A big challenge for a startup in the storage space is catching up to the legacy vendors in terms of features, with one of the most critical and apparently most difficult to complete being site-to-site replication. This feature allows the storage system to better protect itself from an outage at the primary data center. Coho Data Systems is set to fill in this gap with an eminent upgrade to their storage software DataStream.
Coho Data Systems produces a scale-out storage system designed to support numerous, mixed workloads. As we covered in the article “Software Defined Networking For Better Scale-out Storage” Coho Data uses a unique blend of software-defined storage and software-defined networking. When these technologies are combined, they can overcome some of the challenges that high performance scale-out storage systems encounter.
As a result their storage systems provide highly flexible, highly reliable and highly cost effective solutions that can support a wide variety of workloads. The eventual goal of the Coho Data storage system is to stop storage hardware sprawl, allowing the data center to truly consolidate on one storage system for all environments.
Two of the key requirements of a storage system that promises this level of consolidation is that it must be reliable and durable. Coho has had very strong internal data protection since its initial release, and now the latest release of DataStream completes the picture by providing external protection in the event of a disaster.
A Better Site-to-Site Replication?
As I mentioned above, Coho already provides synchronous replication between nodes, but new site-to-site replication feature extends this capability with an asynchronous data path. It leverages their scheduled snapshot feature to copy changed blocks to a remote storage cluster, asynchronously. An important function is Coho’s ability to perform replication at a virtual machine level of granularity instead of blindly replicating complete volumes.
They also integrated replication directly into VMware vSphere. This means that consistent, clean snapshots and replication data captures can be made via VSS (Windows) or Sync (Linux). But Coho’s snapshots are storage system specific, not VMware specific, meaning that other non-VMware workloads could be supported.
The replication stream is also kept secure thanks to 256-bit AES CBC cipher encryption. And, to help with bandwidth utilization, the data being transferred is also compressed.
The secondary Coho system does not need to be a box sitting idle at a DR site either. They support an active – active replication model, which means the secondary site could be another office that can use the “DR” Coho system as their primary storage.
Coho Data Systems claims that their storage system can support a variety of workloads thanks to Coho’s unique integration of software-defined networking with software-defined storage. It is possible for a data center to have a single Coho storage cluster supporting all operations. As a result, site-to-site replication was a critical feature for them to provide. But they did more than “hit the checkbox” here. They have provided several relatively unique features like:
- Asynchronous, periodic, snapshot-based replication
- Active – Active site support
- Virtual Machine granularity
- Bandwidth throttling