Unlocking More Power with Flexible Memory in Azure SQL Managed Instance

UrosMilanovic

Microsoft

Jun 18, 2025

Customize the memory-to-vCore ratio in your SQL Managed Instance, now generally available!

Service updates

Sep 28th 2026.

Business Critical: locally redundant and zone-redundant instances. Flexible memory is generally available (GA) for the Business Critical service tier.

Aug 17th 2026.

Next-gen General Purpose: zone-redundant instances. Flexible memory for the Next-gen General purpose tier is in public preview.

May 6th 2026.

Next-gen General Purpose: locally redundant instances. Flexible memory for the Next-gen General purpose tier is generally available (GA)

As data workloads grow in complexity and scale, so does the need for more adaptable and performant database infrastructure. That’s why we’re excited to introduce a new capability in Azure SQL Managed Instance: Flexible Memory, now generally available.

What Is Flexible Memory?

Flexible Memory allows you to customize the memory-to-vCore ratio in your SQL Managed Instance, enabling finer control over both performance and cost based on your workload requirements.

This capability is part of the next-generation General Purpose and Business Critical tiers. It introduces a memory slider, which enables you to scale memory independently within supported limits - without changing the number of vCores.

The memory slider is currently available only on premium-series hardware.

Why It Matters

Traditionally, memory allocation in SQL Managed Instance was fixed per vCore. With Flexible Memory, you can now:

Increase memory beyond the default allocation
Optimize for memory-intensive workloads without overprovisioning compute
Pay only for what you use - additional memory is billed per GB/hour

This flexibility is especially valuable for scenarios like analytics, caching, or workloads with large buffer pool requirements.

How It Works

Memory scales based on the number of vCores and the selected hardware tier:

Hardware Tier	Memory per vCore (GB)
Standard-series	5.1
Premium series	7–12
Premium series (memory-optimized)	Up to 13.6

You can select from predefined memory ratios (e.g., 7, 8, 10, 12 GB per vCore) depending on your configuration. For example, a 10 vCore instance can be configured with 70 GB to 120 GB of memory.

One of the most powerful aspects of the Flexible Memory feature is the ability to select from a range of memory-to-vCore ratios. These “click stops” allow you to tailor memory allocation precisely to your workload’s needs - whether you’re optimizing for performance, cost, or both. The table below outlines the available configurations for Premium Series hardware, showing how memory scales across 16 vCore sizes:

vCores	Available Ratios	Total Memory Options (GB)
4	7, 8, 10, 12	28, 32, 40, 48
6	7, 8, 10, 12	42, 48, 60, 72
8	7, 8, 10, 12	56, 64, 80, 96
10	7, 8, 10, 12	70, 80, 100, 120
12	7, 8, 10, 12	84, 96, 120, 144
16	7, 8, 10, 12	112, 128, 160, 192
20	7, 8, 10, 12	140, 160, 200, 240
24	7, 8, 10, 12	168, 192, 240, 288
32	7, 8, 10, 12	224, 256, 320, 384
40	7, 8, 10, 12	280, 320, 400, 480
48	7, 8, 10	336, 384, 480
56	7, 8	392, 448
64	7	448
80	7	560
96	5.83	560
128	4.38	560

Pricing model

Flexible Memory introduces a usage-based pricing model that ensures you only pay for the memory you actually consume beyond the default allocation. This model is designed to give you the flexibility to scale memory without overcommitting on compute resources - and without paying for unused capacity.

How it works:

Default memory is calculated based on the minimum memory-to-vCore ratio
Billable memory is the difference between your configured memory and the default allocation.
Billing is per GB/hour, so you’re charged only for the additional memory used over time.

Let’s take an example of SQL Managed Instance running on premium series hardware with 4 vCores and 40GB of memory.

Configuration	Value
vCores	4
Configured Memory	40 GB
Default Memory (4 × 7 GB)	28 GB
Billable Memory	12 GB
Billing Unit	Per GB/hour
Charged For	12 GB of additional memory

Management Experience

Changing memory behaves just like changing vCores:

Seamless updates via Azure Portal, PowerShell, SDK or API
Failover group guidance remains the same

Upgrade secondary first
Configurations between primary and secondary should match

Adjusting the memory is fully online operation, with a short failover at the very end of it. The operation will go through the process of allocating the new compute with specified configuration, which takes approximately 60 minutes, with new faster management operations.

API Support

Flexible Memory is fully supported via API (the minimal API version that can be used is 2024-08-01) and Azure Portal. Here’s a sample API snippet to configure memory:

{ "properties": { "memorySizeInGB": 96 } }

Portal support

Summary

The new Flexible Memory capability in Azure SQL Managed Instance empowers you to scale memory independently of compute, offering greater control over performance and cost. With customizable memory-to-vCore ratios, a transparent pricing model, and seamless integration into existing management workflows, this feature is ideal for memory-intensive workloads and dynamic scaling scenarios. Whether you're optimizing for analytics, caching, or simply want more headroom without overprovisioning vCores, Flexible Memory gives you the tools to do it - efficiently and affordably.