Database High Availability Simplified

SkyCluster vs. VMware Cloud

for running Oracle RAC on AWS

FlashGrid welcomes VMware Cloud on AWS as an alternative solution for running Oracle RAC on AWS. However, for customers who primarily use AWS native EC2 environment SkyCluster offers a much more practical solution. And even for those customers who use primarily VMware Cloud on AWS, SkyCluster offers substantial advantages that justify running Oracle RAC clusters in the native AWS EC2 environment.

Below is a comparison of the two solutions. Each item has a link to more details.

SkyCluster VMware Cloud on AWS
EC2 instance types supported i3, R5, R4, M5, M4, Z1D, X1, X1E, and more i3, R5
EC2 instance sizes Any VM size or bare-metal Only full-size hosts
Bare-metal as RAC nodes Yes No
Combining local NVMe SSD and EBS storage Yes No
Native Oracle mechanisms for disk group management and data mirroring Yes No
Read I/O from local disks Yes No information
EBS sizing flexibility Any # of disks of any size 10 to 35 TB per host, 5 TB increments
Single cloud account required Yes No
Single vendor billing Yes No
Deployment automation Yes No
Comprehensive validation Yes No information
24/7 support with Oracle expertise Yes No information
Proven in production use Yes No information
Simple. Flexible. Reliable. Yes ?

Choice of EC2 instance types

Having a wide selection of EC2 instance types to choose from contributes to:

  • More flexibility
  • Higher performance
  • Lower costs

FlashGrid SkyCluster supports over 40 different VM types to choose from:

  • R5, R4: most popular
  • M5, M4: lower memory to CPU ratio
  • Z1D: low CPU core count with high frequency
  • i3: up to 15 TB of local NVMe SSDs per node for max read throughput
  • X1, X1E: large memory and CPU
  • u-6tb1.metal, u-9tb1.metal, u-12tb1.metal: extra large CPU and memory
  • Future instance types as they become available

VMware Cloud on AWS supports only two instance types: R5.metal for use with EBS, and i3.metal for use with local SSDs, which limits the opportunities to size the cluster for optimal price and performance.

EC2 instance sizes

SkyCluster can be deployed on VM instances of virtually any sizes. This allows precisely sizing the cluster to meet the performance and cost requirements.

VMware Cloud on AWS can be deployed only on full-size EC2 instances. This creates major cost overhead unless full instance size is required or other (non-RAC) VM resources also need to be deployed on VMware.

Bare-metal as RAC nodes

SkyCluster supports using AWS bare metal instances as RAC nodes for maximum performance and reliability. Supported bare metal instance types include r5.metal, m5.metal, i3.metal, z1d.metal, u-6tb1.metal, u-9tb1.metal, and u-12tb1.metal.

With VMware Cloud on AWS, RAC must be deployed on VMware-managed VMs, making it impossible to leverage the benefits of bare metal.

Combining local NVMe SSD and EBS storage

SkyCluster allows combining both the local NVMe SSD based storage and EBS storage, thus accommodating both fast and large capacity data tiers.

VMware Cloud on AWS offers choice of either local NVMe SSDs, or EBS, but does not allow combining the two.

Native mechanisms for disk group management and data mirroring

SkyCluster does not introduce proprietary data management or data mirroring code in the data path. All data management is performed by native Oracle ASM (Automatic Storage Manager) with Normal or High Redundancy disk groups, thus eliminating risks to data consistency or integrity.

With VMware Cloud on AWS, data mirroring is delegated to vSAN with RAID-1 or RAID-5, adding an external layer and overhead to the solution stack.

Read I/O from local disks

FlashGrid Read-Local Technology ™ utilizes Oracle ASM Preferred Read functionality to ensure that read requests are served from local storage that is attached to the same node that is serving the request. With 2- or 3-node SkyClusters, each node has full set of user data, and therefore reading from local disks provides the following benefits:

  • Maximizing read throughout
  • Maximizing read IOPS
  • Minimizing read latency
  • Minimizing network consumption

EBS sizing flexibility

With SkyCluster, any number of EBS volumes of any size can be attached to database nodes, providing a very granular method of sizing the storage. Run extra large databases of 100 TB or more. Or minimize costs for small and test clusters with 1TB or smaller capacities.  Resizing storage can be done with no downtime.

VMware on AWS storage is limited to the range of 15 to 35TB per host with 5TB increments, making the solution practical only for a narrow band of database sizes. Users with smaller databases will have to pay high excessive storage costs. Users with large databases might have to provision extra hosts, which increases costs and complexity unnecessarily.

Single cloud account required

Only AWS account is required to deploy and use SkyCluster, reducing management overhead compared to RAC on VMware Cloud on AWS, where both AWS and VMware accounts are necessary.

Single vendor billing

SkyCluster fees are billed by AWS through the AWS Marketplace AMI offering. Using SkyCluster does not require direct billing by FlashGrid, keeping all billing with single trusted vendor, AWS.

With VMware Cloud on AWS customers will need to maintain two vendor relationships, AWS and VMware.

Deployment automation

SkyCluster Launcher generates custom AWS CloudFormation templates for automated Infrastructure-as-Code deployment of AWS EC2 resources, FlashGrid software, Oracle Grid Infrastructure and Database, resulting in

  • Dramatically shorter deployment timelines
  • Eliminating human errors
  • Repeatable process

There is no deployment automation for RAC on VMware Cloud on AWS.

Comprehensive validation

There is a significant difference between a solution working in principle and an actual enterprise-grade validated product. Continuous extensive validation of SkyCluster with various database versions, latest release updates, and Linux kernel updates ensures smooth database operation during the entire life of your applications.

24/7 support with Oracle expertise

SkyCluster is delivered complete with 24/7 support by highly skilled engineers with expertise in both Oracle and AWS technologies. See the FlashGrid Technical Support Services description.

Proven in production use

Multiple enterprise customers use SkyCluster in production for mission critical applications, some since 2017. Read case studies with select customers.

“We had to migrate dozens of mission critical Oracle RAC databases from Exadata to AWS with FlashGrid SkyCluster, and were able to do it without sacrificing performance or availability.”

Rama Kolli, Sr. Director – Database Management, S&P Global Ratings

“FlashGrid SkyCluster provides us all elements needed for running our mission-critical Oracle databases in Azure: storage and networking software, deployment automation, and 24x7 support.”

Jay Wilder, Sr. Director of Software Engineering, Nuance Communications

“With FlashGrid and AWS we can now deploy a new application within two weeks instead of six months, without compromising our availability SLA.”

David Urban, VP Operations, Aria Systems

“SkyCluster for Azure proved to be a reliable solution that is easy to implement and support for us as a systems integrator.”


“With our new virtualized RAC running on FlashGrid architecture we do a 125GB full table scan in 6 seconds. That is an 11x improvement over our previous setup.”

Sam Shiel, Oracle DBA, Simplyhealth

“Implementing Oracle RAC with FlashGrid in AWS is an important milestone in Digital Virgo’s cloud journey.”

Mikolaj Klimek, Deputy Director IT Operations and Infrastructure, Digital Virgo

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