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1 | [[storage_directory]] | |
2 | Directory Backend | |
3 | ----------------- | |
4 | ifdef::wiki[] | |
5 | :pve-toplevel: | |
6 | :title: Storage: Directory | |
7 | endif::wiki[] | |
8 | ||
9 | Storage pool type: `dir` | |
10 | ||
11 | {pve} can use local directories or locally mounted shares for | |
12 | storage. A directory is a file level storage, so you can store any | |
13 | content type like virtual disk images, containers, templates, ISO images | |
14 | or backup files. | |
15 | ||
16 | NOTE: You can mount additional storages via standard linux `/etc/fstab`, | |
17 | and then define a directory storage for that mount point. This way you | |
18 | can use any file system supported by Linux. | |
19 | ||
20 | This backend assumes that the underlying directory is POSIX | |
21 | compatible, but nothing else. This implies that you cannot create | |
22 | snapshots at the storage level. But there exists a workaround for VM | |
23 | images using the `qcow2` file format, because that format supports | |
24 | snapshots internally. | |
25 | ||
26 | TIP: Some storage types do not support `O_DIRECT`, so you can't use | |
27 | cache mode `none` with such storages. Simply use cache mode | |
28 | `writeback` instead. | |
29 | ||
30 | We use a predefined directory layout to store different content types | |
31 | into different sub-directories. This layout is used by all file level | |
32 | storage backends. | |
33 | ||
34 | .Directory layout | |
35 | [width="100%",cols="d,m",options="header"] | |
36 | |=========================================================== | |
37 | |Content type |Subdir | |
38 | |VM images |`images/<VMID>/` | |
39 | |ISO images |`template/iso/` | |
40 | |Container templates |`template/cache/` | |
41 | |Backup files |`dump/` | |
42 | |Snippets |`snippets/` | |
43 | |=========================================================== | |
44 | ||
45 | ||
46 | Configuration | |
47 | ~~~~~~~~~~~~~ | |
48 | ||
49 | This backend supports all common storage properties, and adds an | |
50 | additional property called `path` to specify the directory. This | |
51 | needs to be an absolute file system path. | |
52 | ||
53 | .Configuration Example (`/etc/pve/storage.cfg`) | |
54 | ---- | |
55 | dir: backup | |
56 | path /mnt/backup | |
57 | content backup | |
58 | maxfiles 7 | |
59 | ---- | |
60 | ||
61 | Above configuration defines a storage pool called `backup`. That pool | |
62 | can be used to store up to 7 backups (`maxfiles 7`) per VM. The real | |
63 | path for the backup files is `/mnt/backup/dump/...`. | |
64 | ||
65 | ||
66 | File naming conventions | |
67 | ~~~~~~~~~~~~~~~~~~~~~~~ | |
68 | ||
69 | This backend uses a well defined naming scheme for VM images: | |
70 | ||
71 | vm-<VMID>-<NAME>.<FORMAT> | |
72 | ||
73 | `<VMID>`:: | |
74 | ||
75 | This specifies the owner VM. | |
76 | ||
77 | `<NAME>`:: | |
78 | ||
79 | This can be an arbitrary name (`ascii`) without white space. The | |
80 | backend uses `disk-[N]` as default, where `[N]` is replaced by an | |
81 | integer to make the name unique. | |
82 | ||
83 | `<FORMAT>`:: | |
84 | ||
85 | Specifies the image format (`raw|qcow2|vmdk`). | |
86 | ||
87 | When you create a VM template, all VM images are renamed to indicate | |
88 | that they are now read-only, and can be used as a base image for clones: | |
89 | ||
90 | base-<VMID>-<NAME>.<FORMAT> | |
91 | ||
92 | NOTE: Such base images are used to generate cloned images. So it is | |
93 | important that those files are read-only, and never get modified. The | |
94 | backend changes the access mode to `0444`, and sets the immutable flag | |
95 | (`chattr +i`) if the storage supports that. | |
96 | ||
97 | ||
98 | Storage Features | |
99 | ~~~~~~~~~~~~~~~~ | |
100 | ||
101 | As mentioned above, most file systems do not support snapshots out | |
102 | of the box. To workaround that problem, this backend is able to use | |
103 | `qcow2` internal snapshot capabilities. | |
104 | ||
105 | Same applies to clones. The backend uses the `qcow2` base image | |
106 | feature to create clones. | |
107 | ||
108 | .Storage features for backend `dir` | |
109 | [width="100%",cols="m,m,3*d",options="header"] | |
110 | |============================================================================== | |
111 | |Content types |Image formats |Shared |Snapshots |Clones | |
112 | |images rootdir vztmpl iso backup snippets |raw qcow2 vmdk subvol |no |qcow2 |qcow2 | |
113 | |============================================================================== | |
114 | ||
115 | ||
116 | Examples | |
117 | ~~~~~~~~ | |
118 | ||
119 | Please use the following command to allocate a 4GB image on storage `local`: | |
120 | ||
121 | # pvesm alloc local 100 vm-100-disk10.raw 4G | |
122 | Formatting '/var/lib/vz/images/100/vm-100-disk10.raw', fmt=raw size=4294967296 | |
123 | successfully created 'local:100/vm-100-disk10.raw' | |
124 | ||
125 | NOTE: The image name must conform to above naming conventions. | |
126 | ||
127 | The real file system path is shown with: | |
128 | ||
129 | # pvesm path local:100/vm-100-disk10.raw | |
130 | /var/lib/vz/images/100/vm-100-disk10.raw | |
131 | ||
132 | And you can remove the image with: | |
133 | ||
134 | # pvesm free local:100/vm-100-disk10.raw | |
135 | ||
136 | ||
137 | ifdef::wiki[] | |
138 | ||
139 | See Also | |
140 | ~~~~~~~~ | |
141 | ||
142 | * link:/wiki/Storage[Storage] | |
143 | ||
144 | endif::wiki[] | |
145 | ||
146 |