Tag Archives: Azure Storage

Enterprise data life cycle management using Azure Storage

Storage is one critical component in the Enterprise world. Managing data and its life cycle is a crucial element in many aspects, such as optimizing storage usage, managing cost, adhering to the compliance & archival requirements, security and etc.

Primarily data is stored in database systems (relational and non-relational sources) and as files (includes data lake and blobs), addition to that, data resides in other systems like email servers, document systems, file shares, event and messaging pipes, logs, caching systems and etc.

Laying out a comprehensive data strategy for an organization is a complex process. However, in most cases the data lands in a flat storage as the final tail grade destination. So managing the storage and life cycle management is an important task.

Let’s consider a simple backup storage scenario.

A relational data source assume a SQL Server VM, has following backup requirement.

Frequency	Backup Type	# backups	Access Frequency
4 hours	Incremental	42	Medium
Daily	Full	30	High
Weekly	Full	12	High
Monthly	Full	12	Low
Semi-Annual	Full	6	Very Low
Year	Full	8	Very Low

At any given time (assuming a complete 8 years span) there should be 110 backups maintained. Those 110 backups, should be kept in the right storage based on the access frequency and retention period.

Azure Storage provides access tiers which helps us to determine and auto manage the storage requirements. Azure storage (storage generation v2) let us define life cycle policies at blob level.

The below diagram depicts this

storage tiers

As shown in illustration, there are three access tiers, hot, cool and archive. Hot and Cool access tiers can be set at the storage account level, and archive tier is set at the individual blob level.

We can define life cycle policies, where the blob movement between tiers from hot to archive and all the way to deletion can be automated to match our requirements.

Sample life cycle policy of a blob.

	{
	"rules": [
	"enabled": true,
	"name": "yearly backup rule",
	"type": "Lifecycle",
	"definition": {
	"actions": {
	"baseBlob": {
	"tierToCool": {
	"daysAfterModificationGreaterThan": 30
	},
	"tierToArchive": {
	"daysAfterModificationGreaterThan": 60
	},
	"delete": {
	"daysAfterModificationGreaterThan": 370
	}
	}
	},
	"filters": {
	"blobTypes": [
	"blockBlob"
	],
	"prefixMatch": [
	"backups/annual"
	]
	}
	}
	}
	]
	}

view raw

blob life cycle policy.json

hosted with ❤ by GitHub

You can see, under the filters section, we can specify the path, where the rule should be applied. In this way we can have more than one rule for a storage account addressing different paths.

Out of different options in the Azure storage, we should have a standard general purpose V2 storage, in order to get the access tier capability. Standard blob also has the access tier capability. Standard storage is powered by magnetic disks.

Whereas, Premium storage is powered by SSDs but does not offer access tier. Premium storage is intended for the page blobs, like virtual machine disks. Addition to the page blobs, we can use premium storage as blob storage and file shares.

At summary this is the high level view of the available options in Azure Storage.

stroage summary view

Dev Day 2015 FB app – powered by Azure Storage

An FB app was around during the Dev Day 2015 season, which generates a picture merging dev day logo along with user’s current profile picture and posts that in his/her facebook timeline. The user who generarted more pictures announced as the winner.

Anuradha presenting the FREE ticket to the Winner.

There were 478 unique users generated 1023 images. These numbers aren’t that stagerring but let’s see how this app was modeled.

App used Azure Blob storage and Table storage. Blob storage was used to store the merged images of the users.

In the Azure Blob storage there were two containers one is public and the other one is private. The app specific images were stored in the private container including the dev day logo. The generated images were kept in the public container so easy to post them to Facebook using the public URL.

Privacy policy was aligned to cater the behavior of keeping the merged images in a public repository. “according to app privacy policy – the merged images are considered as processed content of the app and can be used outside the scope of the app itself. The app did not store the raw profile pictures anywhere”

Table storage was used to store the information of participants, and initial rule was share the picture and one user will be selected in random as a winner, so the design was like this.

There was only single partition and no much worry on that. But Facebook User Id had been used as the RowKey making that even if a user generates the image more than one time, there will be single entry in the table. As a lazy programmer i just used a single Upsert opertaion to write data to this table.

But soon after launching the app I noticed the usage pattern is significanly different and same users had been generating more than one image, I tracked this using the Table Storage TimeStamp column and also I had another columnd to track the last updated time.

To make the competition fair and increase the traffice, I redesigned it by announcing the new rule, saying the person who generates more images will be the winner. Changed the RowKey to a GUID and adding another Id column to track users.

At the end of the competition a simple group by Id query with the count revealed the winner.

Speacail thanks to @Madhawee for helping in the UI of the app.

A portion of the collage generated from first 100 photos generated by the app. (Images are posted here with the privacy policy acceptance by the users, that merged images could be used externally outside the scope of the app itself)

Click to enlarge.

Windows Azure Scheduler

Windows Azure Scheduler is one of the new feature additions to Windows Azure. This is a cloud based scheduler service which analogous to the Task Scheduler.

Login to you Windows Azure Management Portal, If you do not see the Scheduler tab in the left hand side either you didn’t activate it or the feature is not available in your subscription. If you haven’t activated you can activate it and continue the following; if you don’t have the access to the Scheduler in your subscription don’t worry I’ve provided the screenshots. I always include the screenshots much as possible when writing Windows Azure posts just to explain the features as they are, in case you do not have access to them.

Click on the CREATE SCHEDULER JOB and you will get this nice Azure pop menu

Click CUSTOM CREATE, Select your region and enter a name for your Job Collection. (Note that at the top it says ‘You are creating a Standard Job Collection’ you can change this in the scale tab)

As of now we have Job actions for HTTP, HTTPS and Storage Queue. I used the Storage Queue action. Once you select your storage account and Queue name you should give the permissions to Scheduler Job to access the Queue storage. This can be achieved very easily by generating a Shared Access Signature (SAS) for the Queue.

Next the you can configure the job timing schedules. It has more options; I have selected to run the job every 5 minutes till a specific date starting immediately after the job has been provisioned.

And that’s it. This is the sample message posted by the Job in the Queue.

<?xml version="1.0" encoding="utf-16"?>
<StorageQueueMessage xmlns:xsd="http://www.w3.org/2001/XMLSchema"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <ExecutionTag>4cf887834d7cd1466f549b2ac2fb56c8</ExecutionTag>
  <ClientRequestId>d36f421b-9338-4e4f-ad89-69dd490530a1</ClientRequestId>
  <ExpectedExecutionTime>2014-04-04T06:15:10</ExpectedExecutionTime>
  <SchedulerJobId>msgQ</SchedulerJobId>
  <SchedulerJobCollectionId>testjob</SchedulerJobCollectionId>
  <Region>Southeast Asia</Region>
  <Message />
</StorageQueueMessage>

You can see the Message tag is empty since I didn’t put any messages. You have the complete control in editing the Job you created.

Uploading a file to Azure Blob

Windows Azure storage provides flexible storage services. Blob storage is one of them which is used to store binary large objects.

Windows Azure blob has the concepts of containers (which you can think like partitions of a disk). Containers are either private or public.

Private containers are only accessible to the user and application developer with proper storage access keys. Public containers are accessible to all. So just by URL you can access a file stored in the public container.

You can use the Azure Storage Explorer to create and manipulate your Azure storage. It is a handy tool available for free from codeplex. Download link : http://azurestorageexplorer.codeplex.com/

The below code sample demonstrates how you can upload a file to a private container named ‘privatecontainer’ in Windows Azure.

private void UploadFileToPrivateContainer()
{
    // get the storage (blob) connection string from the config file
    var storageAccount = Microsoft.WindowsAzure.Storage.CloudStorageAccount.Parse
        (CloudConfigurationManager.GetSetting("StorageConnectionString"));
  
    // creates a blob client
    CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient();
  
    // creates a container :: container name should be small otherwise you'll get Error 400 Bad Request Error.
    CloudBlobContainer container = blobClient.GetContainerReference("privatecontainer");
    container.CreateIfNotExists();
  
    // gets the physicall file path to be uploaded from ASP.NET FileUpload content.
    string path = FileUpload1.FileName;
    
    // creating a blockBlob, if a block blob exists witht the same name then it will be replaced.
    CloudBlockBlob blockBlob = container.GetBlockBlobReference(Path.GetFileName(path));
  
    var stream = FileUpload1.FileContent;
  
    // uploads the stream.
    blockBlob.UploadFromStream(stream);
  
    stream.Close();
  
    Label1.Text = "Upload Success";
}

I used the Azure Storage Explorer to create the container, you can create it using the code as well.

In order to run the above sample you should have Azure SDK installed and use Nuget Package manager to install the Windows Azure Storage assemblies.

Here’s the code for transfer a file from a private container to public container. Azure storage SDK doesn’t have an operation for move. So here we copy the file to the public container by downloading and re uploading it and deleting the file from the private container.

protected void BtnMove_Click(object sender, EventArgs e)
{
    var storageAccount = Microsoft.WindowsAzure.Storage.CloudStorageAccount.Parse(CloudConfigurationManager.GetSetting("StorageConnectionString"));
    CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient();
  
    CloudBlobContainer privateContainer = blobClient.GetContainerReference("privatecontainer");
  
    CloudBlobContainer publicContainer = blobClient.GetContainerReference("testpubliccontainer");
  
    /*
     * Moving is not available directly, so we download from priavte blob and upload to public blob.
     * and delete the file from private file from private blob
     */ 
  
    // getting the blob to move.
    // based on my UI user has t type the name of the file he/she wants to move.
    var prblob = privateContainer.ListBlobs(null, false).OfType<CloudBlockBlob>().FirstOrDefault(b => b.Name == TextBox1.Text);
  
    var stream = prblob.OpenRead();
  
    var blobref = publicContainer.GetBlockBlobReference(prblob.Name);
    blobref.UploadFromStream(stream);
  
    stream.Close();
  
    prblob.DeleteIfExists();           
}

Finally the below code samples how to query the files in a blob.

protected void BtnGetVideos_Click(object sender, EventArgs e)
{
    var storageAccount = Microsoft.WindowsAzure.Storage.CloudStorageAccount.Parse(CloudConfigurationManager.GetSetting("StorageConnectionString"));
  
    // creates a blob client
    CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient();
  
   
    CloudBlobContainer publiccontainer = blobClient.GetContainerReference("testpubliccontainer");
    List<BlobDetails> list2 = new List<BlobDetails>();
  
    foreach (IListBlobItem item in publiccontainer.ListBlobs(null, false))
    {
        if (item.GetType() == typeof(CloudBlockBlob))
        {
            CloudBlockBlob blob = (CloudBlockBlob)item;
            list2.Add(new BlobDetails() { BlobName = blob.Name, URL = blob.Uri.AbsoluteUri });
        }
    }
}

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