Backup data is stored in the form of objects on object storage, for Google Cloud these are objects stored in a GCS bucket.
Storage buckets are used as backup repositories. VBG supports tiering from standard to archive storage. There are some special considerations when using an object storage repository regarding sizing.
Because VBG compresses the source data before putting it in object storage in general the required space in object storage will be only ~50% of the source data. Compression depends heavily on the type and structure of source data and can vary.
|Average size of backup data||40% - 50%|
|Compression rate of backup data||50% - 60%|
Depending on the job type VBG stores different objects on GCS. The below table will show the object size per relevant type.
|Backup data (Standard)||1 MiB compressed (~512KiB)|
|Backup data (Archive)||512 MiB|
|Metadata||4KiB per GiB of VM source data|
The best performance is achieved on repositories created in regional storage buckets placed in the same region as source machine. When the bucket is far from the source vm instance we should consider slow network throughput between regions.
VBG comes with a built-in cost calculator. This uses publicly available price lists so may not reflect your exact cost should you have custom pricing or an enterprise agreement in place. Changes are automatically reflected within the policy and can be seen in the top header. Full details can be found on the cost estimation step.