Storage: Directory: Difference between revisions
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Revision as of 11:03, 19 September 2016
Storage pool type: dir
Proxmox VE can use local directories or locally mounted shares for storage. A directory is a file level storage, so you can store any content type like virtual disk images, containers, templates, ISO images or backup files.
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You can mount additional storages via standard linux /etc/fstab, and then define a directory storage for that mount point. This way you can use any file system supported by Linux. |
This backend assumes that the underlying directory is POSIX compatible, but nothing else. This implies that you cannot create snapshots at the storage level. But there exists a workaround for VM images using the qcow2 file format, because that format supports snapshots internally.
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Some storage types do not support O_DIRECT, so you can’t use cache mode none with such storages. Simply use cache mode writeback instead. |
We use a predefined directory layout to store different content types into different sub-directories. This layout is used by all file level storage backends.
Content type | Subdir |
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VM images |
images/<VMID>/ |
ISO images |
template/iso/ |
Container templates |
template/cache/ |
Backup files |
dump/ |
Snippets |
snippets/ |
Configuration
This backend supports all common storage properties, and adds two additional properties. The path property is used to specify the directory. This needs to be an absolute file system path.
The optional content-dirs property allows for the default layout to be changed. It consists of a comma-separated list of identifiers in the following format:
vtype=path
Where vtype is one of the allowed content types for the storage, and path is a path relative to the mountpoint of the storage.
dir: backup path /mnt/backup content backup prune-backups keep-last=7 max-protected-backups 3 content-dirs backup=custom/backup/dir
The above configuration defines a storage pool called backup. That pool can be used to store up to 7 regular backups (keep-last=7) and 3 protected backups per VM. The real path for the backup files is /mnt/backup/custom/backup/dir/....
File naming conventions
This backend uses a well defined naming scheme for VM images:
vm-<VMID>-<NAME>.<FORMAT>
- <VMID>
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This specifies the owner VM.
- <NAME>
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This can be an arbitrary name (ascii) without white space. The backend uses disk-[N] as default, where [N] is replaced by an integer to make the name unique.
- <FORMAT>
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Specifies the image format (raw|qcow2|vmdk).
When you create a VM template, all VM images are renamed to indicate that they are now read-only, and can be used as a base image for clones:
base-<VMID>-<NAME>.<FORMAT>
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Such base images are used to generate cloned images. So it is important that those files are read-only, and never get modified. The backend changes the access mode to 0444, and sets the immutable flag (chattr +i) if the storage supports that. |
Storage Features
As mentioned above, most file systems do not support snapshots out of the box. To workaround that problem, this backend is able to use qcow2 internal snapshot capabilities.
Same applies to clones. The backend uses the qcow2 base image feature to create clones.
Content types | Image formats | Shared | Snapshots | Clones |
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images rootdir vztmpl iso backup snippets |
raw qcow2 vmdk subvol |
no |
qcow2 |
qcow2 |
Examples
Please use the following command to allocate a 4GB image on storage local:
# pvesm alloc local 100 vm-100-disk10.raw 4G Formatting '/var/lib/vz/images/100/vm-100-disk10.raw', fmt=raw size=4294967296 successfully created 'local:100/vm-100-disk10.raw'
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The image name must conform to above naming conventions. |
The real file system path is shown with:
# pvesm path local:100/vm-100-disk10.raw /var/lib/vz/images/100/vm-100-disk10.raw
And you can remove the image with:
# pvesm free local:100/vm-100-disk10.raw