基础知识 -- Linux 逻辑卷管理技术2
sunln00 2011-04-01
怎样从VG中移走PV ?
https://svn.wso2.org//repos//wso2//tags//wsas//java//3.2.1//
例如将/dev/sdb1从逻辑卷中移出:
linux-0eob:/#pvmove/dev/sdb1
/dev/sdb1: Moved: 100.0%linux-0eob:/ # pvscan
PV/dev/sdb1VGvg0lvm2[52.00MB/52.00MBfree]
PV/dev/sdb2VGvg0lvm2[52.00MB/32.00MBfree]
PV/dev/sdb3VGvg0lvm2[52.00MB/52.00MBfree]
Total:3[156.00MB]/inuse:3[156.00MB]/innoVG:0[0]
从vg0中移走pv
linux-0eob:/ # vgreduce vg0 /dev/sdb1Removed "/dev/sdb1" from volume group "vg0"
再一次查看:
linux-0eob:/#pvscan
PV/dev/sdb2VGvg0lvm2[52.00MB/32.00MBfree]
PV/dev/sdb3VGvg0lvm2[52.00MB/52.00MBfree]
PV/dev/sdb1lvm2[54.88MB]
Total:3[158.88MB]/inuse:2[104.00MB]/innoVG:1[54.88MB]
这样/dev/sdb1就变成自由分区了怎样指定vg中逻辑块的大小 ?
我们可以使用vgcreate的-s选项指定逻辑块大小,这样可以支持更大的逻辑卷
linux-0eob:/#vgcreatevg1-s8M/dev/sdb1
Volumegroup"vg1"successfullycreated
linux-0eob:/#vgdisplayvg1
---Volumegroup---
VGNamevg1
SystemID
Formatlvm2
MetadataAreas1
MetadataSequenceNo1
VGAccessread/write
VGStatusresizable
MAXLV0
CurLV0
OpenLV0
MaxPV0
CurPV1
ActPV1
VGSize48.00MB
PESize8.00MB
TotalPE6
AllocPE/Size0/0
FreePE/Size6/48.00MB
VG UUID UWko2s-q9Qp-ybSZ-ZHJr-1FHl-R60q-8jzaR5在vg1上创建逻辑卷
linux-0eob:/#lvcreate-nlvdata2-l2vg1
Logicalvolume"lvdata2"created
linux-0eob:/#lvdisplay
---Logicalvolume---
LVName/dev/vg0/lvdata
VGNamevg0
LVUUIDtYWFX0-Msor-q6I3-dZjE-W06M-UKyj-McRdpP
LVWriteAccessread/write
LVStatusavailable
#open1
LVSize20.00MB
CurrentLE5
Segments1
Allocationinherit
Readaheadsectorsauto
-currentlysetto256
Blockdevice253:0
---Logicalvolume---
LVName/dev/vg1/lvdata2
VGNamevg1
LVUUIDU2y1YP-uHOb-dKh3-pZTP-LFXJ-mOUm-hFZKzZ
LVWriteAccessread/write
LVStatusavailable
#open0
LVSize16.00MB
CurrentLE2
Segments1
Allocationinherit
Readaheadsectorsauto
-currentlysetto256
Blockdevice253:1
lvcreate 强大的功能还有哪些 ?-s 选项可以备份lv中的数据,--snapshots;可以实时捕捉数据的变化.
但是这种方式只能在负载不高的情形下进行.
linux-0eob:/#lvcreate-nsnap-s-l4/dev/vg1/lvdata2
Logicalvolume"snap"created
这样/dev/vg1/lvdata2 中的内容会与 /dev/vg1/snap下的数据是实时同步的如何转换逻辑卷的状态 ?
linux-0eob:/#lvscan
ACTIVE'/dev/vg0/lvdata'[20.00MB]inherit
ACTIVEOriginal'/dev/vg1/lvdata2'[16.00MB]inherit
ACTIVESnapshot'/dev/vg1/snap'[32.00MB]inherit
linux-0eob:/#vgchange-anvg0
Can'tdeactivatevolumegroup"vg0"with1openlogicalvolume(s)
linux-0eob:/#vgchange-anvg1
0logicalvolume(s)involumegroup"vg1"nowactive
linux-0eob:/#lvscan
ACTIVE'/dev/vg0/lvdata'[20.00MB]inherit
inactiveOriginal'/dev/vg1/lvdata2'[16.00MB]inherit
inactive Snapshot '/dev/vg1/snap' [32.00 MB] inheritlinux-0eob:/ # vgchange -ay vg1
1logicalvolume(s)involumegroup"vg1"nowactive
linux-0eob:/#lvscan
ACTIVE'/dev/vg0/lvdata'[20.00MB]inherit
ACTIVEOriginal'/dev/vg1/lvdata2'[16.00MB]inherit
ACTIVE Snapshot '/dev/vg1/snap' [32.00 MB] inherit