How can we use Azure Cool Storage for Archiving data ?

Azure Cool Storage was introduced early this summer as a new Azure Storage Account tier type. The story is that before this time, the Azure Storage provides only one kind of Storage Accounts, which is for general purpose, and which includes two performance tiers, this makes using a Cloud Storage Account for storing daily data (Virtual Machines disks, File shares…) the same than archival and backup data.

A new type of Storage Accounts was introduced which brought two different tiers of Storage Accounts : Hot and Cool. The following picture shows the Azure Storage Account types :

SA-Types

This article explains how you can use the Azure Cool Storage tier for Archival purpose.

1- Scenarios proposal

1.1- Use StorSimple physical Array

Azure StorSipmle is a hybrid storage array which provides features to store data locally and on the cloud. StorSimple has many advantageous and offers a lot of interesting features like :

  • Tiering: As your data ages, automatically tier it and move it from solid-state disk to spinning hard drive to the cloud
  • Local volume: Ensure any primary data that you specify as local will stay on the physical StorSimple device
  • Cloud snapshot: Enable rapid movement of volume snapshots to the cloud to support integrated disaster, as well as dev/test and business analytic environments
  • Data deduplication: Deduplicate data inline to reduce your storage growth rates

The following capabilities will make the proposed design successful:

  • Azure Storsimple supports tiering on the Cloud –> Cold data will be moved from the local storage to the Cloud Storage
  • Azure StorSimple supports Azure Cool Storage Accounts as a Cloud Storage
  • Azure StorSimple can be exposed via iSCSI

The scenario is like the following :

  • A Cool Azure Storage Account (or more)  will be created an linked to the StorSimple.
  • A Volume (or more) will be created on the StorSimple
  • The volume (or volumes) will be presented to a Windows File Server
  • File Shares will be accessible for the Admins or the tools which will move data to be archived to these shares

–> Thanks to the Tiering feature, data which is Cold will be automatically tiered to Azure Storage Account. Because this data is not willing to change; we expect 100 % of cold data and hence tiered data

NB : Keep in mind the different StorSimple limits : https://azure.microsoft.com/en-us/documentation/articles/storsimple-limits/

1.2- Use StorSimple virtual array

If you don’t or are not planning to use the StorSimple physical array, you can use the StorSimple Virtual Array which was introduced early this year. The Virtual Array can be hosted by a Hyper-V or VMware virtualization platform. The StorSimple virtual array provides similar features than the physical array except the local storage, which should be provisioned from the virtualization platform storage. Keep in mind that the virtual Array provides less capacity than the physical one (Look to the first table on https://azure.microsoft.com/en-us/documentation/articles/storsimple-ova-overview/).

The Virtual Array has an additional feature compared to the physical one, which is the File Share feature. In fact, it can exposes directly SMB shares to the users.

The design is like the following :

Variant 1

  • A Cool Azure Storage Account (or more)  will be created an linked to the StorSimple.
  • A Volume (or more) will be created on the StorSimple
  • The volume (or volumes) will be presented to a Windows File Server
  • File Shares will be accessible for the Admins or the tools which will move data to be archived to these shares

Variant 2

  • A Cool Azure Storage Account (or more)  will be created an linked to the StorSimple
  • A file share (or more) will be created
  • File Shares will be accessible for the Admins or the tools which will move data to be archived to these shares

–> Thanks to the Tiering feature, data which is Cold will be automatically tiered to Azure Storage Account. Because this data is not willing to change, we expect 100 % of cold data and hence tiered data

1.3- Use Microsoft Azure Storage Explorer

Microsoft Azure Storage Explorer is a tool developed and maintained by Microsoft which allow managing and making different operations on the Azure Storage accounts.

The tool can be downloaded here : http://storageexplorer.com/

NB : Please, do not confuse Microsoft Azure Storage Explorer and Azure Storage Explorer. This latter is an open sourced project which is not very well maintained (But was here first)

The scenario is like the following :

  • Install MASE on a server (We recommend a dedicated server)
  • Use AZcopy (The MASE Command line) to copy the data to be archived to the Azure Cool Storage Account. You can use the Storage Explorer UI either. The AZCopy tool is good if you want to schedule data movement or create scripts.
  • Use MASE to explorer and download the Azure Storage Account data

NB: MASE does not provide mounting a Storage Account Container, and managing the content (Browser, Copy, Delete…) via a drive letter.

1.4- Use a third party tool

There are different Third Party Tools which allow managing and accessing Azure Storage Accounts. The difference regarding MASE is that these tools allow mounting the Storage Account containers to virtual drives. This way they can be accessed directly via the windows explorer.

The scenario is like the following :

  • Install the tool on a server (We recommend a dedicated server)
  • Attach a Cool Azure Storage Account using the tool and create a mount point (Or a virtual drive)
  • Admins can move data to be archived directly to the mount points

The following are two tools which can be used for this purpose:

2- Scenarios Comparison

Scenario

+

My Rating

StorSimple Physical Array Best capacity and performance Expensive or needs minimum credit if purchased under EA

No SMB file shares support like the SVA

Use it if you already have a physical Storsimple

Enterprise solution

StorSimple Virtual Array Support SMB File Shares (Windows File Share + Share Permissions)

Free

Needs a virtualization platform and a local storage capacity  (10 % of the total storage)

Limited capacity if exposed via iSCSI (5 TB per Volume)

Use it if you don’t have a physical Storsimple or you don’t want to deploy a File Server

Enterprise solution

Microsoft Azure Storage Explorer Free

Simple to use

Storage Accounts are only exposed via the tool UI and command line Personal or occasional use
Third Party Tools Simple to use May not be scalable for Free editions Personal or occasional use

3- Azure cool storage costs

Assumptions :

  • I do not count blobs operations which are billed too. We estimate that the cost of these operations will not pring impact on the total cost. In addition, it’s not predictable
  • I assume that there is no change on the already written data (archived data does not change over time). The change will inquire write costs
  • I’m using Public prices North Europe region (Euro)
  • Do not forget that the pricing is per Month for the Storage and per Operation (per GB) for Write, change and retrieval
 

Storage per Month

Data write per Operation

Data retrieval per operation

LRS

GRS

LRS

GRS

LRS/GRS + outbound data transfers

1 GB

0.0084 €

0.0169 €

0,0021 €

0,0042 €

0,0818 € = 0,0084 + 0.0734

10 GB

0.084 €

0.169 €

0,021 €

0,042 €

0,818 € = 0,084 + 0.734

100 GB

0.84 €

1,69 €

0,21 €

0,42 €

8,18 € = 0,84 + 7,34

1 TB

8,4 €

16,9 €

2,1 €

4,2 €

81,8 € = 8,4 + 73,4

Costs example with a Cool storage account in GRS redundancy:

  • If we store 1 TB of data we’ll pay: 16,9 € / month + 4,2 € once
  • If we download 1 GB we’ll pay: 0.0818 € once
  • If we download 100 GB we’ll pay: 8,18 € once
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