In this post, I’ll explain what Microsoft’s General Purpose v2 (GPv2) storage account is and how this is related to the general availability of tiered blob storage.
Tiered Blob Storage
Azure blob storage is very affordable. It costs just $0.0208 per PG per month (RRP East US region, LRS) to store a file in Azure storage. But if you are working for a company that needs to store lots of data for long periods of time, then that low cost might still feel high. Many organizations have data that must be kept around but isn’t used that frequently or at all.
Microsoft kicked off the Summer of 2016 by launching hot and cool storage in Azure. A new kind of storage account called the blob storage account (blobs only), enabled you to define a default tier for any blobs that were stored in the account. And then you could change the tier of that storage. The two tiers were:
- Hot: Blob storage was at the highest rate but access was at the cheapest rate. Files/blobs that are frequently accessed should be stored here.
- Cool: Blob storage was more affordable but access rates were higher. Less frequently access files/blobs should be stored here.
Storage became cheaper but it could be even more affordable. AWS Glacier storage offered a lower-cost service where data is kept in an offline media with longer read latency (hours instead of milliseconds).
Now Microsoft has made a new tier of storage available; We now have hot, cool, and archive tiers of blob storage. The new archive tier offers:
- A cheaper form of storage, costing approximately $0.002 per GB per month … or approximately $2.05 per TB per month!
- The blobs are kept offline with a read latency of up to 15 hours.
Data that is moved to the archive tier cannot be accessed directly; instead, you have to “rehydrate” the files/blobs to either a cool or a hot tier, where you can access it. Note that Azure billing will penalize you for rehydrating a file if it was in the archive tier for less than 180 days (180 – actual days).
Today, the tiering process is not policy based but this might come in the future. You can move blobs manually or programmatically.
General Purpose v2 (GPv2) Storage Accounts
Before today, we had two kinds of storage account:
- General Purpose (v1 or GPv1) storage account: This supports blob, Azure Files, message, queues, and un-managed disks (page blobs), and has low-cost access rates.
- Blob storage accounts: These blob-only storage accounts offer support for blob tiering, initially hot or cool, but now hot, cool, or archive support.
Microsoft is attempting (more later) to simplify this by providing us with a single storage account that supports all storage types and blob tiering. The GPv2 storage account takes everything from the GPv1 storage account and adds hot/cool/archive blob tiers.
In Microsoft’s announcement, there was a disclaimer about GPv2 storage accounts:
GPv2 accounts have a different pricing model than GPv1 accounts, and customers should review it prior to using GPv2 as it may change their bill.
When you dig into the new charges, the cost of doing things like blob write operations (per 10,000) in the hot tier has increased from $0.0004 in GPv1 to $0.05 in GPv2. That’s an increase of x 125, which means that your write charges might go, for example, from $1/month to $125/month!
As a result, teams such as Azure Site Recovery are recommending that customers stick with GPv1 storage accounts. I cannot blame them. While I’m all for adding features such as blob tiering and the archive tier, I’m concerned about the apparent x125 increase in costs for storage access.
Be careful! The GPv2 is the new default in the Azure Portal when creating a new storage account. Don’t fall into the new increased charges if you want to avoid them by continuing to use GPv1.