Exadata X8M introduces BIG Architectural Changes

Launched at the 2019 Oracle Open Word Conference the Exadata X8M introduces few big architectural changes which make the leading Oracle Database Machine even more attractive.

Among the most relevant changes there are:

  • InfiniBand Network replacement with an Ethernet network fabric
  • Intel Optane DC Persistent Memory inside the Storage Cell
  • New Remote Direct Memory Access (RDMA) functionalities
  • Replacement of the XEN Hypervisor with KVM

InfiniBand Network replacement with an Ethernet network fabric

The characteristic 40Gbit/second InfiniBand network used for all private network communications among database nodes and storage cells has been replaced by a new 100Gbit/second RDMA over Converged Ethernet Fabric (RoCE) based on the Cisco Switch 9336c RoCE .

The new network not only increase 2.5x the throughput but also reduces the communication latancy.

The schema below highlight the network architecture change for all private communications

Intel Optane DC Persistent Memory inside the Storage Cell

Oracle has introduced 1.5TB of Intel Optane DC Persistent Memory as additional storage device inside all Exadata X8M Storage Cell, (no matter if equipped with HC and EF devices), and it is used as accelerator in front of the Flash Memory Cards. In term of speed this new type of ultra fast storage device is located between the DRAM and the Flash Memory, bringing to three the number of multi-tiered storage devices present inside the Storage Cell.

The Exadata unique software is than capable to extract the maximum performance from this HW configuration, automatically detecting and placing the hottest data on the Persistent Memory, reducing the I/O latency of the most critical tasks.

Below is described the list of Storage Cell’s devices ordered by speed.

New Remote Direct Memory Access (RDMA) functionalities

Until now the RDMA was used among database nodes for exchanging Exafusion messages or for Smart Fusion Block Transfer. Starting with Exadata X8M, the RDMA technology is also used to perform direct I/O access to the Persistent Memory of the Storage Cells, bypassing the network and I/O stack and eliminating expensive CPU interrupts and context switches. This optimization reduces the latency by 10x, from 200μs to less than 19μs.

The picture below highlight the “Database Node to Database Node” and the new “Database Node to Storage Cell” communication using RDMA functionalities.

Replacement of the XEN Hypervisor with KVM

Oracle virtualization technology is called Oracle Virtual Machine (OVM) and in a productive invironment it can be implemented with one of this two different products:

  • Xen
  • KVM

Starting with Exadata X8M-2 the virtualization technology in use is KVM instead of Xen. Oracle started replacing Xen with KVM few years ago, for example on the smaller engineered system ODA X7-2M & X7-2S, but for the Exadata took longer, and I think the root cause was the InfiniBand network. Infact KVM is not fully integrated with InfiniBand, and it does not support bridging.

My OOW18 Summary


For those who are interested here my major takeaways from the OOW18


As we all know, since few years the HOTTEST topic advertized at the OOW is “Cloud Computing”, but this time Oracle Cloud was no longer alone!

In fact the focus was divided between the new Oracle OCI Cloud, also named by Larry as Second Generation of Cloud and the Autonomous Database.


OCI Second Gen of Cloud

Here a summary of the major advantages compared to the previous version:

– Security, guaranteed by robots which scan the network for any malicious attack.  

– The cutting edge virtual network, which brings up to 50GB speed and extreme flexibility.

– Bare Metal Infrastructure based on Exadata Machines.

– Aggressive pricing, compared to the competitors.


Autonomous Database.

The Autonomous Database option is now available for OLTP and DWH databases and includes new capabilities like automatic index creation and column stored table conversion. In version 19 it will manage online memory increase and additional tuning options.

As announces during Larry’s keynote, the  Autonomous database will be also available with the Cloud @ Customer option (on Exadata only), ant it will no longer require human labor (DBA and Sys Admin intervention), because Self Provisioning, Self Driving, Self Tuning and Self Repairing.

For non-technical people it looks magic, but it is few steps from what we already use in a standard Oracle 12c Database. In fact Autonomous Database leverages a bunch of database advisors and tuning options, now orchestrated by an Artificial Intelligence and Machine Learning software, in order to provide data-driven predictions and decisions.

Over the next few years, Autonomous Database will be enriched with several new options, improving the quality of live of many DBAs, which will be relieved of the majority of the tedious and recurring tasks, leaving the most added value tasks under their own responsibility.

Last but not least, the Autonomous Database runs in a very high end configurations (Oracle guarantees 99,995% of availability), which is quite expensive to acquire due to the list of mandatory requirements: Exadata, RAC, Active DG, Multitenant, Tuning Pack, Diagnostic Pack etc..


Exadata Machine

Several interesting features are coming next year with the introduction of the INTEL Optane DC Persistent Memory for even faster OLTP.

This new type of memory will be installed on the Storage Cell and used as accelerator in front of Flash memory.

The database node will  access to the Persistent Memory via RDMA with a gain up to 20 x faster access latency.

Oracle is developing the more and more Remote Direct Memory Access (RDMA) instructions for Cache Fusion and Storage Cell operations in order to offload the database nodes and increase the overall performance.

Stay tuned on Exadata Machine because the next generation will also include BIG architectural change…


Oracle Virtual Machine (OVM)

One curiosity directly collected at Linux Virtualization booth is that even though the next generation of hypervisor will be based on KVM, Oracle will keep calling it OVM and of course the current OVM product based on XEN (OVS, OVM) will still be in use by many companies.

How possibly the customers can get confused ?!?


With this I finished, although there would be much more to write.