Backup Storage

ZStack 3.10.0>Product Manuals>Maintenance Manual>Hardware>Backup Storage

A backup storage is a storage server used to store image templates including ISO.

A backup storage must be attached to a zone before the resources on the zone can access it. Note that you can share images across multiple zones by using the backup storage, as shown in Backup Storage.
Figure 1. Backup Storage
To better manage backup storages and zones, the UI specifies that one backup storage can only correspond to one zone. In the UI, when you add a backup storage, the backup storage will be attached to the current zone by default. When you delete a zone, the backup storage attached to the zone will also be deleted.

Backup Storage | Primary Storage

The types of both primary storage and backup storage are strongly associated, as shown in Relations Between Backup Storage and Primary Storage.

Table 1. Relations Between Primary Storage and Backup Storage
PS/BS	ImageStore	SFTP	Ceph
LocalStorage	○	○	×
NFS	○	○	×
Shared Mount Point	○	○	×
Ceph	○	×	○
Shared Block	○	×	×

When primary storages are LocalStorage, NFS, or Shared Mount Point, the default type for backup storages is ImageStore, or SFTP.
When primary storages are NFS or Shared Mount Point, the corresponding shared directories can be manually attached to the local directories of the corresponding backup storages. In this regard, both primary storages and backup storages can use the network shared storage.
When primary storages are Ceph, backup storages can use the primary storages in the same Ceph cluster as backup storages. In addition, backup storages can use the primary storages with the ImageStore type as backup storages.
When primary storages are Shared Block, the default type for backup storages is ImageStore.

Notice

When you use backup storages, note that:

The following types of backup storage are supported:
1. ImageStore
  - Image files are stored by means of image segmentation. Incremental storage is supported.
  - Snapshots and images can be created when VM instances are running or stopped.
  - When VM instances are cloned without data volumes, the VM instances that are running, paused, or stopped can be cloned.
  - When VM instances are cloned with data volumes, the VM instances that are running, paused, or stopped, and with storage types of LocalStorage, NFS, Shared Mount Point, Ceph, or Shared Block can be cloned.
  - Images can be synchronized across ImageStore backup storages within the same management network.
  - The existing images can be obtained. In addition, you can obtain the existing image files under the URL path in the backup storage.
2. SFTP
  - Only the SFTP Community edition is supported.
  - Image files are stored by means of files.
  - Snapshots and images can be created when VM instances are stopped.
  - On the backup storage, the images that you created can be accessed according to the corresponding backup storage path, and can be copied to other cloud environments for direct use.
3. Ceph
  - Image files are stored by means of Ceph distributed block storages.
  - Snapshots and images can be created when VM instances are running or stopped.
  - When VM instances are cloned without data volumes, the VM instances that are running, paused, or stopped can be cloned.
  - VM instances cannot be cloned with data volumes.
  - Images can only be exported on backup storages.
    Assume that the image path you use is ceph://bak-t-c9923f9821bf45498fdf9cdfa1749943/61ece0adc7244b0cbd12dafbc5494f0c.
    Then, run the following commands on the backup storage:
```
rbd export -p bak-t-c9923f9821bf45498fdf9cdfa1749943 --image 61ece0adc7244b0cbd12dafbc5494f0c --path /root/export-test.image  # bak-t-c9923f9821bf45498fdf9cdfa1749943 is the name of the pool where the image resides. # 61ece0adc7244b0cbd12dafbc5494f0c is the image name. # /root/export-test.image is the name of the exported target file.
```
After you delete a backup storage, all image files will also be deleted and cannot be restored. Please exercise caution. The delete operation only removes the information about the backup storage and images recorded in ZStack. Actual data will not be deleted.
The following are some details about backup storage cloning and snapshot:
- Online cloning: ImageStore backup storages can be cloned with or without volumes. Ceph backup storages can be cloned without volumes.
- Offline cloning: ImageStore backup storages can be cloned with or without volumes. Ceph backup storages can be cloned without volumes.
- Online snapshot: You can create snapshots for ImageStore and Ceph backup storages online.
- Offline snapshot: You can create snapshots for ImageStore, SFTP, and Ceph backup storages when VM instances are shut down.
- Online image creation: You can create images for ImageStore and Ceph backup storages online.
- Offline image creation: You can create images for ImageStore, SFTP, and Ceph backup storages when VM instances are shut down.
You can clean up the invalid data that was completely deleted in a backup storage to release the storage space.
Note:
- For example, after you completely delete an image file as well as the VM instances that use the image, you can perform data cleaning to release the storage space of the backup storage.
- Only ImageStore backup storages support the data cleaning operation.

ImageStore

ImageStore stores image files in the form of image segmentation. When the type of a primary storages is LocalStorage, NFS, Shared Mount Point, Ceph, and Shared Block, you can use the primary storage with ImageStore backup storages.

Image files are stored by means of image segmentation. Incremental storage is supported.
Snapshots and images can be created when VM instances are running or stopped.
When VM instances are cloned without data volumes, the VM instances that are running, paused, or stopped can be cloned.
When VM instances are cloned with data volumes, the VM instances that are running, paused, or stopped, and with storage types of LocalStorage, NFS, Shared Mount Point, Ceph, or Shared Block can be cloned.
Images can be synchronized across ImageStore backup storages within the same management network.
The existing images can be obtained. In addition, you can obtain the existing image files under the URL path in the backup storage.

Backup Storage Maintenance (Advanced)

ImageStore Maintenance

ImageStore Capacity Expansion

To expand the capacity of an ImageStore backup storage, follow these steps:

Disable your local backup storage.
Add a new large-capacity disk to a host, and format the partition. Assume the device name is /dev/sdc.
Create a new directory /new_volume, and run the command mount /dev/sdc1 /new_volume to mount this disk.
Run the command rsync -a /zstack_bs /new_volume/ to copy the existing disk files to the new disk.
Add content to /etc/fstab and bind the mount point of the physical disk to the /zstack_ps directory.
Restart the host, and use df -h /zstack_bs to check the space increment after expansion.
Restart the ZStack management node service.
Reconnect the host and continue to use ZStack.

ImageStore Maintenance

The steps for planned maintenance of an ImageStore backup storage are as follows:

Disable the ImageStore backup storage.
On the Backup Storage page, select the ImageStore backup storage, and select Clear Data from the Actions drop-down list to clean up the invalid data that was completely deleted in the backup storage to release the storage space.
After you clean up the data, enable the ImageStore backup storage to continue to use it.

Next Chapter:SAN Storage

Backup Storage

Backup Storage | Primary Storage

Notice

ImageStore

Backup Storage Maintenance (Advanced)

ImageStore Maintenance

ImageStore Capacity Expansion

ImageStore Maintenance

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