Hi Ling,

This CEP is well written. Can you please add the references you listed to below 
to the CEP as well? I hope these will be helpful for readers.

Thanks,
Shailaja



> On Mar 13, 2026, at 9:50 AM, Ling Mao <[email protected]> wrote:
> 
> 1.Cluster-Wide Quota
> Although I have listed it as "Future Work," we all know that "Future Work" 
> sometimes means "I may never do it :)” Implementing that in a leaderless 
> architecture is challenging, particularly because we lack a centralized 
> component(like the Request Router/global admission control in DynamoDB [6]), 
> that provides a global, accurate, and real-time view of the system's 
> load/traffic information.
> 
> 2.Rejected Alternatives
> Quota is a well-established feature that has been implemented in many other 
> distributed systems for years, including Apache Kafka[1], HBase[2], 
> Pulsar[3], Hadoop[4], and ZooKeeper[5]. This CEP aims to learn from these 
> systems and adopt their best practices.
> 
> References:
> [1] https://docs.confluent.io/kafka/design/quotas.html
> [2] https://product.hubspot.com/blog/hbase-share-resources
> [3] 
> https://pulsar-neighborhood.io/articles/apache-pulsar-multi-tenancy-explained/
> [4] 
> https://hadoop.apache.org/docs/stable/hadoop-project-dist/hadoop-hdfs/HdfsQuotaAdminGuide.html
> [5] https://zookeeper.apache.org/doc/r3.9.4/zookeeperQuotas.html
> [6] https://blog.bytebytego.com/p/a-deep-dive-into-amazon-dynamodb
> 
> On 2026/03/04 18:14:56 Bernardo Botella wrote:
>> Thanks for pointing this out Stefan!
>> 
>> I agree that these proposals are closely related, but I view them as 
>> complementary rather than competing.
>> 
>> I believe they protect the cluster at two different levels: CEP-61 provides 
>> a flexible layer for multi tenancy where operators can set specific policies 
>> to meet different customer requirements. This would even allow for 
>> 'over-provisioning' quotas while maintaining a safety net that CEP-41 could 
>> provide, protecting nodes from total meltdown if those limits are reached or 
>> if system signals show distress.
>> 
>> That being said, I think there is value on exploring those two proposals in 
>> parallel. 
>> 
>> On the actual CEP-61, a couple of thoughts:
>> - I think there would be value on trying to articulate how the cluster wide 
>> quota management will work in the future. I see gossip as one proposed path 
>> forward. I'd love to hear the thoughts of those who know more than I do 
>> around the protocol and the potential alternatives. I am basically trying to 
>> gain the confidence that we actually have a path forward for cluster wide 
>> quota handling, even if it is implemented in a different step of this CEP 
>> delivery.
>> - Acording to the CEP template, I'd love to see a rejected alternatives 
>> section on the CEP.
>> 
>> Really curious on what others think!
>> Bernardo
>> 
>> 
>> 
>>> On Mar 4, 2026, at 10:31 AM, Štefan Miklošovič <[email protected]> 
>>> wrote:
>>> 
>>> Hey,
>>> 
>>> just saying there is also (1) already. There seems to be competing
>>> proposals in this space we should form some opinions on and proceed
>>> with the better one or pick the best approaches from both.
>>> 
>>> (1) 
>>> https://cwiki.apache.org/confluence/display/CASSANDRA/CEP-41+%28DRAFT%29+Apache+Cassandra+Unified+Rate+Limiter
>>> 
>>> On Wed, Mar 4, 2026 at 9:47 AM Ling Mao <[email protected]> wrote:
>>>> 
>>>> I have published CEP-61: Quota Management. You can find the full proposal 
>>>> here: 
>>>> [https://cwiki.apache.org/confluence/display/CASSANDRA/CEP-61%3A+Quota+Management].
>>>>  I would appreciate any feedback or review comments from the community.
>>>> 
>>>> On 2026/02/24 09:47:44 Justin Ling Mao wrote:
>>>>> Hi everyone:
>>>>> I have created a JIRA ticket:CASSANDRA-21158, regarding a new feature: 
>>>>> Implementing quota management for multi-tenant.You can find the design 
>>>>> document here: 
>>>>> https://docs.google.com/document/d/1BGDjBsuVkuISbN8lqxoZUuGbx0qRhuNA8BAxF48a24kIf
>>>>>  you are interested, please join the discussion. Once we’ve had a 
>>>>> thorough discussion and if the community finds this feature valuable, I 
>>>>> will proceed to create a CEP (Cassandra Enhancement Proposal) and 
>>>>> subsequently submit a PR.
>>>>> Looking forward to your feedback!
>>>>> 
>>>>> --------------------------------
>>>>> 
>>>>> Best regards
>>>>> Justin Ling Mao
>>>>> Beijing,China
>>>>> 
>> 
>> 

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