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SoftNAS can leverage both block storage (such as the varieties of SSD and HDD disks available under General Purpose storage accounts on Azure) and object storage such as Azure Blob Hot or Cool storage. This flexibility is one of the key features of SoftNAS. It can, however, introduce some complexities when determining your requirements. As performance is based not only on the instance size selected but also the storage characteristics, leveraging different types of storage in the same solution will affect your performance.

To determine what this effect might be, we must first understand the individual performance characteristics of each storage type.  

There are numerous distinctions and abstractions in Azure storage which can confuse the layperson in choosing the right storage option for them. However, when using SoftNAS, the simplest way to determine the storage option for you is based on two factors – the storage account which determines the type of storage available, and the storage type itself, block or object storage.  The below information will help you understand Azure block and object storage as it relates to your SoftNAS Instance.

Azure Block Storage

Block storage provides fixed-size raw storage capacity. Each storage volume can be treated as an independent disk drive, and is only accessible when attached to an OS. It is typically formatted with a file system, such as FAT32, NTFS, EXT3, or EXT4.

The type of storage provided is determined by the storage account. Block Storage, or General Purpose, is further divided by account type, Standard or Premium.  (Blob Storage is limited to one category, Standard.)

  • Standard Storage Accounts
    Standard Storage Accounts are based on magnetic drives and are an affordable solution for applications or other use cases in which the underlying data is accessed infrequently.
  • Premium Storage Accounts
    Premium Storage is backed by solid state drives, and offers consistent, low latency performance. It is the recommended option for any application in which data must be retrieved quickly and often.

Standard Storage Accounts provide disks with a single performance metric, with per disk limits. 


Standard Storage Account

Max Disk Size

1023 GB

Max 8K IOPS per disk

Up to 500

Max Bandwidth per disk

Up to 60 MB/s

With Premium Storage, on the other hand, you are offered three disk types, corresponding to 3 different disk sizes. When creating a disk for your SoftNAS instance using a Premium Storage account, you will only be able to specify one of the following sizes: 128GB, 512GB, and 1024GB. Whether you create the disk from the Azure portal, or type the disk size within the Add Device wizard in the SoftNAS UI, you are selecting the corresponding disk type, with the performance characteristics listed in the table below.  

 


Premium Storage Account

P10

P20

P30

Max Disk Size

128 GB 

512 GB

1024GB

IOPS per disk

500

2300

5000

Throughput per disk

100 MB/s

150 MB/s

200 MB/s



If adding storage from the SoftNAS StorageCenter™ interface, via Add Disk Device (as described in Adding Storage via the SoftNAS UI) you are provided two options:

  • Cloud Disk Extender
  • Microsoft Cloud Disk Extender

In the SoftNAS UI, the latter selection is for block storage, and will create block storage within your SoftNAS Instance. 

As it is creating block storage, it is leveraging a block storage account. This block storage account provides what is termed General Purpose storage. This is determined in one of the important decisions made when creating a storage account: Account Kind.

 

When creating your SoftNAS Instance, you MUST be aware of the above account types and the distinctions between them. The type of storage account that can be provisioned for your instance is determined by a selection made at instance creation -VM Disk type


 

SSD will ensure your SoftNAS Instance is provisioned for Premium storage accounts, and HDD will enable your instance to use Standard storage accounts


Azure Blob Storage: Hot and Cool

If deciding to add Azure object storage (otherwise known as Blob storage), you will need to have a Blob storage account set up, or you will not be able to call upon the storage within the SoftNAS UI. When creating your Blob Storage account, you will also have another decision to make - whether you will leverage hot or cool storage for Azure. SoftNAS offers full support for both options:

  • Azure Cool Storage - Object storage that allows economical safe-keeping of less frequently accessed file data.  
  • Azure Hot Storage - Object storage that optimizes frequently accessed stored data to enable continuous IO.

Note: You cannot mix hot and cool storage disks in a RAID configured pool. A decision must be made on storage type for each pool. As storage type is determined at the blob storage account level, you must be aware of the type of account created. SoftNAS recommends labelling them with Hot or Cool in the names to avoid confusion.

When creating your Azure blob account, you will see an option to determine the 'Access tier' with two available options, Hot and Cool. This setting determines what type of blob storage the account in question will provide. If Hot, this storage account will only provide Hot storage to your instance. If creating a separate pool of Cool disks, another blob storage account will need to be provided.

In a given pool, you can add any number of azure blob storage disks, by first creating blob storage accounts. It is recommended to name them in sequence with clues as to which type of storage they provide.

 

Never mix blob storage accounts within the same pool. SoftNAS will alert you should this occur accidentally.