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Category: Cloud

Sampling Data Lake Data

Alex Whittles shows how to use U-SQL to sample data to read in Power BI:

The answer is sampling, we don’t bring in 100% of the data, but maybe 10%, or 1%, or even 0.01%, it depends how much you need to reduce your dataset. It is however critical to know how to sample data correctly in order to maintain a level of accuracy of data in your reports.

Option 1: Take the top x rows of data
Don’t do it. Ever. Just no.
What if the source data you’ve been given is pre-sorted by product or region, you’d end up with only data from products starting with ‘a’, which would give you some wildly unpredictable results.

Option 2: Take a random % sample
Now we’re talking. This option will take, for example 1 in every 100 rows of data, so it’s picking up an even distribution of data throughout the dataset. This seems a much better option, so how do we do it?

Read on for a couple of sampling methods.

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Backing Up To Azure Storage

Neil Gelder shows how to back up directly to Azure blob storage:

The URL is the one from the container we made a note of and the credential is the one we created in the last step.

Now if we return to the container screen in the Azure Console and refresh the screen you’ll see your backup file like below

My personal preference here would be to back up locally and then have a job migrate backups to Azure or S3.  That storage is 1-3 cents per GB per month (and even cheaper if you’re willing to store the data in Glacier), so for more small to mid-sized organizations running databases in the tens of gigs, it’s a great way of getting around only being able to store a week or two worth of backups on-site.

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Beginning With Amazon Athena

Jen Underwood looks at the basics behind Amazon Athena:

Today early adopters of Amazon Athena are using it for big data analytics pipeline projects along with Kinesis streaming data and other Amazon data sources.

Athena is serverless parallel query pay-per-use service. There is no infrastructure to set up or manage. It scales automatically and can handle large datasets or complex distributed queries.

The easy way of thinking about Athena is that it’s ElasticMapReduce (a pay-as-you-go Hadoop cluster) without the ceremony of administering or spinning up the cluster.

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Automating Stats Maintenance With Azure SQL DW

Grant Fritchey shows how to create automated statistics maintenance for an Azure SQL Data Warehouse database:

NOTE: The most important habit you can start with in Azure is putting everything into discrete, planned, Resource Groups. These make management so much easier.

Once the account is set, the first thing you need is to create a Runbook. There is a collection of them for your use within Azure. None of them are immediately applicable for what I need. I’m just writing a really simple Powershell script to do what I want:

Runbooks are an important part of Azure maintenance, and this is a gentle introduction to them.

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Right-Sizing Elastic Pools

Arun Sirpal points out a nice potential money-saving feature with Azure:

The recommendation is to setup a standard 50 EDTU pool. I am convinced that this pool is a new pricing tier. Even though the cost saving is small it is still clever that it suggests this. I assume the analysis done in the background really does understand my utilization patterns as we know that the patterns are absolutely crucial for when using elastic pools so it is something to definitely consider.

Within a click of a button the portal will create it for you.

It’s interesting that the feature can actually save you money rather than just telling you that you need to buy more expensive services.

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Secure Enterprise Data Hub On Azure

James Morantus has a two-parter on Azure, Active Directory, and Cloudera’s enterprise data hub solution.  Part one hits on DNS and Samba:

As you can see, the hostname -f command displays a very long FQDN for my VM and hostname -i gives us the IP address associated with the VM. Next, I did a forward DNS lookup using the host FQDN command, which resolved to the IP address. Then, I did a reverse DNS lookup using host IPaddress as shown in the red box above, it did not locate a reverse entry for that IP address. A reverse lookup is a requirement for a CDH deployment. We’ll revisit this later.

Part two looks at tying everything together in the Azure portal as well as within AD:

The remaining steps must be executed as the Cloudera Director admin user you created earlier. In my case, that’s the “azuredirectoradmin” account. All resources created by Cloudera Director in the Azure Portal will be owned by this account. The “root” user is not allowed to create resources on the Azure Portal.

First, we’ll need to create a SSH key as the “azuredirectoradmin” user on the VM where Cloudera Director is installed. This key will be added to our deployment configuration file, which will be added on all the VMs provisioned by Cloudera Director. This will allow us to use passwordless SSH to the cluster nodes with this key.

This isn’t trivial, but considering all that’s going on, it’s rather straightforward.

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R Tools For Visual Studio

Matt Willis has a two-parter on R Tools for Visual Studio.  First, an introduction:

Once all the prerequisites have been installed it is time to move onto the fun stuff! Open up Visual Studio 2015 and add an R Project: File > Add > New Project and select R. You will be presented with the screen below, name the project AutomobileRegression and select OK.

Microsoft have done a fantastic job realising that the settings and toolbar required in R is very different to those required when using Visual Studio, so they have split them out and made it very easy to switch between the two. To switch to the settings designed for using R go to R Tools > Data Science Settings you’ll be presented with two pop ups select Yes on both to proceed. This will now allow you to use all those nifty shortcuts you have learnt to use in RStudio. Anytime you want to go back to the original settings you can do so by going to Tools > Import/Export Settings.

Next is executing an Azure Machine Learning web service within RTVS:

Whilst in R you can implement very complex Machine Learning algorithms, for anyone new to Machine Learning I personally believe Azure Machine Learning is a more suitable tool for being introduced to the concepts.

Please refer to this blog where I have described how to create the Azure Machine Learning web service I will be using in the next section of this blog. You can either use your own web service or follow my other blog, which has been especially written to allow you to follow along with this blog.

Coming back to RTVS we want to execute the web service we have created.

RTVS has grown on me.  It’s still not R Studio and may never be, but they’ve come a long way in a few months.

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Basics Of Azure Analysis Services Management

Bill Anton walks through some of the basics of managing an Azure Analysis Services cube:

The quickest win – from an ROI perspective – for Azure AS is the ability to pause the instance during extended periods of inactivity – for example, at night, when there aren’t any users running reports.

This can be achieved via the Suspend-AzureRmAnalysisServicesServer cmdlet we saw in the previous post.

Read on for a few tips of this ilk, including resizing the server.

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