Estimating costs with Azure Blob storage - Archive Tier

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Hi guys,

Try to estimate monthly costs for using Azure Blob Storage (Archive Tier) as a offsite backup.


In total we'll be looking to put 35TB up there, and I can see the starting cost of this is approximately €68 a month. We'll also be incrementally adding about 5GB a night to this blob container.

So I'll be configuring the container as cold Tier, but then I'll need to change the individual blob files to the  Archive tier. I can see from the pricing calculator that changing the Access tier of a blob is classed as a 'Write Operation', which is something we'll have to do for each blob.

Is adding new blobs, which we'll be doing on a nightly basis, also classed as a 'Write Operation' and is the uploading of one file/blob constitute one 'Write operation'??


Any help would be greatly appreciated!



3 Replies
best response

Hey Brendan,


A few things:


1. You can't configure Hot/Cool at the container level. This can only be done at the account or blob level. Archive can only be set at the blob level.

2. GPv2 accounts have replaced the Cool write fee with a 30 day early deletion fee (Blob Storage accounts still have Cool write fee and no Cool early deletion). If you plan on uploading and tiering immediately to Archive, its better to set the account tier to Hot.

3. Uploading a new blob using PutBlob is considered a write transaction. SetBlobTier when moving to a cooler tier is also considered a write transaction. So if you uploaded 1,000 blobs to a Hot account and then tiered them all the Archive, you would pay for 1,000 Hot write transactions and 1,000 Archive write transactions.




Thanks for that info Kumain,

This might be a stupid question, but just to confirm, does uploaded file equate to one blob?

Let's say I upload one file which is 10MB in size, and another which is 10KB in size. Each file is classed as one individual blob, and I'm charged for 1 write transaction on each? Ever though there's a huge size difference?


That's correct. Any object uploaded using PutBlob (regardless of size; max limit of 5TB) is 1 blob. Therefore any blob level operation such as SetBlobTier or GetBlob will be considered 1 transaction. When writing into Archive (SetBlobTier from Hot/Cool->Archive) you only pay for write transaction ($/10k txs) costs. However, when retrieving data from Archive (SetBlobTier from Archive->Hot/Cool), you will pay for both read transactions ($/10k txs) and data retrieval ($/GB). Archiving larger blobs is recommended to optimize transaction costs.