VMware Cloud on AWS

i3en.metal Compression Only

With the VMConAWS 1.12 rollout came a significant enhancement to the already impressive i3en.metal host. With this latest update, we have increased the usable capacity for any i3en clusters by enabling Compression-Only within vSAN. Existing customers will see improvements in real-time as SRE upgrades existing deployments. New Clusters will have the feature enabled by default. With this enhancement, we have discontinued the checksum only configuration.

Why Change?

We are always looking to improve utilization within the service. The new Compression-Only storage efficiency capabilities, introduced in vSAN 7 U1, present the opportunity to provide more usable capacity without compromising on the service guarantee in any way.

VMC on AWS Performance

What about Deduplication?

After all, Deduplication and Compression work in unison on every i3.metal host within the service, so why not here? There are a couple of considerations that made Deduplication inappropriate for the i3en.metal hosts, but the deciding principle was time to recovery. Deduplication is a powerful tool, but it works by comparing a given block to all the blocks that came before, to avoid writing the same data multiple times. This process serializes disk access through the deduplication process. On an i3.metal host, this isn’t a problem. With three capacity drives per cache device, the system balances out nicely, and we effectively doubled usable capacity.


The impact would be much more significant on i3en.metal due to the use of NVMe namespaces. By logically allocating the physical storage, i3en clusters run maxed out disk groups with seven capacity devices for each cache device. By not enabling dedupe, vSAN retains the ability to write to every capacity device in parallel. The additional write throughput is essential to manage the time to recovery with 48TiB of capacity per host.

i3en Compression only

What does this mean to any Virtual Machines?

Nothing. Compression is enabled at the cluster level and is managed by VMware operations. It is transparent to any running workload. A VM running on i3.metal will see roughly the same performance as it would on an i3en.metal. That is not to say that they are the same. The i3en.metal instance provides roughly double the aggregate performance of a standard i3.metal host. But the difference is in how many VMs the host can support, not the performance of a single VM.


With this latest release, the service continues to deliver on its core mission; To offload the everyday infrastructure operations. In doing so, the service frees up those cycles so that customers can focus on their workload.   This latest enhancement points to the power of that partnership.  Without any customer action or thought, every VMware Cloud on AWS i3en.metal cluster will gain additional usable capacity with the 1.12 upgrade.  A trend we hope to continue in the future!


To view the latest status of features for VMware Cloud on AWS, visit https://cloud.vmware.com/vmc-aws/roadmap.