pv物理卷
情況介紹：
一、由於硬碟或者分區的操作方式其實都一樣，所以我這里就以分區為例。
二、/home分區2.6G，由如下pv組成：
/dev/sda5 100M
/dev/sda6 200M
/dev/sda7 300M
/dev/sda8 400M
/dev/sda9 500M
/dev/sda10 600M
/dev/sda11 500M
很碎對吧?^_^因為測試。
三、隨機寫了一堆文件進去，用量達到了2G，空閑500M
四、准備將sda6這個200M的PV卸掉(卸掉的容量必須小於空閑容量)
好了開始具體操作了。
卸載分區(縮小操作必須卸載才能進行)：
umount /home
縮小分區：
e2fsck -f /dev/liuhg_disk/home
resize2fs /dev/liuhg_disk/home 2200M
首先將分區縮小到2200M這是為了給sda6騰出空間，sda6為200M，而我騰出了400M，因此應該是足夠的。
縮小邏輯卷：
lvrece -L 2200M /dev/liuhg_disk/home
分區縮小了用到的邏輯卷也要隨著縮小，並查看PV使用的狀態：
pvdisplay -m
顯示如下：
--- Physical volume ---
PV Name /dev/sda5
VG Name liuhg_disk
PV Size 103.26 MiB / not usable 3.26 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 25
Free PE 0
Allocated PE 25
PV UUID 5lnx52-b4jc-OOfZ-f2QA-ttdQ-DZeD-Ce3rb3
--- Physical Segments ---
Physical extent 0 to 24:
Logical volume /dev/liuhg_disk/home
Logical extents 0 to 24
--- Physical volume ---
PV Name /dev/sda6
VG Name liuhg_disk
PV Size 203.92 MiB / not usable 3.92 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 50
Free PE 0 <-----太悲劇了，sda6里寫滿了數據一點不剩
Allocated PE 50 <-----這50PE的數據要挪走才行，否則數據就丟了，並且存放的地方也必須是連續的至少50PE
PV UUID S2ane6-nlFG-uSNR-35NP-Yxa6-cXRb-r8E8mK
--- Physical Segments ---
Physical extent 0 to 49:
Logical volume /dev/liuhg_disk/home
Logical extents 25 to 74
--- Physical volume ---
PV Name /dev/sda7
VG Name liuhg_disk
PV Size 305.89 MiB / not usable 1.89 MiB
Allocatable yes
PE Size 4.00 MiB
Total PE 76
Free PE 76 <---這個分區有76個空餘，因此預計裝那50個是不會有問題的
Allocated PE 0
PV UUID 9CFnlx-CAEw-CSul-Rig9-FiCN-zK0a-oGmTEP
--- Physical Segments ---
Physical extent 0 to 75:
FREE
--- Physical volume ---
PV Name /dev/sda8
VG Name liuhg_disk
PV Size 407.87 MiB / not usable 3.87 MiB
Allocatable yes
PE Size 4.00 MiB
Total PE 101
Free PE 60
Allocated PE 41
PV UUID X0I8p0-x2xr-2xLG-QQD4-jbtS-3C4i-xPn4Bl
--- Physical Segments ---
Physical extent 0 to 40:
Logical volume /dev/liuhg_disk/home
Logical extents 471 to 511
Physical extent 41 to 100:
FREE
--- Physical volume ---
PV Name /dev/sda9
VG Name liuhg_disk
PV Size 509.84 MiB / not usable 1.84 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 127
Free PE 0
Allocated PE 127
PV UUID avJQaA-oMKt-NEoJ-ojBK-2Csc-1dca-1mh6Ue
--- Physical Segments ---
Physical extent 0 to 126:
Logical volume /dev/liuhg_disk/home
Logical extents 225 to 351
--- Physical volume ---
PV Name /dev/sda10
VG Name liuhg_disk
PV Size 603.98 MiB / not usable 3.98 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 150
Free PE 0
Allocated PE 150
PV UUID JlMIAF-A49n-M6HA-ZLXf-d8nS-pfZr-YeQsKT
--- Physical Segments ---
Physical extent 0 to 149:
Logical volume /dev/liuhg_disk/home
Logical extents 75 to 224
--- Physical volume ---
PV Name /dev/sda11
VG Name liuhg_disk
PV Size 478.47 MiB / not usable 2.47 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 119
Free PE 0
Allocated PE 119
PV UUID xnHJNA-tDVx-dryX-KM1x-g96Y-sptI-9iUOcU
--- Physical Segments ---
Physical extent 0 to 118:
Logical volume /dev/liuhg_disk/home
Logical extents 352 to 470
將sda6設置為離線狀態：
pvchange -xn /dev/sda6
使用pvdisplay -m
顯示如下：
……
--- Physical volume ---
PV Name /dev/sda6
VG Name liuhg_disk
PV Size 203.92 MiB / not usable 3.92 MiB
Allocatable NO <-----表示已經關閉了該PV
PE Size 4.00 MiB
Total PE 50
Free PE 0
Allocated PE 50
PV UUID S2ane6-nlFG-uSNR-35NP-Yxa6-cXRb-r8E8mK
……
將sda6的數據移走：
pvmove -i 1 /dev/sda6
-i 1是每1秒鍾報告一次數據遷移的進度。
[root@liuhg /]# pvmove -i 1 /dev/sda6
/dev/sda6: Moved: 38.0%
/dev/sda6: Moved: 84.0%
/dev/sda6: Moved: 100.0%
重新用pvdisplay -m
顯示如下：
……
--- Physical volume ---
PV Name /dev/sda6
VG Name liuhg_disk
PV Size 203.92 MiB / not usable 3.92 MiB
Allocatable NO
PE Size 4.00 MiB
Total PE 50
Free PE 50 <----顯示完全空閑和Total PE數一致
Allocated PE 0
PV UUID S2ane6-nlFG-uSNR-35NP-Yxa6-cXRb-r8E8mK
……
從卷組里把sda6刪除:
[root@liuhg /]# vgrece liuhg_disk /dev/sda6
Removed "/dev/sda6" from volume group "liuhg_disk"
pvdisplay -m再看看吧：
--- NEW Physical volume --- <-----還告訴你這是一個新的PV ^_^
PV Name /dev/sda6
VG Name <-----空了
PV Size 203.92 MiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID S2ane6-nlFG-uSNR-35NP-Yxa6-cXRb-r8E8mK
到此vgdisplay -v能看到已經沒有了/dev/sda6了。重新掛載/home
[root@liuhg /]# mount /dev/liuhg_disk/home /home
[root@liuhg /]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 2.0G 546M 1.3G 30% /
tmpfs 504M 0 504M 0% /dev/shm
/dev/mapper/liuhg_disk-home
2.2G 1.8G 42M 98% /home
進去看看數據，一個都沒丟。
『貳』 如何安全的刪除Linux LVM中的PV物理卷
情況介紹：
一、由於硬碟或者分區的操作方式其實都一樣，所以我這里就以分區為例。
二、/home分區2.6G，由如下pv組成：
/dev/sda5 100M
/dev/sda6 200M
/dev/sda7 300M
/dev/sda8 400M
/dev/sda9 500M
/dev/sda10 600M
/dev/sda11 500M
很碎對吧?^_^因為測試。
三、隨機寫了一堆文件進去，用量達到了2G，空閑500M
四、准備將sda6這個200M的PV卸掉(卸掉的容量必須小於空閑容量)
好了開始具體操作了。
卸載分區(縮小操作必須卸載才能進行)：
『叄』 LVM問題：請問pv為什麼只有pvcreate，沒有pvextend命令謝謝！
pv，就是物理卷，是將物理硬碟分區作為物理卷,物理分區是不能擴展的。
你多創建幾個pv,就等於擴展了。
『肆』 PV LV 分別是什麼
Physical volume（PV，物理卷）
多磁碟PV組成存儲池VG，再根據應用細分邏輯卷LV，空間利用率提高
LVM———Logical Volume Manager(邏輯卷管理管理管理管理器)的簡寫
『伍』 如何安全的刪除Linux LVM中的PV物理卷
一、由於硬碟或者分區的操作方式其實都一樣，所以就以分區為例。
二、/home分區2.6G，由如下pv組成：
/dev/sda5 100M
/dev/sda6 200M
/dev/sda7 300M
/dev/sda8 400M
/dev/sda9 500M
/dev/sda10 600M
/dev/sda11 500M
很碎對吧?^_^因為測試。
三、隨機寫了一堆文件進去，用量達到了2G，空閑500M
四、准備將sda6這個200M的PV卸掉(卸掉的容量必須小於空閑容量)
好了開始具體操作了。
卸載分區(縮小操作必須卸載才能進行)：
umount /home
縮小分區：
e2fsck -f /dev/liuhg_disk/home
resize2fs /dev/liuhg_disk/home 2200M
首先將分區縮小到2200M這是為了給sda6騰出空間，sda6為200M，而我騰出了400M，因此應該是足夠的。
縮小邏輯卷：
lvrece -L 2200M /dev/liuhg_disk/home
分區縮小了用到的邏輯卷也要隨著縮小，並查看PV使用的狀態：
pvdisplay -m
顯示如下：
--- Physical volume ---
PV Name /dev/sda5
VG Name liuhg_disk
PV Size 103.26 MiB / not usable 3.26 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 25
Free PE 0
Allocated PE 25
PV UUID 5lnx52-b4jc-OOfZ-f2QA-ttdQ-DZeD-Ce3rb3
--- Physical Segments ---
Physical extent 0 to 24:
Logical volume /dev/liuhg_disk/home
Logical extents 0 to 24
--- Physical volume ---
PV Name /dev/sda6
VG Name liuhg_disk
PV Size 203.92 MiB / not usable 3.92 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 50
Free PE 0 <-----太悲劇了，sda6里寫滿了數據一點不剩
Allocated PE 50 <-----這50PE的數據要挪走才行，否則數據就丟了，並且存放的地方也必須是連續的至少50PE
PV UUID S2ane6-nlFG-uSNR-35NP-Yxa6-cXRb-r8E8mK
--- Physical Segments ---
Physical extent 0 to 49:
Logical volume /dev/liuhg_disk/home
Logical extents 25 to 74
--- Physical volume ---
PV Name /dev/sda7
VG Name liuhg_disk
PV Size 305.89 MiB / not usable 1.89 MiB
Allocatable yes
PE Size 4.00 MiB
Total PE 76
Free PE 76 <---這個分區有76個空餘，因此預計裝那50個是不會有問題的
Allocated PE 0
PV UUID 9CFnlx-CAEw-CSul-Rig9-FiCN-zK0a-oGmTEP
--- Physical Segments ---
Physical extent 0 to 75:
FREE
--- Physical volume ---
PV Name /dev/sda8
VG Name liuhg_disk
PV Size 407.87 MiB / not usable 3.87 MiB
Allocatable yes
PE Size 4.00 MiB
Total PE 101
Free PE 60
Allocated PE 41
PV UUID X0I8p0-x2xr-2xLG-QQD4-jbtS-3C4i-xPn4Bl
--- Physical Segments ---
Physical extent 0 to 40:
Logical volume /dev/liuhg_disk/home
Logical extents 471 to 511
Physical extent 41 to 100:
FREE
--- Physical volume ---
PV Name /dev/sda9
VG Name liuhg_disk
PV Size 509.84 MiB / not usable 1.84 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 127
Free PE 0
Allocated PE 127
PV UUID avJQaA-oMKt-NEoJ-ojBK-2Csc-1dca-1mh6Ue
--- Physical Segments ---
Physical extent 0 to 126:
Logical volume /dev/liuhg_disk/home
Logical extents 225 to 351
--- Physical volume ---
PV Name /dev/sda10
VG Name liuhg_disk
PV Size 603.98 MiB / not usable 3.98 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 150
Free PE 0
Allocated PE 150
PV UUID JlMIAF-A49n-M6HA-ZLXf-d8nS-pfZr-YeQsKT
--- Physical Segments ---
Physical extent 0 to 149:
Logical volume /dev/liuhg_disk/home
Logical extents 75 to 224
--- Physical volume ---
PV Name /dev/sda11
VG Name liuhg_disk
PV Size 478.47 MiB / not usable 2.47 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 119
Free PE 0
Allocated PE 119
PV UUID xnHJNA-tDVx-dryX-KM1x-g96Y-sptI-9iUOcU
--- Physical Segments ---
Physical extent 0 to 118:
Logical volume /dev/liuhg_disk/home
Logical extents 352 to 470
將sda6設置為離線狀態：
pvchange -xn /dev/sda6
使用pvdisplay -m
顯示如下：
……
--- Physical volume ---
PV Name /dev/sda6
VG Name liuhg_disk
PV Size 203.92 MiB / not usable 3.92 MiB
Allocatable NO <-----表示已經關閉了該PV
PE Size 4.00 MiB
Total PE 50
Free PE 0
Allocated PE 50
PV UUID S2ane6-nlFG-uSNR-35NP-Yxa6-cXRb-r8E8mK
……
將sda6的數據移走：
pvmove -i 1 /dev/sda6
-i 1是每1秒鍾報告一次數據遷移的進度。
[root@liuhg /]# pvmove -i 1 /dev/sda6
/dev/sda6: Moved: 38.0%
/dev/sda6: Moved: 84.0%
/dev/sda6: Moved: 100.0%
重新用pvdisplay -m
顯示如下：
……
--- Physical volume ---
PV Name /dev/sda6
VG Name liuhg_disk
PV Size 203.92 MiB / not usable 3.92 MiB
Allocatable NO
PE Size 4.00 MiB
Total PE 50
Free PE 50 <----顯示完全空閑和Total PE數一致
Allocated PE 0
PV UUID S2ane6-nlFG-uSNR-35NP-Yxa6-cXRb-r8E8mK
……
從卷組里把sda6刪除:
[root@liuhg /]# vgrece liuhg_disk /dev/sda6
Removed "/dev/sda6" from volume group "liuhg_disk"
pvdisplay -m再看看吧：
--- NEW Physical volume --- <-----還告訴你這是一個新的PV ^_^
PV Name /dev/sda6
VG Name <-----空了
PV Size 203.92 MiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID S2ane6-nlFG-uSNR-35NP-Yxa6-cXRb-r8E8mK
到此vgdisplay -v能看到已經沒有了/dev/sda6了。重新掛載/home
[root@liuhg /]# mount /dev/liuhg_disk/home /home
[root@liuhg /]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 2.0G 546M 1.3G 30% /
tmpfs 504M 0 504M 0% /dev/shm
/dev/mapper/liuhg_disk-home
2.2G 1.8G 42M 98% /home
進去看看數據，一個都沒丟。
『陸』 關於將linux分區初始化為物理卷pv
創建pv的時候；這個物理設備本身是不應該有文件系統的；所以壓根不會說數據之說
在pv的基礎上建立vg;在vg的基礎上建立lv；在lv的基礎上才是文件系統；
『柒』 一道關於pv=nRT的物理題!
設 標准大氣壓為 p
因為 標准狀況下(0攝氏度 101KP) 1L氧氣的體積22.4L //這是常數
（這里的T不是攝氏度 是熱力學溫度 273的關系）
由pv=nRT
得
p * 22.4L = 1mol * R * （70+273）°-----①
已知
5p * 1.5L = n * R * 273°-------②
① / ②
得 n =0.1mol
『捌』 如何安全的刪除Linux LVM中的PV物理卷(硬碟或分區)
情況介紹：
一、由於硬碟或者分區的操作方式其實都一樣，所以我這里就以分區為例。
二、/home分區2.6G，由如下pv組成：
/dev/sda5 100M
/dev/sda6 200M
/dev/sda7 300M
/dev/sda8 400M
/dev/sda9 500M
/dev/sda10 600M
/dev/sda11 500M
很碎對吧?^_^因為測試。
三、隨機寫了一堆文件進去，用量達到了2G，空閑500M
四、准備將sda6這個200M的PV卸掉(卸掉的容量必須小於空閑容量)
好了開始具體操作了。
卸載分區(縮小操作必須卸載才能進行)：
umount /home
縮小分區：
e2fsck -f /dev/liuhg_disk/home
resize2fs /dev/liuhg_disk/home 2200M
首先將分區縮小到2200M這是為了給sda6騰出空間，sda6為200M，而我騰出了400M，因此應該是足夠的。
縮小邏輯卷：
lvrece -L 2200M /dev/liuhg_disk/home
分區縮小了用到的邏輯卷也要隨著縮小，並查看PV使用的狀態：
pvdisplay -m
顯示如下：
--- Physical volume ---
PV Name /dev/sda5
VG Name liuhg_disk
PV Size 103.26 MiB / not usable 3.26 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 25
Free PE 0
Allocated PE 25
PV UUID 5lnx52-b4jc-OOfZ-f2QA-ttdQ-DZeD-Ce3rb3
--- Physical Segments ---
Physical extent 0 to 24:
Logical volume /dev/liuhg_disk/home
Logical extents 0 to 24
--- Physical volume ---
PV Name /dev/sda6
VG Name liuhg_disk
PV Size 203.92 MiB / not usable 3.92 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 50
Free PE 0 <-----太悲劇了，sda6里寫滿了數據一點不剩
Allocated PE 50 <-----這50PE的數據要挪走才行，否則數據就丟了，並且存放的地方也必須是連續的至少50PE
PV UUID S2ane6-nlFG-uSNR-35NP-Yxa6-cXRb-r8E8mK
--- Physical Segments ---
Physical extent 0 to 49:
Logical volume /dev/liuhg_disk/home
Logical extents 25 to 74
--- Physical volume ---
PV Name /dev/sda7
VG Name liuhg_disk
PV Size 305.89 MiB / not usable 1.89 MiB
Allocatable yes
PE Size 4.00 MiB
Total PE 76
Free PE 76 <---這個分區有76個空餘，因此預計裝那50個是不會有問題的
Allocated PE 0
PV UUID 9CFnlx-CAEw-CSul-Rig9-FiCN-zK0a-oGmTEP
--- Physical Segments ---
Physical extent 0 to 75:
FREE
--- Physical volume ---
PV Name /dev/sda8
VG Name liuhg_disk
PV Size 407.87 MiB / not usable 3.87 MiB
Allocatable yes
PE Size 4.00 MiB
Total PE 101
Free PE 60
Allocated PE 41
PV UUID X0I8p0-x2xr-2xLG-QQD4-jbtS-3C4i-xPn4Bl
--- Physical Segments ---
Physical extent 0 to 40:
Logical volume /dev/liuhg_disk/home
Logical extents 471 to 511
Physical extent 41 to 100:
FREE
--- Physical volume ---
PV Name /dev/sda9
VG Name liuhg_disk
PV Size 509.84 MiB / not usable 1.84 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 127
Free PE 0
Allocated PE 127
PV UUID avJQaA-oMKt-NEoJ-ojBK-2Csc-1dca-1mh6Ue
--- Physical Segments ---
Physical extent 0 to 126:
Logical volume /dev/liuhg_disk/home
Logical extents 225 to 351
--- Physical volume ---
PV Name /dev/sda10
VG Name liuhg_disk
PV Size 603.98 MiB / not usable 3.98 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 150
Free PE 0
Allocated PE 150
PV UUID JlMIAF-A49n-M6HA-ZLXf-d8nS-pfZr-YeQsKT
--- Physical Segments ---
Physical extent 0 to 149:
Logical volume /dev/liuhg_disk/home
Logical extents 75 to 224
--- Physical volume ---
PV Name /dev/sda11
VG Name liuhg_disk
PV Size 478.47 MiB / not usable 2.47 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 119
Free PE 0
Allocated PE 119
PV UUID xnHJNA-tDVx-dryX-KM1x-g96Y-sptI-9iUOcU
--- Physical Segments ---
Physical extent 0 to 118:
Logical volume /dev/liuhg_disk/home
Logical extents 352 to 470
將sda6設置為離線狀態：
pvchange -xn /dev/sda6
使用pvdisplay -m
顯示如下：
……
--- Physical volume ---
PV Name /dev/sda6
VG Name liuhg_disk
PV Size 203.92 MiB / not usable 3.92 MiB
Allocatable NO <-----表示已經關閉了該PV
PE Size 4.00 MiB
Total PE 50
Free PE 0
Allocated PE 50
PV UUID S2ane6-nlFG-uSNR-35NP-Yxa6-cXRb-r8E8mK
……
將sda6的數據移走：
pvmove -i 1 /dev/sda6
-i 1是每1秒鍾報告一次數據遷移的進度。
[root@liuhg /]# pvmove -i 1 /dev/sda6
/dev/sda6: Moved: 38.0%
/dev/sda6: Moved: 84.0%
/dev/sda6: Moved: 100.0%
重新用pvdisplay -m
顯示如下：
……
--- Physical volume ---
PV Name /dev/sda6
VG Name liuhg_disk
PV Size 203.92 MiB / not usable 3.92 MiB
Allocatable NO
PE Size 4.00 MiB
Total PE 50
Free PE 50 <----顯示完全空閑和Total PE數一致
Allocated PE 0
PV UUID S2ane6-nlFG-uSNR-35NP-Yxa6-cXRb-r8E8mK
……
從卷組里把sda6刪除:
[root@liuhg /]# vgrece liuhg_disk /dev/sda6
Removed "/dev/sda6" from volume group "liuhg_disk"
pvdisplay -m再看看吧：
--- NEW Physical volume --- <-----還告訴你這是一個新的PV ^_^
PV Name /dev/sda6
VG Name <-----空了
PV Size 203.92 MiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID S2ane6-nlFG-uSNR-35NP-Yxa6-cXRb-r8E8mK
到此vgdisplay -v能看到已經沒有了/dev/sda6了。重新掛載/home
[root@liuhg /]# mount /dev/liuhg_disk/home /home
[root@liuhg /]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 2.0G 546M 1.3G 30% /
tmpfs 504M 0 504M 0% /dev/shm
/dev/mapper/liuhg_disk-home
2.2G 1.8G 42M 98% /home
進去看看數據，一個都沒丟。
『玖』 PV和PE各指什麼
PV（Physical Volume，物理卷）
PE（Physical Extent）
LVM（Logical Volume Manager）是操作系統中一個磁碟管理子系統，而不是文件系統！
在LVM里，一個PV（Physical Volume，物理卷）對應且只對應一個物理硬碟，一個或者多個PV組成一個VG（Volume Group，卷組），而從一個VG里又可以虛擬劃分出若干個LV（Logical Volume，邏輯卷），真正的文件系統是創建在LV上面的
非連續空間分配主要表現在給LV分配空間時，PE的不連續性。這種非連續性空間分配策略是LVM在創建LV時的默認策略，優點是可以跨多個PV，充分利用有效的剩餘空間，同時非常方便擴文件系統，但是缺點之一是可能造成磁碟分配不均衡。當然，可以用lvextend來指定分配到哪個硬碟，但是效果不理想。相比之下，連續性空間分配策略對PE的分配要求要高得多：
·首先是不能跨多個PV
·PE必須按升序連續分配