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What is a block blob in azure and how is it different from object storage

Anuj Jain 71 Reputation points
2022-10-01T15:21:44.54+00:00

I understand what object storage, block storage, and file storage are. But I am having trouble understanding the concept of a block blob in azure and how it differs from a blob in object storage. Is it that Azure does not have object storage, and though it calls it containers (in a storage account), it is an implementation of block storage to store blobs? To add to this confusion is the option in the premium storage account to select a "Block" blob and a "Page" blob.
I have spent quite a lot of time trying to understand the fundamental of a "Block Blob" vs. "Blob" in object storage.
Thanks for your help in advance.

Azure Storage
Azure Storage

Globally unique resources that provide access to data management services and serve as the parent namespace for the services.

Azure Blob Storage
Azure Blob Storage

An Azure service that stores unstructured data in the cloud as blobs.

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  1. Graham Moor 81 Reputation points
    2022-10-01T18:15:37.103+00:00

    1 person found this answer helpful.
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  2. Anuj Jain 71 Reputation points
    2022-10-01T19:33:36.583+00:00
    • Thank Graham. It looks like I might be, in fact. I understand the term blob as a generic binary large object.
    • Perhaps the term "block" here is different and not the same as the on-prem block storage devices for high transactional databases etc.
    • I was under the impression that block storage and object storage are mutually exclusive, wherein object storage can be on cheap/generic hardware while block storage on very fast expensive disks. Furthermore, the way data is stored in blocks is different from how it is stored in an object store; hence the retrieval/writing performance differs.
      • I just searched and someone had posted a similar message asking a similar question. ([link][1])
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  3. Graham Moor 81 Reputation points
    2022-10-01T18:56:05.167+00:00

    I think you may be confusing the terminology

    So a blob is a storage term (sure you know binary large object), the word before defines the implementation
    -block is used more for large data loads - so large writes
    -page is optimised for read write
    -append uses blocks but for additions (appends)

    The cost of storage (largely) is based on the tech used, and the storage tier (archive / cool / hot). So if the storage is HDD, the cost will generally be lower, if premium SSD, the costs higher.

    Block blobs require Premium SSD, so do have a higher cost.

    https://learn.microsoft.com/en-us/azure/storage/common/storage-account-create?tabs=azure-portal

    246663-image.png

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  4. Anuj Jain 71 Reputation points
    2022-10-01T18:22:57.413+00:00

    Thanks, Graham, but it is not clear to me.
    For example, the first link says, "blob storage is Microsoft's object storage solution for the cloud." It also talks about "blocks.".
    My understanding has been that block storage is expensive, and object storage is cheap (in general).
    Hence the use of the terminology "Block" with "blob storage," which is "Microsoft's object storage solution for the cloud," is confusing to me.

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