Does cosmos db auto increase throughput when throttle

Question

Does cosmos db auto increase throughput when throttle

Jason Le 96

The database was initially provisioned at 400k ru/s autoscale. I see provisioned throughput automatically increased from time to time. Right now, the data size has increased to 6.5TB, max throughput is now 3094k ru/s. It's much higher than minimum throughput requirement for storage. I do see light throttle occasionally. I wander if this is the reason database keep scaling out. Thanks

Answer 1

Anurag Sharma 17,261

Hi @Jason Le , welcome to Microsoft Q&A forum.

Yes Azure Cosmos DB automatically increases the throughput of database/container if storage size exceeds a limit. As per the article, "If the storage limit associated with the max throughput of the database or container is exceeded, Azure Cosmos DB will automatically increase the max throughput to the next highest RU/s that can support that level of storage.
For example, if you start with a max RU/s of 50,000 RU/s (scales between 5000 - 50,000 RU/s), you can store up to 500 GB of data. If you exceed 500 GB - e.g. storage is now 600 GB, the new maximum RU/s will be 60,000 RU/s (scales between 6000 - 60,000 RU/s)."

Please let me know if this information helps or else we can discuss further.

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If answer helps, please mark it 'Accept Answer'

Jason Le 96 Reputation points

2021-04-22T10:01:43.597+00:00

But the number does not add up. 6.5TB should require 650k RU/s. What I am seeing is 3094k RU/s. How do you explain that?
Anurag Sharma 17,261 Reputation points

2021-04-22T11:19:36.817+00:00
Thanks for the reply. Could you please tell me how many containers do you have in the database? You can try based on below formula as well:

MAX(4000, highest max RU/s ever provisioned / 10, current storage in GB * 100, 4000 + (MAX(Container count - 25, 0) * 1000)), rounded to nearest 1000 RU/s.

Limits for autoscale provisioned throughput

If this does not give the right calculation, we might need to raise a ticket with the support team. Please let me know.
Jason Le 96 Reputation points

2021-04-22T11:42:37.33+00:00

The database has 2 containers. It still won't add up.
Anurag Sharma 17,261 Reputation points

2021-04-23T05:56:02.07+00:00

This looks like an issue in this case. Could you please once confirm if you checked the size for the database as mentioned in below screenshot:

]1

I will escalate this issue to product team based on your response.
Jason Le 96 Reputation points

2021-04-23T18:50:06.743+00:00

I see the database scale out even more. It has now 3264000 RU/s (327 physical partition).
Anurag Sharma 17,261 Reputation points

2021-04-26T06:56:11.94+00:00

Thanks for the details provided. I have escalated this to internal product group and will respond at the earliest based on their reply.
Jason Le 96 Reputation points

2021-05-11T15:46:00.127+00:00

Hi, Anurag. Is there any update on this issue?

Does cosmos db auto increase throughput when throttle

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