Andy told me that they spoke to many, many customers about storage management and usability before embarking on their new project. He told me that the vast majority of customers that they spoke to about storage had the same complaints. These were frustrations around difficulty in refreshing their storage infrastructure as new technologies became available (fork lift upgrades), building silos for certain departments and even applications, not being able to understand the performance and behavior of their storage (storage is a black box), the difficulty in troubleshooting and diagnosing issue end-to-end, and finally having to manage their system via aging management interfaces which were always cluttered and complex. To be honest, these seem to be the same sorts of complaints I hear when talking to customers about storage too, especially the performance, troubleshooting and management aspects. I’m sure many of you agree with this. Andy also mentioned that when he attended conferences and sat in on storage presentations from various vendors, it was all about the IOPS, with very little discussions on what the broader storage problems were, and how these vendors were going to address them.
Andy then told me that he wanted to achieve a number of goals with their new storage platform. First, they wanted to be able to use commodity components in their platform, make it perform like crazy, and then wrap it up in a way that customer could simply plug them into their environment and scale them out in a linear fashion – a bottleneck free architecture. They also wanted to create a management interface which gives all the necessary details to allow an engineer or customer to quickly diagnose any performance problems which might arise. He feels that COHO DATA achieves just that.
COHO MicroArrays and COHO Chassis
First things first – this is not a converged platform, this is storage platform. The platform is made up of MicroArrays. Each MicroArray contains compute, network, disk and flash. The MicroArray may be considered a storage or data hypervisor. COHO claim that a single chassis consisting of two MicroArrays can deliver a predictable 180K IOPS. It is sold as a ‘rack’ configuration, which include a top of rack 10Gb DataStream switch. Using OpenFlow, COHO can manage all of the I/O routing, data placement & load balancing. It is this management at the switch level that guarantees linear performance and low latency as the platform scales. The COHO chassis is the building blocks of the platform, allowing scale out from 1 to 100s of MicroArrays, and thus from TBs to PBs. Scale out is very simple, as the MicroArrays are auto-discovered and configured in a matter of minutes.
Under the covers, COHO DATA have implemented an object store. The platform presents NFS datastores to the ESXi hosts. However, this storage platform is not limited to just virtual machines. COHO DATA have plans to expand this platform to other general purpose storage use cases in the future.
COHO supports a tiering approach to their storage through the use of data policies. You can select a particular data policy when deploying a VM, and using the smarts of the MicroArray, that objects which make up that virtual machine can be placed on different storage components across the platform, including a combination of flash and HDD.
COHO supports application-specific performance policies in their own management UI but Andy mentioned that they are currently exploring using VASA for enabling this configuration through vCenter. However, they feel their implementation is much superior as it lets you set a profile at this finer granularity and even change it dynamically on a per-object basis, something that VASA does not allow you to do right now.
Object Placement and Layout Policy
COHO has replication technology based around the concept of replication domains. In other words, if there is a failure of a MicroArray, chassis or rack, the replication domain can ensure that there is still a full copy of the data available. We mentioned that objects can be placed on different storage components across the platform – this is based on the ability to store virtual machine as objects. These object are made up of multiple chunks (in many ways, there is a similarity to how VMware’s Virtual SAN stores virtual machine objects). Each object has a mapping table which allows the chunks of the objects to be mapped from many places, which allows the data placement algorithms to keep that linear performance and low latency. And so while the object on-disk layout might be made up of a mix of flash and disk, there is one set of metadata for the complete object. This make is very simple for COHO to do storage services like snapshots, deduplication and so on. However, it was pointed out that deduplication or compression is not in the initial release, but it is something that is on their road-map. Snapshot is in there, and it is done at the object level, i.e. virtual machine disk level (VMDK).
I also asked Andy about a DR solution, i.e. allow replication of objects across sites. I guess this could also be a building block for a stretched COHO solution. Andy said that this functionality will not be in the initial release but is something that they have on the roadmap.
I then asked Andy a number of questions around vSphere interoperability.
SRM/vR – planning to have interoperability with SRM shortly in the v1.5 release next year.
VDP/VDPA – planning to have interoperability with VDP/VDPA with the v1.0 release later this year.
VAAI – COHO will have support for the VAAI-NAS File Cloning primitives in v1.0 and are planning to support the other primitives shortly thereafter.
UI Plugin – COHO’s DataStream Management UI is currently standalone, but they’ve already started working on integration into the vSphere web client and plan to release this early next year
What about the price?
I put this question to Andy. The response was that each block/chassis with 2 x MicroArrays contains 39TB, and that the price is $2.50 per GB. If I extrapolate that out, that looks like just under USLP$100K per block/chassis. After querying this with Andy, he confirmed that my math was correct. The SDN-enabled DataStream Switch is sold separately for USLP$30K. It is a 52 port 10GbE Switch and can be used to scale 6-8 DataStream Chassis into an 300TB+ cluster of MicroArrays. Customers can scale by adding single MicroArrays at USLP$50K each.
Where can I learn more?
Visit cohodata.com for more information.