Azure Backup – Data Plane – Access Tiers

The Data Plane in Azure Backup refers to the actual storage and retrieval of backup data.

When you back up data to Azure, it is stored in a specific storage type, and Azure Backup gives you flexibility in how that data is managed based on access needs, performance requirements, and cost constraints.

The Access Tiers in Azure Backup help optimize storage costs by offering different storage levels based on how often you expect to access your backup data.

Azure Backup integrates with Azure Storage and provides Access Tiers for backup data stored in Recovery Services Vaults.

The choice of Access Tier influences the cost of storing and retrieving backup data, so it is important to understand the different tiers and how they work.

What Are Access Tiers in Azure Backup?

Access Tiers are storage options that categorize how frequently data is accessed, and they determine the cost structure of storing and retrieving backup data.

These tiers are designed to meet different needs, from high-availability scenarios to infrequent access cases, helping you manage costs effectively while ensuring appropriate data availability.

In the context of Azure Backup, there are three primary Access Tiers:

1. Hot (for frequently accessed data)

2. Cool (for infrequently accessed data)

3. Archive (for long-term, rarely accessed data)

Each tier is designed for specific use cases, depending on how often you need to access the backup data and your cost considerations.

Hot Access Tier

The Hot Access Tier is designed for data that is accessed frequently.

It offers high availability and low latency, which makes it ideal for workloads that require regular and fast access to backup data.

If your backup data needs to be restored quickly or accessed for frequent operations, the Hot Tier is the most appropriate choice.

Key Characteristics

1. Frequent Access: Best suited for backup data that is accessed often (e.g., daily backups, frequently restored backups).

2. High Performance: Optimized for low-latency and high throughput operations, which is essential for restoring data quickly when required.

3. Cost: Storage costs are higher compared to the Cool and Archive tiers because the system is optimized for fast access to data.

4. Retrieval Costs: Data retrieval from the Hot tier is cheaper and faster compared to other tiers.

Typical Use Cases

1. Backup data for Azure VMs and SQL databases that need to be restored often.

2. Applications or workloads with a high likelihood of recovery in a short amount of time.

3. Daily backups that are expected to be restored periodically.

Cool Access Tier

The Cool Access Tier is designed for data that is infrequently accessed but still needs to be stored for a longer duration (e.g., for compliance or regulatory reasons).

This tier is typically used for backup data that is not accessed often but must be retained for extended periods.

Key Characteristics

1. Infrequent Access: Designed for backup data that is not frequently accessed but must remain available for longer periods.

2. Lower Storage Costs: Storage costs are lower than the Hot tier but higher than the Archive tier, making it more affordable for long-term retention of data that is rarely accessed.

3. Retrieval Costs: Retrieval from the Cool tier is more expensive than the Hot tier, so it’s ideal for scenarios where data is seldom needed but must be kept accessible when required.

4. Minimum Retention Period: Data stored in the Cool tier must be kept for at least 30 days. If data is deleted or moved before this period, an early deletion charge applies.

Typical Use Cases

1. Backup data that needs to be retained for regulatory or compliance reasons but is not expected to be accessed frequently.

2. Data from Azure VMs, files, and SQL databases that are rarely restored but must be available in case of disaster recovery scenarios or compliance audits.

3. Monthly or quarterly backup data that is not needed immediately but still needs to be retained.

Archive Access Tier

The Archive Access Tier is designed for long-term storage of data that is rarely accessed.

This is the most cost-effective option for retaining large amounts of backup data that is infrequently needed and is stored for regulatory, legal, or compliance purposes.

The Archive tier is often used for cold storage scenarios.

Key Characteristics

1. Long-Term Storage: Designed for backup data that is expected to be accessed very infrequently (e.g., once a year or never).

2. Lowest Storage Costs: Offers the lowest cost for storing backup data, but with a higher cost for retrieval.

3. High Retrieval Latency: Restoring data from the Archive tier can take several hours, so it’s suitable for scenarios where retrieval speed is not a critical factor.

4. Retrieval Costs: Retrieval costs from the Archive tier are higher than both the Hot and Cool tiers. There is also a fee for moving data in and out of this tier.

5. Minimum Retention Period: Data stored in the Archive tier must be retained for a minimum of 180 days before it can be deleted.

Typical Use Cases

1. Long-term retention of backup data that is required for compliance or regulatory reasons but is unlikely to be accessed.

2. Backup data that will only be needed for audit, legal, or disaster recovery purposes far in the future.

3. Offsite data archives, like long-term storage of older VM backups or inactive SQL database backups.

Azure Backup and Access Tiers

Azure Backup allows you to take advantage of different access tiers to manage the cost of backup storage.

When you set up Azure Backup, you typically have the option to choose which Access Tier is used for the backup data in the Recovery Services Vault.

The choice of tier depends on how often you expect to access the data and your cost preferences.

Here’s how Azure Backup works with these tiers:

Integration with Recovery Services Vault

1. When you configure backup for an item (e.g., an Azure VM, SQL Database, Azure Files, etc.), Azure Backup stores the backup data in the Recovery Services Vault.

2. You can choose which Storage Redundancy option to use (e.g., Locally Redundant Storage (LRS) or Geo-Redundant Storage (GRS)), and then select an Access Tier (Hot, Cool, or Archive) based on your needs.

3. Azure Backup provides policy-driven backup where you can define retention rules for backup data. Depending on your policy, you can migrate the backup data between different tiers (e.g., from Hot to Cool) as your access needs change.

Backup Data Lifecycle Management

Azure Backup helps you manage the backup data lifecycle with policies that can automate the movement of backup data between tiers over time.

For example:

1. Initial Backup to Hot Tier: You can start by backing up your data to the Hot tier if the data needs to be accessed frequently, or if you expect to restore it shortly after backup.

2. Archiving Data: Over time, as the data becomes less frequently accessed, you can move older backup data to the Cool tier or Archive tier for long-term storage.

3. Automated Data Movement: Azure Backup can automatically manage this process as part of its Retention Policies. For example, older backup data can be moved to the Archive tier once the retention period for more frequent backups expires.

Cost Considerations with Access Tiers

The choice of Access Tier significantly affects the cost of backup storage and retrieval.

Here’s a comparison of how each tier impacts costs:

Storage Costs

1. Hot Tier: Higher cost for storage since it’s designed for frequent access and low latency.

2. Cool Tier: Moderate cost for storage, suited for data that is infrequently accessed but needs to be kept available.

3. Archive Tier: Lowest cost for long-term storage, suited for infrequent access or compliance requirements.

Retrieval Costs

1. Hot Tier: Lowest cost for retrieving data. Quick access is guaranteed.

2. Cool Tier: Higher retrieval costs compared to Hot, but still affordable for infrequent access.

3. Archive Tier: Highest retrieval costs and retrieval times. Data retrieval takes hours and should be used only for long-term retention with minimal access.

Data Access Frequency

1. Hot: Suitable for frequent access (e.g., daily or weekly backups).

2. Cool: Suitable for occasional access (e.g., monthly backups).

3. Archive: Suitable for rare access (e.g., yearly access, or never unless required by law or regulations).

Summary

Access Tiers in Azure Backup provide a flexible way to manage the cost of storing backup data while meeting business needs for data accessibility.

By understanding and selecting the right Access Tier for your backup data, you can optimize both cost and performance based on how frequently you need to access your data:

1. Hot Tier: Ideal for frequently accessed backups that require low-latency and fast recovery.

2. Cool Tier: Suitable for infrequently accessed data with a need for lower storage costs, such as for compliance.

3. Archive Tier: Best for long-term storage of rarely accessed backup data at the lowest cost.

By using these access tiers strategically, you can ensure that your backup strategy is both cost-effective and aligned with your data access needs.