Hi malvarez5,
Here is the Siteminder 12.52 platform support matrix for your reference - SAP Portal Services
Question 1: Can any version of Oracle be used without upgrading Siteminder?
Answer 1: You can use supported version of Oracle DB as Policystore and userstore without upgrading policy server. As per platform support matrix Oracle 12c is supported from 12.52 SP1 onwards ? so what is your exact version of Policyserver ?- 12.52 SP ? CR ?
Question 2: Does Oracle need to run on RedHat linux or can it run on any linux flavor? I no longer have the option to use RedHat.
Answer 2: It does not matter where you run your DB as long as your are using supported version of DB version.
Question 3: Should Oracle compatabily flag be set to 11G to ensure no issues?
Answer 3: Not really required, as Oracle 12c is officially supported from SP1 on wards. If your policy server is just base version of 12.52 then 12c is not supported. You may need to open a support case to check about "compatibility flag".
Question 4: is there some guide for migrating Oracle versions? We cannot upgrade in place. We have to install oracle on a new linux instance and then restore our users and policies to that instance from the old instance.
Answer 4: Step-1 : Here are the instructions to configure an Oracle DB as Policy store - Configure an Oracle Policy Store - CA Single Sign-On - 12.52 SP1 - CA Technologies Documentation
Step-2 : Policy store migration can be done at DB level by DBA's or using Policy Server utilities such as XPSExport for Policy Backup - CA Knowledge.
Note - Userstore migration has to done at DB level only.
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And finally, End of Life for Siteminder 12.52 version is - February 28, 2019, you may need to consider upgrading your environment to the latest version of SSO 12.8. Refer the below KB article.
https://support.ca.com/us/product-content/status/support-life-cycle/indexes/ca-single-sign-on-release-and-support-lifecycle-dates.html
Regards
Ashok