John McCormack DBA

SQL Server Databases and Cloud

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Delete unused instances to save money in Azure

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My final tip in my series 7 ways for data teams to save money in Azure is to delete unused instances (and orphaned storage) to save money in Azure.

Delete unused instances

red delete key on keyboard

It’s easy to spin up instances in Azure, especially for developers if you haven’t implemented a tight permissions policy. Pet projects and Proof of Concepts (POCs) get created regularly and the person involved needs to remember to delete all resources or else you will be charged indefinitely.

Even services which can be stopped and deallocated such as Virtual Machines will cost you money if they are not deleted. Why? If you don’t delete unused instances in Azure, you still pay for all of the associated costs including the storage which can be significant. Moreover, you need to specifically delete your storage when your delete those VMs or you’ll keep paying for that too. That is known as orphaned storage or unattached storage, and it is not cheap.

A script to find unattached storage

Microsoft published a PowerShell script to find unattached storage in azure which you can run to list out anywhere it occurs in your subscriptions.

Use resource groups for POCs

I would encourage developers and engineers to use a resource group for POCs. This way, when it is done, the whole resource group can be obliterated in one go, leaving nothing behind.

Azure policies and tagging

Once you have got rid of all your old unused instances and orphaned storage, you may want to prevent team members from doing the same thing again. This is where a combination of Azure policies and tagging comes in handy. You can set policies to prevent new services being spun up without the appropriate tags. This Microsoft tutorial explains how to manage tag governance with Azure Policy.

Save with reserved instances – even up to 73%

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This post on how to save money with Azure Reserved instances is part of a 7 part series on cost optimisation with Azure.

thin calendar

Save with reserved instances

Did you say “Save 73% with reserved instances”? I did. In fact, Azure even advertise you can save up to 80% if you combine reserved instances (RI) with Azure Hybrid Benefit (AHB). So what do we mean by reserved instances?

What is a reserved instance?

A reserved instance is a way of reserving capacity in Azure. You are offered a discount by agreeing to a 1 or 3 year commitment. You can choose to pay an element up from to reduce your monthly bill, or you can just pay monthly. Paying monthly does not cost more than paying a portion of the cost upfront so it comes down to a preference for you or your company. Savings are made against compute costs, but not licence costs such as SQL Server Enterprise.

When would I reserve

If you know that you would need an instance for 12 months or longer, it is usually worth taking a reserved instance. A typical scenario for this would be a production SQL Server running in Azure VM or a production SQL Database. If you have a stable workload that you don’t see changing in the near future, reservations are a good bet.

Save with Reserved Instances (Examples)

For this example, you are running SQL Server enterprise on E8s 4s VMs in UK West. You have a cluster of 3 to support your availability groups.

ReservationCompute costWindows licence costSQL licence costTotal monthly cost
Pay as you go£995.66£600.66£4,896.68£6,493.04
1 yr reserved£587.31£600.66£4,896.68£6,084.65
3 yr reserved£378.25£600.66£4,896.68£5,875.59
3 x E8s v4 (8 vCPUs, 64 GB RAM); Windows – SQL Server; 3 year reserved; 0 managed OS disks – S4, 100 transaction units; Inter-region transfer type, 5 GB outbound data transfer from UK West to East Asia

Alternatively, look at the potential savings with Azure SQL DB. In this example, we are looking at a SQL DB, 8 vCore provisioned instance in UK West on General Purpose tier.

ReservationCompute costSQL licence costTotal monthly cost
Pay as you go£828.17£435.11£1,263.29
1 yr reserved£538.11£435.11£973.22
3 yr reserved£372.67£435.11£807.78
1 x Single Database, vCore, RA-GRS backup storage, General Purpose, Provisioned, Gen 5, Local redundancy, 1 8 vCore instance(s) x 730 Hours, 32 GB Storage, 0 GB backup storage

I hesitated to put prices on here because they will change more frequently than I can update the blog but it gives you a general idea. For up to date pricing, please always refer to the Azure Pricing Calculator.

Reserved Instance Allocation

Thankfully, you don’t need to specify which instance uses the allocation, it is just available at an hourly grain level. If you have a live instance that matches your reservation, the reservation credits are used for billing. If you drop an instance and you have another eligible instance type, it will automatically uses the allocation. The allocation is on a use it or lose it basis. If you have a reservation but no suitable resource to use the allocation, you lose it. If you have more instances than reservations, you pay on PAYG terms for anything above your reservation levels.

What type of resources can I reserve

As this post is directed at Azure SQL Data professionals; it is worth pointing out Virtual machines, SQL Database, Azure Synapse Analytics and Azure Blob Storage. It’s also encouraging to see discounts available for MySQL, MariaDB and PostgreSQL.

Azure services eligible to be reserved instances

What if my needs change?

Despite being a long term commitment, Reserved Instances are fairly flexible as Microsoft acknowledges that customers’ needs will change from time to time. You can exchange or cancel reservations as your needs change up to limits imposed by Microsoft.

Save money with Azure SQL DB serverless

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This post on how to save money with Azure SQL DB Serverless is part of a 7 part series on cost optimisation with Azure.

Provisioned vs Serverless

Laptop computer with dollar bills

The default option is provisioned which means you are provisioned with the resources you request, and you keep them for as long as you need them. e.g. If you want 2 vCores and 32GB of storage, you have it permanently, or until you shut down the resource.

Serverless means that although your storage is provisioned, your compute resources are on demand. If you enable automatic pausing of your SQL database, this will happen after a period of time defined by you. Whilst the database is paused, you are not charged for compute costs.

So how do you save money with Azure SQL DB Serverless

Autopause

You can set your database to auto pause if there is no activity. The auto-pause delay period must be between 1 hour and 7 days. When your database is completely paused, you only pay for storage. Auto pause in optional so you can keep the database online all the time, but just benefit from the auto-scaling capabilities. ↙

Autoscaling

You can set a maximum number of vCores up to 40 and a minimum number of vCores of 0.5. The allowed minimum is related to the maximum you set. e.g. Where maximum vCores are set to 4 or fewer, you can set a minimum of 0.5.

Azure SQL DB will scale as required meaning you only pay for what you need. You could allow for some head room by setting a higher max vCore limit than you need, just beware that if it is needed, you will be charged for it.

Per second billing

Bear in mind as well that SQL DB Serverless offers per second billing. You pay for increased resources only when you need them. The billing is quite complex for Azure SQL DB Serverless, and you should read this billing guide for more information.

For up to date pricing information, please always refer directly to the Azure SQL DB pricing page.

Remember retry logic

When your database is paused, the first connection attempt will fail with error code 40613. If your database client has connection retry logic, you won’t need to do anything else. Otherwise, you will need to code this logic into your application.

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7 ways for data teams to save money in Azure

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Save money in Azure

save money in azure - piggy bank with sunglasses

In this series of posts, I list 7 ways to quickly save money in Azure by using cost optimisation principles. Get on top of your cloud costs and start saving money by putting these into action. Whilst this series is specific to Azure, most of the principles can be applied to other public cloud providers. The only thing that differs is the product. Think RDS as an equivalent for SQL DB or S3 for Storage Accounts.

It’s important to keep on top of your cloud costs. Operating in the cloud means it is easy to just spin up new instances in minutes. Whilst that is great and allows company to work in agile manner, the switch to an Operational Expenditure (OPEX) model means that the cost increase can be gradual and go unnoticed.

1. Review your backup retention policy

Azure IaaS SQL Backups – Stop burning money

2. Right size your Azure SQL DBs and managed instances

Your Azure SQL Database and Managed Instance is too big

3. Turn non production instances off out of hours

Turn the cloud off at bedtime to save 70%

4. Right Size your VMs to save money in Azure

Your Azure SQL Virtual Machine might be too big

5. Consider moving to Azure SQL DB serverless

Save money with Azure SQL DB serverless

6. Reserved instances

Save with reserved instances – even up to 73%

7. Delete unused instances

Delete unused instances to save money in Azure

Bonus steps:

This mini series of steps are also important.

  1. Implement Elastic Pools to share resources
  2. Look to see if you are eligible for Azure Hybrid Benefit

Everybody wins

By optimising your costs in Azure and ensuring you are paying the right price for all of your services, everybody wins. Not only are you helping your company save money, it is good for your career and it could even save jobs in your company. Not to mention turning off what you don’t use is good for the environment too.

Need some help? – Book a call

Please get in touch if you would like to schedule a free introductory 15 minute call for some help in reducing your Azure bill.

Your Azure SQL Virtual Machine might be too big

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Cost optimisation

This is post #4 in my series on 7 ways for data teams to save money in Azure. Cost optimisation is crucial to any organisation that operates in the cloud, as costs can and do run away from away you without regular attention.

To avoid repetition of my my post regarding the size of your Azure SQL DBs, please read that to understand the concepts of elasticity, scalability and CAPEX vs OPEX.

One great thing about the cloud is that you can change your mind, or adjust as you go along. Unlike days gone by where you would have a bought a giant SQL Server and ran about 10% utilisation (just to allow room for future growth), you can be much smarter now and only pay for what you need.

Is my instance oversized?

You should be collecting metrics on CPU and memory, as well as looking at your throughput and disk latencies to see how well you are sized. If your CPU is always below 50%, including spikes and you haven’t identified memory pressure, you can look at scaling down. In an ideal world, you should run load tests against the old and new instance types, and compare them before making a decision. Cutting CPUs will give you the biggest financial saving in Azure due to the way that licensing works.

Is my instance undersized?

If your CPU is regularly pinned above 85%, you need to take action. Scaling up is one option, improving your queries is another. Some people will choose to scale up and then plan fix their queries, with the ambition to scale back down again later. In my experience, this rarely happens and they just accept the new instance size as normal. Other work becomes the priority. If you can hold off scaling your instance to give you time to fix your expensive queries first, I would recommend it.

Try not to rush a decision, there are so many instance types and sizes to choose from, each one optimised for a different use case. Do your research and choose the most appropriate instance type, not just next the one up.

I do need more compute power, what’s next?

SQL Server is licensed by the core. The more cores, the higher your licensing costs. However although instance classes tend to double cores and memory as you step up to the next level, there is a smarter way to do it. If you have determined that you don’t need more CPU but you do need more memory, look into the memory optimised instances such as the E-Series.

Looking at the table below, imagine you are on a D16 V4 which provides 64 GB of RAM, but you need to increase your RAM to 128 GB. If you choose the next highest D-Series machine (D32 V4), you double your costs. You might get the extra cores, and they will also help performance, but the expense is unjustified.

Consider instead changing to an E-Series (E16s V4) where you can keep your cores at 16, meaning no change to Windows or SQL licensing costs but you also get the desired 128 GB of RAM. You only pay £158 more per month. *

Instance TypeCPUsMemory (RAM)Monthly cost
D16 V41664 GBCompute £505.45
OS (Windows) £400.44
SQL Licence £3,264.45
Total £4,170.34
D32 V432128 GBCompute £1011.44
OS (Windows) £800.88
SQL Licence £6,528.91
Total £8,341.22
E16s V416128 GBCompute £663.77
OS (Windows) £400.44
SQL Licence £3,264.45
Total £4,328.67
* Prices taken from Azure Calculator on 18/1/2021. Subject to change

Constrained CPU Instances

For memory intensive applications such as SQL Server, constrained CPU instances provide another tool in the battle for cost optimisation.

Say you actually needed 256 GB of RAM but you would still be ok with 16 cores. Sticking with the D-Series, you would need to go up to 64 cores to get the desired memory. You can take the idea of memory optimisation a step further with constrained CPU instances. With these, you get the extra CPUs but they are not available to you. This allows an instance with even more RAM than the memory optimised instances. This means that whilst you have increased compute costs, you don’t have increased license costs as you only pay licenses based on available CPUs. This is a significant saving as you move into higher instance tiers.

Instance TypeCPUsMemory (RAM)Monthly cost
D64s V464256 GBCompute £2,022.33
OS (Windows) £1,601.76
SQL Licence £13,057.81
Total £16,681.90
E32 16s V416 available256 GBCompute £1,327.00
OS (Windows) £800.88
SQL Licence £3,264.45
Total £5,392.33
* Prices taken from Azure Calculator on 18/1/2021. Subject to change

Cost optimisation summary

Don’t provision for what you will need in the future, size your instance for what you need now and keep on top of it. Changing is quick and easy. Be aware of non standard instance types like memory optimised and Constrained CPU to maximise savings against your SQL licensing costs.

Play about with the Azure pricing calculator in order to compare instance types.

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