I was tasked with optimizing the storage cost of a container in my storage account, which holds approximately 50-TB of data in the cool tier. The challenge was to change the access tier from "Cool Tier" to "Cold Tier" for millions of blobs across thousands of folders. Azure portal allows access tier modification from Hot/Cool to cold tier only on the blob level, making it impractical to individually change tiers for 78 million blobs.
To save time, we attempted to modify the access tier on the container or folder level using Azure Storage Explorer, but the process was very slow and crashed multiple times and restarted after each 1 or 2 million successful attempts.
We then discovered an alternative approach using the AzCopy Props command, which effectively and quickly changed the access tier of all 78 million cool tier blobs to Cold Tier.
However, upon reviewing cost management, we observed a additional $3000 charge for write operations on the same storage account where we changed the access tier.
My Question❓
Does Microsoft Azure consider changing the access tier as a write operation according to their documentation?
If Not, what could be the reason for this cost, given that no data has been written to the storage account for several months?
If Yes, it is indeed a write operation, what alternatives are available for smoothly performing bulk access tier changes without interruptions or crashes, unlike our experience with Storage Explorer? Thank You!
We have to optimize Azure Storage cost by changing Access tier Cold Tier.
Yes, based on the pricing page, changing blob tier is considered as a write operation.