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1 | Logical Volume Manager (LVM) |
2 | ---------------------------- | |
5f09af76 DM |
3 | ifdef::wiki[] |
4 | :pve-toplevel: | |
5 | endif::wiki[] | |
6 | ||
08152ae6 | 7 | Most people install {pve} directly on a local disk. The {pve} |
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8 | installation CD offers several options for local disk management, and |
9 | the current default setup uses LVM. The installer let you select a | |
10 | single disk for such setup, and uses that disk as physical volume for | |
8c1189b6 | 11 | the **V**olume **G**roup (VG) `pve`. The following output is from a |
8b849dc3 | 12 | test installation using a small 8GB disk: |
08152ae6 | 13 | |
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14 | ---- |
15 | # pvs | |
16 | PV VG Fmt Attr PSize PFree | |
17 | /dev/sda3 pve lvm2 a-- 7.87g 876.00m | |
18 | ||
19 | # vgs | |
20 | VG #PV #LV #SN Attr VSize VFree | |
21 | pve 1 3 0 wz--n- 7.87g 876.00m | |
22 | ---- | |
23 | ||
24 | The installer allocates three **L**ogical **V**olumes (LV) inside this | |
25 | VG: | |
26 | ||
27 | ---- | |
28 | # lvs | |
29 | LV VG Attr LSize Pool Origin Data% Meta% | |
30 | data pve twi-a-tz-- 4.38g 0.00 0.63 | |
31 | root pve -wi-ao---- 1.75g | |
32 | swap pve -wi-ao---- 896.00m | |
33 | ---- | |
34 | ||
8c1189b6 | 35 | root:: Formatted as `ext4`, and contains the operation system. |
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36 | |
37 | swap:: Swap partition | |
38 | ||
39 | data:: This volume uses LVM-thin, and is used to store VM | |
40 | images. LVM-thin is preferable for this task, because it offers | |
41 | efficient support for snapshots and clones. | |
08152ae6 | 42 | |
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43 | For {pve} versions up to 4.1, the installer creates a Logical Volume |
44 | called ``data'' which is mounted at `/var/lib/vz` | |
45 | Starting from 4.2 the Logical Volume ``data'' is a LVM thin volume, used | |
46 | for block based storage of guest systems, and `/var/lib/vz` is simply a | |
47 | directory on the root file system. | |
48 | ||
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49 | Hardware |
50 | ~~~~~~~~ | |
51 | ||
52 | We highly recommend to use a hardware RAID controller (with BBU) for | |
53 | such setups. This increases performance, provides redundancy, and make | |
54 | disk replacements easier (hot-pluggable). | |
55 | ||
56 | LVM itself does not need any special hardware, and memory requirements | |
57 | are very low. | |
58 | ||
59 | ||
60 | Bootloader | |
61 | ~~~~~~~~~~ | |
62 | ||
63 | We install two boot loaders by default. The first partition contains | |
64 | the standard GRUB boot loader. The second partition is an **E**FI **S**ystem | |
65 | **P**artition (ESP), which makes it possible to boot on EFI systems. | |
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66 | |
67 | ||
68 | Creating a Volume Group | |
69 | ~~~~~~~~~~~~~~~~~~~~~~~ | |
70 | ||
71 | Let's assume we have an empty disk `/dev/sdb`, onto which we want to | |
72 | create a Volume Group named ``vmdata''. | |
73 | ||
74 | First create a partition. | |
75 | ||
76 | # sgdisk -N 1 /dev/sdb | |
77 | ||
78 | Create a **P**hysical **V**olumes (PV) without confirmation and 250K | |
79 | metadatasize. | |
80 | ||
81 | # pvcreate --metadatasize 250k -y -ff /dev/sdb1 | |
82 | ||
83 | Create a **V**olume **G**roup (VG) named ``vmdata'' on `/dev/sdb1` | |
84 | ||
85 | # vgcreate vmdata /dev/sdb1 | |
86 | ||
87 | ||
88 | Creating an extra LV for `/var/lib/vz` | |
89 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
90 | ||
91 | This can be easily done by creating a new thin LV. | |
92 | ||
93 | # lvcreate -n <Name> -V <Size[M,G,T]> <VG>/<LVThin_pool> | |
94 | ||
95 | A real world example: | |
96 | ||
97 | # lvcreate -n vz -V 10G pve/data | |
98 | ||
99 | Now a filesystem must be created on the LV. | |
100 | ||
101 | # mkfs.ext4 /dev/data/vz | |
102 | ||
103 | At last this has to be mounted. | |
104 | ||
105 | WARNING: be sure that `/var/lib/vz` is empty. On a default installation it's not. | |
106 | ||
107 | To make it always accessible add the following line in `/etc/fstab`. | |
108 | ||
109 | # echo '/dev/pve/vz /var/lib/vz ext4 defaults 0 2' >> /etc/fstab | |
110 | ||
111 | ||
112 | Resizing the thin pool | |
113 | ~~~~~~~~~~~~~~~~~~~~~~ | |
114 | ||
115 | NOTE: When extending the data pool, the metadata pool must be extended with it. | |
116 | ||
117 | Resize the LV and the metadata pool can be achieved with the following command. | |
118 | ||
119 | # lvresize --size +<size[\M,G,T]> --poolmetadatasize +<size[\M,G]> <VG>/<LVThin_pool> | |
120 | ||
121 | ||
122 | Create a LVM-Thin pool | |
123 | ~~~~~~~~~~~~~~~~~~~~~~ | |
124 | ||
125 | A thin pool has to be created on top of a volume group. | |
126 | How to create a Volume Group see Section LVM. | |
127 | ||
128 | # lvcreate -L 80G -T -n vmstore vmdata |