Object Storage
Backup data is stored in the form of objects on object storage, in the case of Azure these are blobs stored in a storage account.
Azure Blob storage accounts are used as backup repositories. VBAZ supports hot, cool, and archive storage tiers. There are some special considerations when using an object storage repository regarding sizing.
Object Storage Data Size
Because VBAZ 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 of course depends heavily on the type and structure of source data and can vary.
| Item | Data size |
|---|---|
| Average size of backup data in object storage | 40% - 50% |
| Compression rate of backup data | 50% - 60% |
Object Sizes
Depending on the job type VBAZ stores different objects on Azure Blob. The below table will show the object size per relevant type.
| Object type | Size |
|---|---|
| Backup data (hot and cool tiers) | 1 MiB compressed (~512KiB) |
| Backup data (archive tier) | 512 MiB |
| Metadata | 4KiB per GiB of VM source data |
Storage Account Limits
Storage accounts have throughput limits that vary per region. It is recommended to configure multiple repositories for a single VBAZ deployment, or even, in some cases, one per policy. This changes regularly, as of writing these limits are:
| Resource | Limit |
|---|---|
| Default max request rate per storage account | 20K IOPS (remember a ~512KiB block size) |
| Default max write speed in large regions | 60Gbps |
| Default max write speed in other regions | 25Gbps |
| Default max write speed for legacy storage accounts | 10Gbps |
Cost Estimation
VBAZ 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.