Exadata Cloud@Customer (ExaC@C) from Oracle is an hybrid solution for customer willing a Cloud-like platform without actually being in the public Cloud. Behind cloud’s concept is a high-level management of complex stuff, like provisioning homes and databases, patching, aso. And this has made classic deployments rather obsolete. ExaC@C brings these Cloud features to a kind of on-prem solution.
What is Exadata?
Exadata is the server behind ExaC@C. Actually, this is not a single server, it’s a set of servers and network equipment inside a full rack. There is two kinds of servers inside an Exadata, compute nodes (at least 2) for running databases, and storage cells (at least 3), for running ASM storage. The main difference compared to any other solution is that storage is aware of database queries and can offload part of the job from the compute nodes to the cells.
Exadata is considered to be the highest-end solution for very demanding and highly critical Oracle databases. As you may guess, this is not for you if you only run a couple of instances.
What is Exadata Could@Customer?
Key points of the ExaC@C:
- A “classic” Exadata installed by Oracle in your data center
- Paid as a cloud subscription (monthly fee) for a number of years
- Included license: Oracle Enterprise Edition Extreme performance (understand with all options)
- Manageable with the OCI console (Oracle’s public cloud portal)
- Manageable with the OCI REST APIs
- Fully integrated to your network as if it were yours
- Run databases inside Virtual Machines clusters
- Configured to your needs with very few limits (root access to VMs)
- Nothing resides in a public Cloud
Promises of ExaC@C
This solution is the Oracle masterpiece regarding databases. The promises are:
- First class performance
- Easy setup
- Easy patching
- Easy provisioning
- Easy Data Guard setup
- Easy backup
- Pay-as-you-run cost
That sounds great. Exadata made easy, this is what some of us always expected! For sure this solution comes at a price point that may not fit your purse. But if you work with hundreds of databases and if Oracle database is one of the most important component in your IT infrastructure, it’s definitely a solution to consider.
Reality: what is really easy?
Once Exadata is in your data center, and linked to OCI with the correct privileges, the first step is to provision the VM clusters. Exadata is a powerful machine, and you will split it into multiple VM clusters for production, test, certification, … Note that most of the time, you will need at least 2 Exadatas, Disaster Recovery not being addressed by using another VM cluster on the same hardware.
Provisioning VM clusters is quite easy and is not really a DBA task, as it consists of providing CPU sizing, memory, disk space and network configuration. The virtual servers will then be provisioned, and for the RAC setup, because Exadata means RAC, each component is configured automatically during VM cluster provisioning. You can compare this to provisioning an HA Oracle Database Appliance on which you don’t do the RAC setup yourself.
Provisioning DB homes and databases is also very easy once VM clusters are available, straight from the OCI console. You eventually don’t need any DBA knowledge for that, just choose your version, database name and character set and it’s done.
Provisioning PDBs is also included in OCI, this is quite a new feature.
Data Guard configuration is also so easy. Create a Data Guard configuration is choosing target VM cluster for creating the standby and protection mode for your configuration, and everything is done automatically. You can later switchover or failover from OCI. Goodbye broker and command line interface.
Regarding backup, each database can be configured for automatic backup: just provide your usual nfs share and your target backup retention and it will be configured and scheduled automatically. Restore is also done from the OCI console, this is really nice.
Regarding these points, obviously there is less work for you. Or more precisely, these tasks will take you less time to complete.
Reality: limits of the easy stuff
Everything would be easy if Oracle and Exadata together were less complex. Underlying complexity on these technologies is still there.
In case of a problem, because problems can happen on this platform too, troubleshooting will be needed. And you will need the knowledge on RAC, Data Guard, Linux, and so on.
Another point is that some easy-to-implement stuff may not fit your needs.
For example, if a specific configuration is needed for Data Guard (basically if some databases need 2 standbys), you will need to configure it yourself, with a classic tools like dgmgrl.
This is the same for backups, if you need to build a complex backup strategy based on a mix of disk backups and tape backups, automatic backup will not allow you to do that, at least not yet. You will then go back to rman and shell scripting, and you will need a scheduler.
Fortunately, your ExaC@C will benefit from new features quite regularly. I’ve only been working 1 year with this platform and I already seen some great improvements. Improvements are mainly new features brought to the OCI console: you can still manage everything manually if you want to.
DBA tasks on ExaC@C
There is still a lot of work for a DBA on this platform:
- Provisioning DB homes, databases and PDBs
- Defining resources between PDB, CDB and VM clusters
- Tuning the databases
- Planning and applying patches, because you will decide when you apply them once they are available
- Monitoring the platform, databases, backups
- Doing the migrations from you current environment
- Leveraging the potential of the platform (using available options, optimizing offload to the cells)
- Managing credits and resources according to planned needs
Managing credits is a hot topic when it comes to resources on the Cloud. Basically every active resource will cost something. On ExaC@C, you should know that you can provision a VM cluster with zero cores, and increase the number of cores when you start to use it. You may also think about stopping some of your VM clusters when they are not absolutely needed. For example during the night. This is also something greener than letting everything running 24h a day.
Don’t be afraid of this solution. ExaC@C will not steal your job, it will change it a little bit. There is still a lot to do for DBAs, the few things removed from your to do list will be replaced by other tasks, more interesting ones in my opinion. This is the real challenge. A DBA should continue learning to keep his job. But this is the same for a lot of other jobs now.