Azure - Azure Storage (AZ)

Azure categories storage items in 4 categories

1. File    
   Used for files storage like text file, word file, pdf file, etc.
2. Blob 
   Used for the binary data store like an image file or library files etc.
3. Table
   Used to store key-value pairs
4. Queue
   Used to store queue messages. It works in a FIFO manner.

Account Kind of Storage

1. Storage (General Purpose v1)
   A general-purpose and used for legacy deployable (stuff build before 2014) that can be used to store file, blob, table and the queue.
2. StorageV2 (General Purpose v2)
   Recommended as it has the latest features and option to choose Access Tier as well
   A general-purpose and used to store file, blob, table and the queue.
3. Blob Storage
   Storage accounts with premium performance characteristics for block blobs and append blobs. Recommended for scenarios with high transaction rates, or scenarios that use smaller objects or require consistently low storage latency.

Replication or Data Redundancy

There are multiple options available for your requirements of Durability and High Availability

1. LRS(Locally Redundant Storage)
   Stores 3 copies of your data locally in a single physical location synchronously of the primary region.
   Cheapest option
   Not recommended for applications required high availability
2. ZRS(Zone-Redundant Storage)
   Copies your data synchronously across three Azure availability zones in the primary region. For applications requiring high availability. with economic rates.
   Durability: 99.99999999999 (11 9's)
3. GRS(Geo Redundant Storage)
   Copies 3 local copies synchronously using LRS of your data in the primary region and in a different geo-location asynchronously in the secondary region. you can think it as Geo Locally Redundant Storage.
   Durability: 99.999999999999 (12 9's)
4.  GZRS(Geo-Zone-Redundant Storage)
   Copies data in 3 Azure Availability zones synchronously in the primary region and in different Geo location asynchronously in the secondary region.
   Durability: 99.9999999999999999 (16 9's)
5. RA-GRS(Read Access Geo Redundant Access) Not supported currently
   Copies 3 local copies synchronously using LRS of your data in the primary region and in a different geo-location asynchronously in the secondary region. you can think it as Geo Locally Redundant Storage with reading access to secondary region data.
   Secondary region data is available to read in case your primary region unavailable.
6. RA-GZRS(Read Access Geo Zone Redundant Access) Not supported currently
   Copies data in 3 Azure Availability zones synchronously in the primary region and in different Geo location asynchronously in the secondary region. This replication avail read access to secondary region data. You can access secondary region data in case of primary unavailable.
   Durability: 99.9999999999999999 (16 9's)

Performance
This section basically define disk type which would use to store data

• Standard: Data backed into magnetic HDD drives, it offers cheap rates.  
• Premium: Data backed into solid-state drives SDD, provides high IOPS rate with 99.9% SLA.

Access Tier

• Hot: Can be used to store frequently accessed data. 
• Cool: Can be used if data access is infrequent. 
• Archive: Can be used to store data that accessed rarely. Only for blob.
  Can't be set on the storage level
  Can set at the blob level 

	Premium Performance	Hot tier	Cool tier	Archive tier
Availability	99.90%	99.90%	99%	Offline
Availability (RA-GRS reads)	N/A	99.99%	99.90%	Offline
Usage charges	Higher storage costs, lower access and transaction cost	Higher storage costs, lower access, and transaction costs	Lower storage costs, higher access, and transaction costs	Lowest storage costs, highest access, and transaction costs
Minimum object size	N/A	N/A	N/A	N/A
Minimum storage duration	N/A	N/A	30 days1	180 days
Latency (Time to first byte)	Single-digit milliseconds	milliseconds	milliseconds	hours2