Thanks to VMware’s
recent $1.26 billion purchase
of Software-Defined-Networking (SDN) leader Nicira, and their new marketing push
on the Software-Defined-Data-Center, everyone is running around trying to attach
themselves to Software-Defined-Anything (SDx). This is as true for the storage
market as it is any other segment of the technology ecosystem. It is a safe bet
that there are a lot of storage companies, both old and new, scurrying around
trying to figure out how to maneuver “Software-Defined” into their
messaging.
This whole SDx concept is built on the idea that all
virtualized data center resources (e.g. server, storage, networking, security)
can be defined in software. These resources are then abstracted into a
higher-level control plane where they are dynamically provisioned out in support
different applications and/or services. The reason this is called
Software-Defined is because we are at least two layers removed from the physical
hardware at this point and all management, orchestration and provisioning of
these services has to be done in software.
As it relates to storage, Software-Defined-Storage (SDS) is
enabled by lower-level storage systems abstracting their physical resources into
software in as dynamic, flexible and granular a manner as possible. These
virtualized storage resources are then presented up to a control plane as
“software-defined” services. The consumption and manipulation of these storage
services is done through an orchestration layer like VMware, CloudStack or
OpenStack. The quality and breadth of these services are highly dependent on
virtualization and automation capabilities of the underlying hardware. More
precisely, the control plane’s effectiveness is dependent on the virtualized
resources it is presented from the layers below it. Without the granular
abstraction of physical storage resources, and APIs to define, flex and apply
policy to these resources dynamically, the control plane is limited in the
services it can provision out to virtual machines or applications.
As you can see from the description above, SDS is a combination
of virtualization, abstraction and control. A storage system by itself is not
SDS. Storage is a supporting element for anyone looking to manage their
infrastructure within the “Software-Defined” framework. There will be a lot of
vendors trying to muddy the waters between Software-Only storage and
Software-Defined Storage. No matter what anyone tries to tell you, they are not
the same thing. Software-Only storage is still requires hardware. The fact that
it is sold as software-only is more of a go-to-market strategy and packaging
decision than a technology decision. Meanwhile, SDS is a higher-level framework
for the orchestration, provisioning and consumption of storage.
In a storage system properly architected to support SDS, all of
the management of system resources is done through software. These resources are
then presented up to the control plane, in a fine-grained fashion, via REST
APIs. These APIs enable the control plane to more precisely provision storage
services to the unique needs of the applications running above it. The APIs are
effectively relinquishing the management of these resources to the control plane
to carve them up and flex as required. This is the way it should be. This
communication layer is essential to supporting Software-Defined-Storage.
In the year ahead a lot of vendors will be quick to claim they
are “software-defined-storage”. However, software-defined storage is NOT a
storage system concept. No single product, system or platform makes up SDS, but
that won’t prevent a lot of people from telling you otherwise. To quickly get to
the signal in this forthcoming SDS marketing storm, here are a few more
questions to ask:
- Ask them if they can abstract and provision not only storage capacity but also performance.
- When they claim they can, ask if it is possible to make an API call to the system for a 100gb volume with 1000 IOPS. Then ask them if they can dynamically adjust this policy on the fly through software.
- Ask them if they have a complete API that allows automation of all storage services so that higher-level orchestration layers can fully exploit the benefits of SDS.
The “Software-Defined” movement has the chance to be a major
leap forward for how infrastructure resources are provisioned, managed and
automated. But a lot of pieces of the infrastructure need to come together to
make the vision of a Software-Defined-Data-Center anything close to reality. As
it relates to storage, in the coming year don’t be fooled by vendor quick claims
of Software-Defined-Storage. Using the questions above, dig beyond the marketing
smokescreen to understand what that really means. You might surprised at what
you actually find.
Author: Dave Wright
Source and Image:
SolidFire
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