Cache for Redis: Scaling from Standard C1 to C2 — HTTP 409 Conflict / Possible Backend Issue

Question

Cache for Redis: Scaling from Standard C1 to C2 — HTTP 409 Conflict / Possible Backend Issue

Valeriu Florin Nitu 0

Problem description

I am attempting to scale my Azure Cache for Redis instance from Standard C1 to C2. However, the operation fails repeatedly with an HTTP 409 Conflict, indicating the resource is busy processing a previous update or under maintenance. Despite this, the cache remains operational, and no resource locks are in place. Also, CLI does not report any update operation taking place. I am seeking guidance on resolving this conflict and successfully scaling the resource.

Environment

Azure Cache for Redis in West Europe, Standard C1 SKU

What I've already tried

I have tried to scale using both Azure Portal and CLI commands, including attempting to scale from Standard C1 to C2. I also verified that no resource locks are present and that the provisioning state is Succeeded. Additionally, I reviewed activity logs and resource state, and I confirmed that the operation path is supported and that the UI indicates supported versions.

Current status

Currently, the cache is operational and serving traffic, but the scale operation remains stuck with repeated HTTP 409 conflicts. I am looking for further troubleshooting steps or guidance to resolve this issue and complete the scale-up process.

SIVASANKAR YEDDULA 250 Reputation points Microsoft External Staff Moderator

2026-09-17T08:47:44.8933333+00:00

Hi @Valeriu Florin Nitu ,

Thank you for reaching out to the Microsoft Q&A.

We will look into the request which you created and will let you know the update.

Thanks & Regards,
sivasankar.
SIVASANKAR YEDDULA 250 Reputation points Microsoft External Staff Moderator

2026-09-22T14:21:12.24+00:00

Hi @Valeriu Florin Nitu ,

I hope the information provided has been helpful. If you have any further questions or need additional assistance, please let us know in the comments, and we will be glad to help. If this answer helps, please consider clicking Accept Answer so that other community members with similar questions can benefit as well.

1 answer

Your answer

SIVASANKAR YEDDULA 250 Reputation points Microsoft External Staff Moderator

2026-09-17T08:47:44.8933333+00:00

Hi @Valeriu Florin Nitu ,

Thank you for reaching out to the Microsoft Q&A.

We will look into the request which you created and will let you know the update.

Thanks & Regards,
sivasankar.
SIVASANKAR YEDDULA 250 Reputation points Microsoft External Staff Moderator

2026-09-22T14:21:12.24+00:00

Hi @Valeriu Florin Nitu ,

I hope the information provided has been helpful. If you have any further questions or need additional assistance, please let us know in the comments, and we will be glad to help. If this answer helps, please consider clicking Accept Answer so that other community members with similar questions can benefit as well.

Answer 1

SIVASANKAR YEDDULA 250 Microsoft External Staff Moderator

Hi @Valeriu Florin Nitu ,

First and foremost, I would like to sincerely apologize for the extended duration of this issue and for the frustration caused throughout the investigation. I completely understand your concerns, especially considering that a scaling operation would normally be expected to complete within a much shorter timeframe.

I appreciate your patience and your efforts in continuing to work through the issue. I am glad to hear that you were ultimately able to successfully scale the Azure Cache for Redis instance to the desired tier.

As you have confirmed that the scaling operation has completed successfully and no further assistance is currently required, we will proceed with closing this support case.

On behalf of Microsoft, I would like to thank you for your cooperation and again apologize for the experience. Should you require any further assistance in the future, please do not hesitate to reach out to us. We will be happy to help.

Thank you for working with Microsoft Support.

SIVASANKAR YEDDULA 250 Reputation points Microsoft External Staff Moderator

2026-09-19T07:47:37.24+00:00
Hi @Valeriu Florin Nitu ,

Thank you for sharing the details.

Based on the reported HTTP 409 message, Azure Cache for Redis considers a management operation, such as scaling or patching, to be in progress, or the cache may be undergoing system maintenance. While such an operation is in progress, other management operations are blocked. The cache can remain fully functional for client operations during this condition.

As mitigation, please follow the below steps:

Avoid submitting repeated scale requests while the HTTP 409 condition is present.

Review Diagnose and solve problems and Resource health for the cache in the Azure portal.

Allow the existing management operation or maintenance activity to clear, and then retry the Standard C1 to C2 scale operation.

Please also review the cache load and memory utilization before retrying the scale operation.

If the same "cache is busy" error continues for more than 12 hours, please engage Azure Support for further investigation.

Scaling up is supported for the Standard tier, so moving from Standard C1 to a larger Standard cache size is a supported scaling scenario.

At this stage, we should not confirm this as a backend issue because the available information does not establish the underlying root cause. If the condition persists beyond the documented period, backend investigation may be required to validate the resource's management state.