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1 | Directory Backend | |
2 | ----------------- | |
3 | ifdef::wiki[] | |
4 | :pve-toplevel: | |
5 | :title: Storage: Directory | |
6 | endif::wiki[] | |
7 | ||
8 | Storage pool type: `dir` | |
9 | ||
10 | {pve} can use local directories or locally mounted shares for | |
11 | storage. A directory is a file level storage, so you can store any | |
12 | content type like virtual disk images, containers, templates, ISO images | |
13 | or backup files. | |
14 | ||
15 | NOTE: You can mount additional storages via standard linux `/etc/fstab`, | |
16 | and then define a directory storage for that mount point. This way you | |
17 | can use any file system supported by Linux. | |
18 | ||
19 | This backend assumes that the underlying directory is POSIX | |
20 | compatible, but nothing else. This implies that you cannot create | |
21 | snapshots at the storage level. But there exists a workaround for VM | |
22 | images using the `qcow2` file format, because that format supports | |
23 | snapshots internally. | |
24 | ||
25 | TIP: Some storage types do not support `O_DIRECT`, so you can't use | |
26 | cache mode `none` with such storages. Simply use cache mode | |
27 | `writeback` instead. | |
28 | ||
29 | We use a predefined directory layout to store different content types | |
30 | into different sub-directories. This layout is used by all file level | |
31 | storage backends. | |
32 | ||
33 | .Directory layout | |
34 | [width="100%",cols="d,m",options="header"] | |
35 | |=========================================================== | |
36 | |Content type |Subdir | |
37 | |VM images |`images/<VMID>/` | |
38 | |ISO images |`template/iso/` | |
39 | |Container templates |`template/cache/` | |
40 | |Backup files |`dump/` | |
41 | |=========================================================== | |
42 | ||
43 | ||
44 | Configuration | |
45 | ~~~~~~~~~~~~~ | |
46 | ||
47 | This backend supports all common storage properties, and adds an | |
48 | additional property called `path` to specify the directory. This | |
49 | needs to be an absolute file system path. | |
50 | ||
51 | .Configuration Example (`/etc/pve/storage.cfg`) | |
52 | ---- | |
53 | dir: backup | |
54 | path /mnt/backup | |
55 | content backup | |
56 | maxfiles 7 | |
57 | ---- | |
58 | ||
59 | Above configuration defines a storage pool called `backup`. That pool | |
60 | can be used to store up to 7 backups (`maxfiles 7`) per VM. The real | |
61 | path for the backup files is `/mnt/backup/dump/...`. | |
62 | ||
63 | ||
64 | File naming conventions | |
65 | ~~~~~~~~~~~~~~~~~~~~~~~ | |
66 | ||
67 | This backend uses a well defined naming scheme for VM images: | |
68 | ||
69 | vm-<VMID>-<NAME>.<FORMAT> | |
70 | ||
71 | `<VMID>`:: | |
72 | ||
73 | This specifies the owner VM. | |
74 | ||
75 | `<NAME>`:: | |
76 | ||
77 | This can be an arbitrary name (`ascii`) without white space. The | |
78 | backend uses `disk-[N]` as default, where `[N]` is replaced by an | |
79 | integer to make the name unique. | |
80 | ||
81 | `<FORMAT>`:: | |
82 | ||
83 | Specifies the image format (`raw|qcow2|vmdk`). | |
84 | ||
85 | When you create a VM template, all VM images are renamed to indicate | |
86 | that they are now read-only, and can be used as a base image for clones: | |
87 | ||
88 | base-<VMID>-<NAME>.<FORMAT> | |
89 | ||
90 | NOTE: Such base images are used to generate cloned images. So it is | |
91 | important that those files are read-only, and never get modified. The | |
92 | backend changes the access mode to `0444`, and sets the immutable flag | |
93 | (`chattr +i`) if the storage supports that. | |
94 | ||
95 | ||
96 | Storage Features | |
97 | ~~~~~~~~~~~~~~~~ | |
98 | ||
99 | As mentioned above, most file systems do not support snapshots out | |
100 | of the box. To workaround that problem, this backend is able to use | |
101 | `qcow2` internal snapshot capabilities. | |
102 | ||
103 | Same applies to clones. The backend uses the `qcow2` base image | |
104 | feature to create clones. | |
105 | ||
106 | .Storage features for backend `dir` | |
107 | [width="100%",cols="m,m,3*d",options="header"] | |
108 | |============================================================================== | |
109 | |Content types |Image formats |Shared |Snapshots |Clones | |
110 | |images rootdir vztmpl iso backup |raw qcow2 vmdk subvol |no |qcow2 |qcow2 | |
111 | |============================================================================== | |
112 | ||
113 | ||
114 | Examples | |
115 | ~~~~~~~~ | |
116 | ||
117 | Please use the following command to allocate a 4GB image on storage `local`: | |
118 | ||
119 | # pvesm alloc local 100 vm-100-disk10.raw 4G | |
120 | Formatting '/var/lib/vz/images/100/vm-100-disk10.raw', fmt=raw size=4294967296 | |
121 | successfully created 'local:100/vm-100-disk10.raw' | |
122 | ||
123 | NOTE: The image name must conform to above naming conventions. | |
124 | ||
125 | The real file system path is shown with: | |
126 | ||
127 | # pvesm path local:100/vm-100-disk10.raw | |
128 | /var/lib/vz/images/100/vm-100-disk10.raw | |
129 | ||
130 | And you can remove the image with: | |
131 | ||
132 | # pvesm free local:100/vm-100-disk10.raw | |
133 | ||
134 | ||
135 | ifdef::wiki[] | |
136 | ||
137 | See Also | |
138 | ~~~~~~~~ | |
139 | ||
140 | * link:/wiki/Storage[Storage] | |
141 | ||
142 | endif::wiki[] | |
143 | ||
144 |