Linux LVM创建及扩展和减小
LVM逻辑卷 1、 LVM逻辑卷机制 LVM逻辑卷(Logical volumes manager)是将多个分区或者物理硬盘从逻辑上作为一个整体,从这个整体上划分出不同的逻辑分区;逻辑分区可以根据需要进行扩大和缩小 整个创建逻辑分区过程依次创建pv、vg、lv; pv为分区或者物理硬盘,又PE为基本单元组成; vg 为一个或多个pv组成的整体 lv为从vg卷组中分割出分区,该分区可以格式化建立文件系统; 2、 LVM创建及管理 由于Linux支持LVM机制,那么就离不开LVM的创建和管理,LVM管理工具包括了pv、vg、lv、的扫描、创建、删除、扩展、显示、减小、以及PE大小的设置; 功能 PV VG LV 扫描 pvscan vgscan lvscan 创建 pvcreate vgcreate lvcreate 显示 pvdisplay vgdisplay lvdisplay 删除 pvremove vgremove lvremove 扩展 -- vgextend lvextend 减少 -- vgreduce lvreduce 常用语法: pvcreate 物理卷或分区名 vgcreate –s pe大小 卷组名 物理卷 lvcreate -L lv大小 –n lv名 vg名 lvcreate -l pe个数 –n lv名 vg名 lvextend –L +大小 lv逻辑分区 lvreduce resize2fs lv分区大小 注意事项:如果不是单个硬盘而是多个分区构建pv,一定要将分区化为8e格式; 3、 实例 现在有4个50G的硬盘,将sab、sdc、sdd作成一个vg,然后分三个40G的ext4分区,在创建一个250M的swap分区; 3.1、创建物理卷 [root@woon ~]# pvcreate /dev/sdb /dev/sdc /dev/sdd Physical volume "/dev/sdb" successfully created Physical volume "/dev/sdc" successfully created Physical volume "/dev/sdd" successfully created [root@woon ~]# 查看pv [root@woon ~]# pvdisplay --- Physical volume --- "/dev/sdb" is a new physical volume of "50.00 GiB" --- NEW Physical volume --- PV Name /dev/sdb VG Name PV Size 50.00 GiB Allocatable NO PE Size 0 Total PE 0 Free PE 0 Allocated PE 0 PV UUID t6XA0f-nAxl-0I8f-XGj0-eojd-PBr0-NnAUuU "/dev/sdc" is a new physical volume of "50.00 GiB" --- NEW Physical volume --- PV Name /dev/sdc VG Name PV Size 50.00 GiB Allocatable NO PE Size 0 Total PE 0 Free PE 0 Allocated PE 0 PV UUID AKREKZ-L5rt-UdZR-4iy6-Z2BH-vwI0-qEXqZa "/dev/sdd" is a new physical volume of "50.00 GiB" --- NEW Physical volume --- PV Name /dev/sdd VG Name PV Size 50.00 GiB Allocatable NO PE Size 0 Total PE 0 Free PE 0 Allocated PE 0 PV UUID vyHztS-vM5b-j40c-mHE9-9A3r-wU7b-tbggy3 3.2、创建卷组并查看 [root@woon ~]# vgcreate woonvg /dev/sdb /dev/sdc /dev/sdd Volume group "woonvg" successfully created VG Name woonvg System ID Format lvm2 Metadata Areas 3 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 3 Act PV 3 VG Size 149.99 GiB PE Size 4.00 MiB Total PE 38397 Alloc PE / Size 0 / 0 Free PE / Size 38397 / 149.99 GiB VG UUID tGmw2t-5iL0-FuEV-UmqP-RtsT-oOTc-O4aLNa; 默认PE大小4M 3.3、创建LV并查看绿分区 [root@woon ~]# lvcreate -L 40G -n woon_lv1 woonvg Logical volume "woon_lv1" created [root@woon ~]# lvcreate -l 10240 -n woon_lv2 woonvg Logical volume "woon_lv2" created [root@woon ~]# lvcreate -l 10240 -n woon_lv3 woonvg Logical volume "woon_lv3" created [root@woon ~]# lvdisplay --- Logical volume --- LV Path /dev/woonvg/woon_lv1 LV Name woon_lv1 VG Name woonvg LV UUID zeOmDa-TAp0-oenx-YMi6-kYUa-IJpR-IWDzGD LV Write Access read/write LV Creation host, time woon, 2015-02-09 23:03:20 +0800 LV Status available # open 0 LV Size 40.00 GiB Current LE 10240 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 253:2 --- Logical volume --- LV Path /dev/woonvg/woon_lv2 LV Name woon_lv2 VG Name woonvg LV UUID 10UXVD-2efM-GzuO-fQ2z-0guQ-1EW2-G3Hls7 LV Write Access read/write LV Creation host, time woon, 2015-02-09 23:04:32 +0800 LV Status available # open 0 LV Size 40.00 GiB Current LE 10240 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 253:3 --- Logical volume --- LV Path /dev/woonvg/woon_lv3 LV Name woon_lv3 VG Name woonvg LV UUID DaHx1r-6hQe-w8kg-8PXR-zZeq-0lcP-uLOnPc LV Write Access read/write LV Creation host, time woon, 2015-02-09 23:04:40 +0800 LV Status available # open 0 LV Size 40.00 GiB Current LE 10240 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 253:4 3.4、格式化lv逻辑卷 [root@woon ~]# mkfs.ext4 /dev/woonvg/woon_lv1 [root@woon ~]# mkfs.ext4 /dev/woonvg/woon_lv2 [root@woon ~]# mkfs.ext4 /dev/woonvg/woon_lv3 3.4.1、格式化后挂载到/opt/woon_lv1、woon_lv2、woon_lv3下 [root@woon ~]# mount /dev/woonvg/woon_lv1 /opt/woon_lv1 [root@woon ~]# mount /dev/woonvg/woon_lv2 /opt/woon_lv2 [root@woon ~]# mount /dev/woonvg/woon_lv3 /opt/woon_lv3 3.4.2、 查看挂载情况 [root@woon woon_lv1]# mount | tail -n 3 /dev/mapper/woonvg-woon_lv1 on /opt/woon_lv1 type ext4 (rw) /dev/mapper/woonvg-woon_lv2 on /opt/woon_lv2 type ext4 (rw) /dev/mapper/woonvg-woon_lv3 on /opt/woon_lv3 type ext4 (rw) [root@woon woon_lv1]# 3.4.3、分一个250M的swap分区并挂载 [root@woon woon_lv1]# lvcreate -L 250M -n woon_swap woonvg Rounding up size to full physical extent 252.00 MiB Logical volume "woon_swap" created 此时发现明明分的是250M,但是执行命令后确实252M,经过排查是由于PE大小影响的,由于PE是PV的基本单位,导致250M不能精确划分;在目前的环境以下如果想要实现就必须删除所有的lv、vg,调整PE大小为1M即可;想要解决这个问题只需要在创建vg时使用以下命令: vgcreate –s 1M woonvg /dev/sd[b-d] 4、调整分区大小 4.1、扩展分区 将woon_lv1扩展到50G [root@woon woon_lv1]# lvextend -L 50G /dev/woonvg/woon_lv1 Size of logical volume woonvg/woon_lv1 changed from 40.00 GiB (10240 extents) to 50.00 GiB (12800 extents). Logical volume woon_lv1 successfully resized 此时分区扩展到50G了,但是内核并不是知道,所以要通知内核永达resize2fs指令 [root@woon woon_lv1]# resize2fs /dev/woonvg/woon_lv1 [root@woon woon_lv1]# df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/vg_woon-lv_root 8.3G 4.0G 4.0G 51% / tmpfs 504M 224K 503M 1% /dev/shm /dev/sda1 477M 27M 426M 6% /boot /dev/sdf1 100G 13G 88G 13% /opt/ntfs1 /dev/sde1 459G 70M 435G 1% /opt/gpt1 /dev/sr0 3.8G 3.8G 0 100% /media/CentOS_6.6_Final /dev/mapper/woonvg-woon_lv1 50G 52M 47G 1% /opt/woon_lv1 /dev/mapper/woonvg-woon_lv2 40G 48M 38G 1% /opt/woon_lv2 /dev/mapper/woonvg-woon_lv3 40G 48M 38G 1% /opt/woon_lv3 4.2、减小一个分区 分区的减小是不能在线直接减小的,应该先卸载分区,然后减小文件系统,然后减小分区大小,最后重新挂载;如将woon_lv2减小到30G ,不损坏文件系统; [root@woon woon_lv1]# umount /dev/woonvg/woon_lv2 [root@woon woon_lv1]# e2fsck -f /dev/woonvg/woon_lv2 [root@woon woon_lv1]# resize2fs /dev/woonvg/woon_lv2 30G [root@woon woon_lv1]# lvreduce -L 30G /dev/woonvg/woon_lv2 WARNING: Reducing active logical volume to 30.00 GiB THIS MAY DESTROY YOUR DATA (filesystem etc.) Do you really want to reduce woon_lv2? [y/n]: y Size of logical volume woonvg/woon_lv2 changed from 40.00 GiB (10240 extents) to 30.00 GiB (7680 extents). Logical volume woon_lv2 successfully resized [root@woon woon_lv1]# mount /dev/woonvg/woon_lv2 /opt/woon_lv2 [root@woon woon_lv1]# df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/vg_woon-lv_root 8.3G 4.0G 4.0G 51% / tmpfs 504M 224K 503M 1% /dev/shm /dev/sda1 477M 27M 426M 6% /boot /dev/sdf1 100G 13G 88G 13% /opt/ntfs1 /dev/sde1 459G 70M 435G 1% /opt/gpt1 /dev/sr0 3.8G 3.8G 0 100% /media/CentOS_6.6_Final /dev/mapper/woonvg-woon_lv1 50G 52M 47G 1% /opt/woon_lv1 /dev/mapper/woonvg-woon_lv3 40G 48M 38G 1% /opt/woon_lv3 /dev/mapper/woonvg-woon_lv2 30G 44M 28G 1% /opt/woon_lv2
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