Where does the database link SYS_HUB come from?

This blog lives a lot from customer’s feedback and updates. And these days, Nicolas Jardot from dbi-services in Switzerland sent me an email asking: Where does the database link SYS_HUB come from? And if he can delete it or if it has any deeper purpose. Neither Google nor MOS reveal a lot of useful information Where does the database link SYS_HUB come from? I took my vanilla 18.3.0 database in our hands-on lab and check: column owner format a5 column db_link format a12 column username format a12 column host format a12 select con_id, owner, db_link, username, host from cdb_db_links; CON_ID…

DBCA 12.2 does not update /etc/oratab in GI / RAC

Interesting things happen. And I learned (credits to Arun Gupta and others) that there is a change in Oracle Database 12.2 environments I wasn’t aware: The DBCA 12.2 does not update /etc/oratab in GI / RAC environments. Let me give you some extra information and hints on this topic as it may cause some strange situations. DBCA 12.2 does not update /etc/oratab in GI / RAC Arun Gupta commented on the blog: Another case in point. DBCA fails to update the /etc/oratab file in 12.2 when a database is created. There is no documentation of this behavior. So, I opened…

GIMR DB in Oracle Database 12.2

I did blog in the past already about the Grid Infrastructure Management Repository Database (GIMR DB): Grid Infrastructure Management Repository (GIMR)database now mandatory in Oracle GI 12.1.0.2 SID and DBNAME are kept the same in Oracle Database 12.2. But there are a few changes and additions in Oracle Database 12.2.0.1. GIMR DB in its own Disk Group During a fresh installation of Oracle Grid Infrastructure 12.2.0.1 you’ll have the chance to create a disk group for GIMR DB: But you can migrate GIMR DB into a separate disk group as well – just make sure the size is large enough…

Keep your patch versions between Grid Infrastructure and Databases Homes in synch

I’ve had some interesting discussions with Anil Nair, our RAC Product Manager and a customer in the past days. The customer was looking for a definite statement that they can have a higher version of Patch Set Updates (PSUs) or Proactive Bundle Patches (BPs) in the Database homes than in the Grid Infrastructure home managing the resources. Can you have different PSU/BP versions between Database and GI homes? Yes, you can have a higher version PSU or BP in the Database home than in the Grid Infrastructure home managing the resources. This is implicitly documented in MOS Note 337737.1 – Oracle…

Grid Infrastructure Management Repository (GIMR) – Datapatch?

I have blogged about the Grid Infrastructure Management Repository (GIMR) a while back: Grid Infrastructure Management Repository (GIMR)database now mandatory in Oracle GI 12.1.0.2 And Markus Michalewicz, our Director of Product Management, Oracle Real Application Clusters (RAC), has published a very interesting and helpful insight article about GIMR on July 30, 2015. Read it here: https://www.linkedin.com/pulse/how-handle-oracle-gimr-markus-michalewicz Since Oracle Database 12.1.0.2 the GIMR database will be created by default – and it is a single tenant database having a CDB$ROOT and one active PDB. Recently the question came up if – in the likely event of applying a PSU or BP…

Upgrade the Operating System in a RAC Environment

Last week at the upgrade workshop in Budapest a customer had a interesting and – I believe – not uncommon question. “How can I upgrade my Linux Operating System in my RAC environment without taking the entire cluster down?” In this specific case the customer wanted to upgrade from RHEL 5.10 to RHEL6 or RHEL7. Let’s assume it’s the typical 2-node-RAC where one wants to upgrade in a rolling fashion. And the data is stored within ASM. Drain Node 1 (i.e. take the workload off) – this will be the node getting upgraded first Remove Node 1 from the  cluster…

Grid Infrastructure PSU Jan 2015 – Am I too intolerant?

Germans are not only known for being precise and timely – but sometimes also for being too direct. Well, Roy could tell you stories … and I always honor his politeness 🙂 Enough about stereotypes. I work with a customer at the moment on their 12c upgrades. And I did recommend the most recent PSU (Patch Set Updates) for their Grid Infrastructure environments running Oracle Restart. Same of course for the database homes but this blog post will just name some findings I’ve had the other night when trying to apply the January 2015 GI PSU to my Oracle Restart…

Grid Infrastructure Management Repository (GIMR) database now mandatory in Oracle GI 12.1.0.2

During the installation of Oracle Grid Infrastructure 12.1.0.1 you’ve had the an option to choose YES/NO to install the Grid Infrastructure Management Repository (GIMR) database MGMTDB – but as of Oracle 12.1.0.2 Grid Infrastructure Management Repository (GIMR) database now mandatory in Oracle GI 12.1.0.2: GIMR database now mandatory in Oracle GI 12.1.0.2 With Oracle Grid Infrastructure 12.1.0.2 this choice has become obsolete and the above screen does not appear anymore. The GIMR database has become mandatory. What do we stored in the GIMR? You’ll find it in the Oracle 12.1.0.2 documentation via this link. In addition please see the changes in Oracle…

Upgrade to Grid Infrastructure – but OCR and VOTING on RAW?

Just received this question from a colleague these days: “The current customer environment is 10.2.0.5 on Linux with a 2 node RAC cluster having OCR and Voting Disks on RAW devices. Customer is concerned about the possibility of upgrading to 11gR2 Grid infrastructure first before they could upgrade to 12c Grid infrastructure.” Now the answer is written down in MOS Note 1572925.1: How to Upgrade to 12c Grid Infrastructure if OCR or Voting File is on Raw/Block Devices Basically the MOS Note says: You will have to relocate your OCR/Voting to a supported device BEFORE you can upgrade to Oracle…

Creating ASM for test purposes in the file system

First of all, I’m back after pausing for a while – sorry for not updating the blog in the past weeks … and you won’t see many updates in the following weeks as it’ll be holiday season (and we Germans have sooooo many public holidays) 🙂 Anyway, back to tech topics. Today I want to test Oracle Restart upgrades. Oracle Restart internally is called SIHA (Single Instance High Availability) which explains the topic a bit more. Basically it means having your database reside in ASM and let Oracle Clusterware take care on it, even though you don’t have a cluster….