid Devices : 2 Total Devices : 3 Persistence : Superblock is persistent Update Time : Tue Jul 23 19:27:52 2019 State : clean Active Devices : 2 Working Devices : 2 Failed Devices : 1 Spare Devices : 0 Consistency Policy : resync Name : linux-node2-202:0 (local to host linux-node2-202) UUID : 15c85ba6:1df98782:c64f8908:3eee284d Events : 36 Number Major Minor RaidDevice State 2 8 19 0 active sync /dev/sdb3 1 8 18 1 active sync /dev/sdb2 0 8 17 - faulty /dev/sdb1 将sdb1从raid1中删除 [root@linux-node2-202 ~]# mdadm /dev/md0 -r /dev/sdb1 mdadm: hot removed /dev/sdb1 from /dev/md0 [root@linux-node2-202 ~]# mdadm -D /dev/md0 /dev/md0: Version : 1.2 Creation Time : Tue Jul 23 19:25:54 2019 Raid Level : raid1 Array Size : 1046528 (1022.00 MiB 1071.64 MB) Used Dev Size : 1046528 (1022.00 MiB 1071.64 MB) Raid Devices : 2 Total Devices : 2 Persistence : Superblock is persistent Update Time : Tue Jul 23 19:28:30 2019 State : clean Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 Consistency Policy : resync Name : linux-node2-202:0 (local to host linux-node2-202) UUID : 15c85ba6:1df98782:c64f8908:3eee284d Events : 37 Number Major Minor RaidDevice State 2 8 19 0 active sync /dev/sdb3 1 8 18 1 active sync /dev/sdb2 将sdb1添加回raid1 [root@linux-node2-202 ~]# mdadm /dev/md0 -a /dev/sdb1 mdadm: added /dev/sdb1 [root@linux-node2-202 ~]# mdadm -D /dev/md0 /dev/md0: Version : 1.2 Creation Time : Tue Jul 23 19:25:54 2019 Raid Level : raid1 Array Size : 1046528 (1022.00 MiB 1071.64 MB) Used Dev Size : 1046528 (1022.00 MiB 1071.64 MB) Raid Devices : 2 Total Devices : 3 Persistence : Superblock is persistent Update Time : Tue Jul 23 19:28:41 2019 State : clean Active Devices : 2 Working Devices : 3 Failed Devices : 0 Spare Devices : 1 Consistency Policy : resync Name : linux-node2-202:0 (local to host linux-node2-202) UUID : 15c85ba6:1df98782:c64f8908:3eee284d Events : 38 Number Major Minor RaidDevice State 2 8 19 0 active sync /dev/sdb3 1 8 18 1 active sync /dev/sdb2 3 8 17 - spare /dev/sdb1
3、简述TCP链接建立和断开过程
https://www.cnblogs.com/bj-mr-li/p/11106397.html
https://www.cnblogs.com/bj-mr-li/p/11106390.html
TCP建立连接的过程叫三次握手 三次握手 第一次，客户端发起SYN=1,seq=x,给服务端,并将状态为SYN-SEND 第二次，服务端收到第一次请求，回应SYN=1,ACK=1,seq=x,状态为SYN-RECV 第三次，客户端收到服务端的回包，回应ACK=1,seq=x+1 seq=y+1,状态为ESTAB 客户端收到回包后连接建立，开始发送数据 TCP断开连接的过程叫四次挥手，比三次握手多了一个确认过程 第一次，客户端发送FIN=1,seq=x给服务端，状态由ESTAB修改为FIN-WAIT1 第二次，服务端收到后，回应ACK=1, seq=y,ack=x+1，状态为CLOSE-WAIT，通知进程关闭连接，客户端状态为FIN-WAIT2 第三次，服务端收完所有数据后，发送FIN=1,ACK=1,seq=z,ack=x+1,状态为LAST-ACK 第四次，客户端收到后，等待2MSL(2倍传送时间)后，发送ACK=1,seq=x+1,ack=z+1,连接关闭
4、简述TCP和UDP的区别
1：TCP基于连接，UDP基于无连接。 2：TCP对系统资源要求高，UDP少。 3：TCP是基于字节流的，UDP是数据报文模式。 4：TCP复杂，UDP简单。 5：TCP有验证过程，是可靠的连接，UDP无验证过程，是不可靠的连接