CODEWITHSUNDEEP
azureazure-storagesnapshot
user1154422
user1154422

Reputation: 656

Does an Azure Snapshot of a Page Blob create a copy?

To Developers,

What if scenario: I have a 1 TB Page Blob and I make 10 snapshots of it and mount the 10 snapshots to VM's. Assuming the base Page Blob does not get modified, do I have ~10 TB or ~1 TB of storage? I would prefer to have the 10 VM's have their own copy.

Is this the same behavior for Standard (mechanical disks) and Premium (ssd's) Storage?

My understanding from conversations with Microsoft is that Standard storage does not perform a copy and Premium does but could not find it in the documentation.

Thanks, Marc

Upvotes: 1

Views: 324

Answers (1)

David Makogon
David Makogon

Reputation: 71030

First: Snapshots are read-only, so your initial snapshots are not immediately usable with a vm - you'd need to make a copy to a regular blob.

Second: When you first create a snapshot, the storage is very minimal. But, over time, as the base blob changes, the snapshot will grow in size, to reflect the difference. So initially your 10 snapshots will barely register on your consumption. But as you keep writing to your original vhd, you'll see your snapshots grow (eventually upwards of 1TB each).

Knowing this, you'll want to manage your snapshots carefully (e.g. don't create unlimited hourly snapshots without ever deleting any).

EDIT: for managed disks, the behavior is different. With managed disks, a disk gets fully allocated up front, and the snapshot is full-size as well.

Same thing with premium storage (whether managed or not): the disk is fully allocated up front.

Upvotes: 2

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