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1 | Directory Backend | |
2 | ----------------- | |
3 | include::attributes.txt[] | |
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 | |=========================================================== | |
43 | ||
44 | ||
45 | Configuration | |
46 | ~~~~~~~~~~~~~ | |
47 | ||
48 | This backend supports all common storage properties, and adds an | |
49 | additional property called `path` to specify the directory. This | |
50 | needs to be an absolute file system path. | |
51 | ||
52 | .Configuration Example (`/etc/pve/storage.cfg`) | |
53 | ---- | |
54 | dir: backup | |
55 | path /mnt/backup | |
56 | content backup | |
57 | maxfiles 7 | |
58 | ---- | |
59 | ||
60 | Above configuration defines a storage pool called `backup`. That pool | |
61 | can be used to store up to 7 backups (`maxfiles 7`) per VM. The real | |
62 | path for the backup files is `/mnt/backup/dump/...`. | |
63 | ||
64 | ||
65 | File naming conventions | |
66 | ~~~~~~~~~~~~~~~~~~~~~~~ | |
67 | ||
68 | This backend uses a well defined naming scheme for VM images: | |
69 | ||
70 | vm-<VMID>-<NAME>.<FORMAT> | |
71 | ||
72 | `<VMID>`:: | |
73 | ||
74 | This specifies the owner VM. | |
75 | ||
76 | `<NAME>`:: | |
77 | ||
78 | This can be an arbitrary name (`ascii`) without white space. The | |
79 | backend uses `disk-[N]` as default, where `[N]` is replaced by an | |
80 | integer to make the name unique. | |
81 | ||
82 | `<FORMAT>`:: | |
83 | ||
84 | Specifies the image format (`raw|qcow2|vmdk`). | |
85 | ||
86 | When you create a VM template, all VM images are renamed to indicate | |
87 | that they are now read-only, and can be used as a base image for clones: | |
88 | ||
89 | base-<VMID>-<NAME>.<FORMAT> | |
90 | ||
91 | NOTE: Such base images are used to generate cloned images. So it is | |
92 | important that those files are read-only, and never get modified. The | |
93 | backend changes the access mode to `0444`, and sets the immutable flag | |
94 | (`chattr +i`) if the storage supports that. | |
95 | ||
96 | ||
97 | Storage Features | |
98 | ~~~~~~~~~~~~~~~~ | |
99 | ||
100 | As mentioned above, most file systems do not support snapshots out | |
101 | of the box. To workaround that problem, this backend is able to use | |
102 | `qcow2` internal snapshot capabilities. | |
103 | ||
104 | Same applies to clones. The backend uses the `qcow2` base image | |
105 | feature to create clones. | |
106 | ||
107 | .Storage features for backend `dir` | |
108 | [width="100%",cols="m,m,3*d",options="header"] | |
109 | |============================================================================== | |
110 | |Content types |Image formats |Shared |Snapshots |Clones | |
111 | |images rootdir vztempl iso backup |raw qcow2 vmdk subvol |no |qcow2 |qcow2 | |
112 | |============================================================================== | |
113 | ||
114 | ||
115 | Examples | |
116 | ~~~~~~~~ | |
117 | ||
118 | Please use the following command to allocate a 4GB image on storage `local`: | |
119 | ||
120 | # pvesm alloc local 100 vm-100-disk10.raw 4G | |
121 | Formatting '/var/lib/vz/images/100/vm-100-disk10.raw', fmt=raw size=4294967296 | |
122 | successfully created 'local:100/vm-100-disk10.raw' | |
123 | ||
124 | NOTE: The image name must conform to above naming conventions. | |
125 | ||
126 | The real file system path is shown with: | |
127 | ||
128 | # pvesm path local:100/vm-100-disk10.raw | |
129 | /var/lib/vz/images/100/vm-100-disk10.raw | |
130 | ||
131 | And you can remove the image with: | |
132 | ||
133 | # pvesm free local:100/vm-100-disk10.raw | |
134 | ||
135 | ||
136 | ifdef::wiki[] | |
137 | ||
138 | See Also | |
139 | ~~~~~~~~ | |
140 | ||
141 | * link:/wiki/Storage[Storage] | |
142 | ||
143 | endif::wiki[] | |
144 | ||
145 |