Hello Everybody,

Hope you all are safe and doing good.

In our last article we have discussed on the Overview Of Azure Storage and Database. Now onwards, we will continue with our new series and try to cover all services and features associated with this Azure storage and Database service in our up-coming articles. With this article, I am going to continue our journey with Azure Storage and Database Series. This article is completely based on the information from Microsoft document.

Previous Azure series :

1. Learn Basics Of Azure Networking In 60 Hours
2. Learn Basic Of Azure Active Directory And Azure Identity And Access Management
3. Azure DevOps – Learn at one place

If you have missed our previous articles on Azure Storage and Database Series, please check it in following links.

Part 1 – Overview Of Azure Storage and Database

Next Article : Part 3 – Azure Blob Service – Overview

Azure Storage Account :

Azure storage service is know for its well-designed architecture that take care of all types of small and big requirement, including complex organization’s requirement. With an SLA ranging from 99.9% – 99.99%, it is an easy choice for users looking for scalable, reliable, and effectively infinite space.

An Azure storage account is the heart of this service and also a cloud repository of data. An Azure storage account contains all of our Azure Storage data objects: blobs, files, queues, tables, and disks. The storage account provides a unique namespace for our Azure Storage data that is accessible from anywhere in the world over HTTP or HTTPS.

Azure Storage Features :

The following features apply to all types of Azure Storage services .

• Durability – As per the requirement, we can configure Azure storage data in such a way that, it can be replicated multiple times across regions. Redundancy ensuring that ,our storage account meets its availability and durability targets even.
• High Availability – With the above durable and storage redundant features, Azure storage services will automatically be highly available. 
• Scalability – Data is automatically scaled out and scaled in to meet the on demand requirement. Azure Storage provides a global namespace, which help to access data from anywhere any time.
• Security – Azure Storage relies on a Shared Key model for authentication security. The access can be further restricted through the use of a shared access signature (SAS). SAS is a token that can be appended to a URI, defining specific permissions for a specified period of time.
• Data protection – Azure Storage support data protection by allowing following configurations.
  • Point-in-time restore for containers
  • Soft delete for blobs
  • Soft delete for containers
  • Soft delete for file shares
  • Versioning for blobs for tracking purpose
  • Blob change feed for tracking purpose
• Easy To Connect - Azure Storage data can be accessible from anywhere in the world over http or https because of it’s unique namespace. Microsoft network routing option is recommended when configure traffic to travels from the source to its Azure endpoint. We can configure  network rules to restrict the access to our storage account. It supported by following connectivity methods.
  • Public endpoint (all networks)
  • Public endpoint (selected networks)
  • Private endpoint
  • All networks will be able to access this storage account
  • Use Secure transfer required option, to allow access to storage by secure connection (over https)

Naming Convention Of Storage Accounts :

When we create a new storage account, we must consider following few rules before naming our storage account.

• Storage account names must be between 3 and 24 characters in length.
• Storage account name may contain numbers and lowercase letters only.
• Storage account name must be unique within Azure. No two storage accounts can have the same name.

Azure Storage Redundancy :

We choose Azure storage because of it’s availability, durability and cost effective nature. It always stores multiple copies of our data in different places, so that it can protect our data from planned and unplanned events, including transient hardware failures, network or power outages, and massive natural disasters. 

Following factors helps to choose best redundancy option for our data, when planning for our requirement.

• How our data is replicated in the primary region.
• Whether your data is replicated to a secondary region that is geographically distant to the primary region, to protect against regional disasters
• Whether your application requires read access to the replicated data in the secondary region if the primary region becomes unavailable for any reason

In high-level Microsoft Azure redundancy options are divided into two based on their geographically distance.

1. Primary Region :
   • Locally redundant storage (LRS) : LRS is the lowest-cost redundancy option. In this option, Azure copies our data synchronously three times within a single physical location in the primary region. LRS protects our data against server rack and drive failures but not from a big disaster like fire and flood.
   • Zone-redundant storage (ZRS) :  ZRS copies our data synchronously across three Azure availability zones in the primary region. It’s availability ratio is more than LRS. The Archive tier is not currently supported for ZRS accounts.
2. Secondary Region :
   • Geo-redundant storage (GRS) : GRS copies our data synchronously three times within a single physical location in the primary region using LRS. It then copies our data asynchronously to a single physical location in the secondary region.
   • Geo-zone-redundant storage (GZRS) : GZRS copies our data synchronously across three Azure availability zones in the primary region using ZRS. It then copies our data asynchronously to a single physical location in the secondary region.

With GRS or GZRS, the data in the secondary region isn’t available for read or write access unless there is a failover to the secondary region. For read access to the secondary region, configure our storage account to use following options.

• Read-access geo-redundant storage (RA-GRS)
• Read-access geo-zone-redundant storage (RA-GZRS)

Storage Account Type/Kind :

Azure Storage offers several types of storage accounts with different features and each type of storage has it’s own pricing model. We should consider their features and pricing model before create a new storage account. Azure provides following storage accounts kinds/types,

• General-purpose v2 accounts: Basic storage account type for blobs, files, queues, and tables. Recommended for most scenarios using Azure Storage.
• General-purpose v1 accounts: Legacy account type for blobs, files, queues, and tables. Use general-purpose v2 accounts instead when possible.
• BlockBlobStorage accounts: Storage accounts with premium performance characteristics for block blobs and append blobs. Recommended for scenarios with high transactions rates, or scenarios that use smaller objects or require consistently low storage latency.
• FileStorage accounts: Files-only storage accounts with premium performance characteristics. Recommended for enterprise or high performance scale applications.
• BlobStorage accounts: Legacy Blob-only storage accounts. Use general-purpose v2 accounts instead when possible.

As per the Microsoft document, following table describes the types of storage accounts and their capabilities:

Storage account type	Supported services	Supported performance tiers	Supported access tiers	Replication options	Deployment model1	Encryption2
General-purpose V2	Blob, File, Queue, Table, Disk, and Data Lake Gen26	Standard, Premium5	Hot, Cool, Archive3	LRS, GRS, RA-GRS, ZRS, GZRS (preview), RA-GZRS (preview)4	Resource Manager	Encrypted
General-purpose V1	Blob, File, Queue, Table, and Disk	Standard, Premium5	N/A	LRS, GRS, RA-GRS	Resource Manager, Classic	Encrypted
BlockBlobStorage	Blob (block blobs and append blobs only)	Premium	N/A	LRS, ZRS4	Resource Manager	Encrypted
FileStorage	File only	Premium	N/A	LRS, ZRS4	Resource Manager	Encrypted
BlobStorage	Blob (block blobs and append blobs only)	Standard	Hot, Cool, Archive3	LRS, GRS, RA-GRS	Resource Manager	Encrypted

Storage Account Performance Tiers :

Performance tier helps to decide, how should, the storage account will store and return data from it’s storage. Azure storage offers following two different performance tiers:

• Standard Storage :
  • It optimized for high capacity and high throughput.
  • Standard Storage stores data on Hard Disk Drives (HDDs).
  • It is available to all regions.
  • Currently it supports only LRS, GRS, RA-GRS
  • Supported account types are General purpose v2, General purpose v1, Blob Storage
  • Standard performance supports different access tiers to store data in the most cost-effective manner. It’s designed for high capacity and high throughput on large data sets. It is useful in the following requirements.
    • Backup and disaster recovery datasets
    • Media content
    • Bulk data processing
• Premium Storage :
  • It optimized for high transaction rates and single-digit consistent storage latency.
  • Premium Storage stores data on the latest technology Solid State Drives (SSDs).
  • Specifically designed for Azure Virtual Machine workloads requiring consistent high performance and low latency.
  • It is available to selected regions only.
  • Currently it supports only LRS and ZRS
  • Supported account types are General purpose v2, General purpose v1, Block Blob Storage and file storage. Block Blob Storage and file storage are available in selected regions
  • Premium performance storage is ideal for requirement, that require fast and consistent response times like it is useful for the following workloads.
    • Interactive workloads
    • Analytics
    • Artificial intelligence/machine learning
    • Data transformation

Azure Blob Storage Access Tiers :

option is only for Blob Storage. This Azure storage feature allow us to store blob object data in the most cost-effective manner. Following are the available access tiers,

• Hot – Designed for storing data that is accessed frequently. The hot access tier has higher storage costs than cool and archive tiers, but the lowest access costs.
• Cool – Designed for storing data that is infrequently accessed and stored for at least 30 days. The cool access tier has lower storage costs and higher access costs compared to hot storage. 
• Archive – Designed for storing data that is rarely accessed and stored for at least 180 days with flexible latency requirements (on the order of hours).The archive access tier has the lowest storage cost. But it has higher data retrieval costs compared to other tires.

Archive access tier isn’t available at the storage account level. Only the Hot and Cool access tiers can be set at storage account level.

With the above information, I am concluding this article. I hope this is informative to you. Please let me know if I missed anything important or if my understanding is not up to the mark.

Next Article : Part 3 – Azure Blob Service – Overview

Keep reading, share your thoughts, experiences. Feel free to contact us to discuss more.

If you have any suggestion / feedback / doubt, you are most welcome. Stay tuned on Knowledge-Junction, will come up with more such articles.

Thanks for reading 🙂 .