How many Oracle instances can be consolidated on a single server?

According to Exadata consolidation guide, this is what you can consolidate on Oracle specialized Hardware:

NOTE: The maximum number of database instances per cluster is 512 for Oracle 11g Release 1 and higher. An upper limit of 128 database instances per X2-2 or X3-2 database node and 256 database instances per X2-8 or X3-8 database node is recommended. The actual number of database instances per database node or cluster depends on application workload and their corresponding system resource consumption.


But how many instances are actually beeing consolidated by DBAs from all around the world?

I’ve asked it to the Twitter community

I’ve sent this tweet a couple of weeks ago and I would like to consolidate some replies into a single blog post.


My customer environment however, was NOT a production one. On the production they have 45.

Some replies…




Wissem cores 73 on a production system, 1TB memory!


Chris correctly suggests to give a try to the new 12c consolidation features:


Kevin, as a great expert, already experimented one hundred instances environment:

But Bertrand impresses with his numbers!






Intel platform with 1TB of RAM = Xeon E7, suggests Kevin:




Flashdba has seen 87 instances on a single host, but on a Multi-node RAC: but still huge and complex!





Does this thread of tweets reply to the question? Are you planning to consolidate your Oracle environment? If you have questions about how to plan your consolidation, don’t hesitate to get in touch! πŸ™‚


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Principal Product Manager at Oracle
Ludovico is a member of the Oracle Database High Availability (HA), Scalability & Maximum Availability Architecture (MAA) Product Management team in Oracle. He focuses on Oracle Data Guard, Flashback technologies, and Cloud MAA.

5 thoughts on “How many Oracle instances can be consolidated on a single server?

  1. Yep, it’s not a single node RAC, rather a multi-node RAC where every database has only one instance started. The failover is automatic and the migration from one node to another is transparent to the applications. IMHO It’s ideal for small databases.
    More info here:

    GI is the Grid infrastructure (the foundation for a RAC or RAC One architecture) and ASM is the “storage manager” from Oracle that replaces cluster filesystems delivering better performance and manageability.

    Hope it helps

  2. Thnaks for replying. My unerstanding was RAC is mostly used for high availability for critical applications. Our applications are mostly vendor based. With single node RAC, how we do achieve failover? β€œo-motion” and GI+ASM are new to me. I will check doumentation and let you know if I have any questions.

  3. Hi Ramki,
    for sure! not only, I think it could be a FAR BETTER solution compared to VM/Linux, because you don’t have to take care of many and many operating systems but rather you can concentrate on your databases and make huge savings on storage and memory.
    If you have to start from scratch with a new architecture, for many small databases I would suggest a RAC One Node cluster, so you can benefit from “o-motion” and leverage GI+ASM whilst reducing licensing costs of a full RAC solution.

    If you’re on Oracle Standard, however, you can do a full RAC SE with one or more clusters composed by a maximum of two nodes each (4 socket total for each cluster). Different costs AND different limitations! πŸ™‚



  4. We are looking forward to consolidate 100+ small Oracle databases. Do you think RAC is still a viable option for consolidation compared VM/Linux?

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