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应用场景和已知存在的问题：
适用于CentOS6或CentOS7（可能适用于CentOS4或5等早些版本）
根文件系统（被扩展的文件系统）采用LVM进行管理，例如mount命令输出“/dev/mapper/vg_$hostname-lv_root on / type ext4 (rw)”中含有“mapper”关键词
自动扩容根文件系统，如果想扩展其他文件系统，例如有的业务应用数据目录不在根分区中，则需要修改Shell脚本代码中的VG_PATH_TO_EXTEND变量（约78行）。
仅支持ext2、ext3、ext4、xfs等分区格式的文件系统
可能不支持某些过多自定义的CentOS系统，但核心步骤相似
脚本中仅添加了scsi磁盘支持，如需要管理其他磁盘，则需要自己扩充脚本
为了简化脚本，避免执行多次（本程序没有写执行锁），先前已经存在的磁盘名已经设定为sda，见Shell脚本代码中第45行的ONLINE_SCSI_DISK_PRESENT变量
考虑点：
由于CentOS6和CentOS7在默认根文件系统的文件系统格式存在差异，需要判断是否为xfs，如果是xfs则应该使用xfs_growfs而不是一味的使用resize2fs。
使用resize2fs扩展ext2、ext3、ext4格式的文件系统，使用xfs_growfs扩展xfs格式的文件系统
同一脚本在同一系统多次被执行可能引发的错误，可以考虑使用文件锁来解决这个问题
编程思路：
（之前应该准备或检查Shell脚本运行环境）获取当前使用中的块设备文件名
获取新添加scsi磁盘的文件名
获取LVM卷组名（vg）、将被扩展的卷组名的文件路径
将新添加磁盘使用fdisk创建分区并格式化为LVM格式
创建物理卷，pvcreate
扩展卷组，vgextend
调节逻辑卷大小，lvresize
判断是否是xfs文件系统
同步文件系统，使得扩容生效
返回系统磁盘使用情况
Shell代码：
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 | #!/bin/bash # Usage: Automatic expand lv with LVM managed disk # Setp 1: Add Hard Disk or Storage to Computing unit # Setp 2: Execute this script with root privilege # Setp 3: Mind info of this script execution result # Open the refrigerator door, get the shell script execution environment ready # Put the elephant into the refrigerator, how the shell scripts works # Close the refrigerator door, check out the result of execution # Simetimes, we have to pull new elephant or elephant dung out here, unset variables of shell script function check_execution_result(){ if [[ ! -z $RETVAL ]]; then unset RETVAL fi RETVAL=$? if [[ $RETVAL - ne 0 ]]; then echo execution failed! exit $RETVAL else echo execution successfully! fi unset RETVAL } # lsblk --scsi # lsblk --all # NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT # fd0 2:0 1 4K 0 disk # sda 8:0 0 40G 0 disk # ├─sda1 8:1 0 500M 0 part /boot # └─sda2 8:2 0 39.5G 0 part # ├─centos-swap 253:0 0 3.9G 0 lvm [SWAP] # └─centos-root 253:1 0 35.6G 0 lvm / # sdb 8:16 0 16G 0 disk # sr0 11:0 1 6.6G 0 rom # Show present scsi disk online # Q: Why use "xargs" here? # A: Convert the text from multi-line single-column into single-line multi-column, for sed operation ONLINE_SCSI_DISK_PRESENT=$(lsblk --all | grep disk | grep - v fd | awk '{print $1}' | xargs ) # TODO # For execution this script beyond twice ONLINE_SCSI_DISK_PRESENT=sda # Find new scsi disk online # TODO figure it out why there is host0? echo "- - -" > /sys/class/scsi_host/host0/scan echo "- - -" > /sys/class/scsi_host/host1/scan echo "- - -" > /sys/class/scsi_host/host2/scan # Show new added scsi disk online ONLINE_SCSI_DISK_NEWADD=$(lsblk --all | grep disk | grep - v fd | awk '{print $1}' | xargs echo | sed "s/$ONLINE_SCSI_DISK_PRESENT//g" ) # Construct disk file with full path echo New Added SCSI Disk: $ONLINE_SCSI_DISK_NEWADD # Get VG Name VG_Name=$(vgdisplay | grep 'VG Name' | awk '{print $NF}' ) VG_PATH_TO_EXTEND=$(lvdisplay | grep 'LV Path' | awk '{print $NF}' | grep root) for BLOCK in $ONLINE_SCSI_DISK_NEWADD; do ONLINE_SCSI_DISK_NEWADD_FILENAME= "/dev/" $BLOCK # end-of-file contents and eof mark must start row1 fdisk $ONLINE_SCSI_DISK_NEWADD_FILENAME > /dev/null 2>&1<<eof n p 1 t 8e w eof check_execution_result LVM_OPERATION_DISK_FILENAME=$ONLINE_SCSI_DISK_NEWADD_FILENAME "1" pvcreate $LVM_OPERATION_DISK_FILENAME > /dev/null 2>&1 check_execution_result vgextend $VG_Name $LVM_OPERATION_DISK_FILENAME > /dev/null 2>&1 check_execution_result lvresize -l +100%FREE $VG_PATH_TO_EXTEND > /dev/null 2>&1 check_execution_result # resize2fs - ext2/ext3/ext4 file system resizer # xfs_growfs, xfs_info - expand an XFS filesystem #[root@hlc7172009 ~]# resize2fs /dev/mapper/centos-root #resize2fs 1.42.9 (28-Dec-2013) #resize2fs: Bad magic number in super-block while trying to open /dev/mapper/centos-root #Couldn't find valid filesystem superblock. #[root@hlc7172009 ~]# #[root@hlc7172009 ~]# xfs_growfs $VG_PATH_TO_EXTEND #meta-data=/dev/mapper/centos-root isize=256 agcount=4, agsize=2334208 blks # = sectsz=512 attr=2, projid32bit=1 # = crc=0 #data = bsize=4096 blocks=9336832, imaxpct=25 # = sunit=0 swidth=0 blks #naming =version 2 bsize=4096 ascii-ci=0 ftype=0 #log =internal bsize=4096 blocks=4559, version=2 # = sectsz=512 sunit=0 blks, lazy-count=1 #realtime =none extsz=4096 blocks=0, rtextents=0 #data blocks changed from 9336832 to 13530112 #[root@hlc7172009 ~]# # Check xfs_info if is installed which xfs_info > /dev/null 2>&1 if [[ $? - ne 0 ]]; then yum install xfsprogs -y > /dev/null 2>&1 fi # end Check xfs_info if is installed # Check VG_PATH_TO_EXTEND if is xfs filesystem xfs_info $VG_PATH_TO_EXTEND > /dev/null 2>&1 if [[ $? - ne 0 ]]; then # is not xfs VG_PATH_TO_EXTEND_IS_NOT_XFS=0 else # is xfs VG_PATH_TO_EXTEND_IS_NOT_XFS=1 fi # end Check VG_PATH_TO_EXTEND if is xfs filesystem # TODO CentOS7 default filesystem is xfs, so we can check it out by OS if is CentOS7 if [[ $VG_PATH_TO_EXTEND_IS_NOT_XFS ]]; then # is xfs xfs_growfs $VG_PATH_TO_EXTEND > /dev/null 2>&1 else # is not xfs resize2fs $VG_PATH_TO_EXTEND > /dev/null 2>&1 fi check_execution_result df -h lsblk --all done |
测试结果：
（1）添加磁盘前：
（2）添加磁盘并执行脚本后：
由此可见根分区已经由原先的36GB变为52GB，表示LVM扩容成功。
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本文转自 urey_pp 51CTO博客，原文链接：http://blog.51cto.com/dgd2010/1619692，如需转载请自行联系原作者