Storage management is a mundane topic; one too dry even for most seasoned IT and storage administrators. However, it appears to be getting interesting again. This means that things are changing, thus creating opportunities for vendors to gain leverage and IT personnel to rethink their approach to the topic.
A brief history of storage management reads something like the following:
We are currently moving from stage 4 to stage 5, in that hypervisor management tools are subsuming storage management. With organizations of nearly every size using hypervisors extensively, the shift will have implications both for vendor and IT administrators.
Yes, history often repeats itself, although with a twist and it appears to be happening again. The variation with the new management paradigm is that modern systems are now logical constructs, which are built from virtual components. The “hypervisor” is the new computer and is quickly becoming the center for all IT.
The more trendy term is “Software Defined,” which is really just a euphemism for vendors selling the same software that existed previously. Only now it’s running on standard hardware and often with a hypervisor inserted into the stack.
For the two leading hypervisor vendors (VMware and Microsoft in that order,) the vision for a modern datacenter features the hypervisor as the de-facto center of IT.
The hypervisor management tool-set for VMware, which includes vCenter and other tools like vCenter Operations Manager, envisions VMware as the primary vendor coordinating administration of system resources, including storage.
Likewise, the management vision from Microsoft centers on System Center and the multiple components of that environment, most prominently Virtual Machine Manager (SCVMM). Thus, SCVMM is the primary management tool for Hyper-V and likewise includes management of all resources including storage.
To many people, using the words “Microsoft” and “Standards” in the same sentence is the definition of an oxymoron. However, Microsoft has been promoting, using and adopting standards-based technology to a much greater degree over the past decade. Perhaps nowhere is this truer than in the area of storage management.
Microsoft was one of the early promoters of using CIM as a technology for management and began by using it for their server management tools. With the SMI-S standard being a specific extension to CIM, Microsoft also adopted SMI-S as a storage management tool. However, until very recently that fact was neither well known nor well exposed.
With the advent of SCVMM 2012 and the more recent SCVMM 2012 R2, the use of SMI-S and CIM-XML has become very prominently featured as “the” interface for storage management. This methodology features SCVMM as the interface to provision, allocate and hence “manage” storage resources. All capabilities are derived from SMI-S version 1.4 capabilities, with all supported storage looking rather homogenous.
VMware has been a juggernaut in the hypervisor world. They have been so successful that the VMware hypervisor was nearly ubiquitous in enterprise environments until Microsoft got serious about Hyper-V.
With their significant lead in hypervisor technology, VMware has expanded rapidly to create a portfolio of value-add management products. Now, VMware is focusing on adding storage management into their management suite. However, perhaps due to the “gentle” guidance of their paternal owner, VMware is taking a somewhat different philosophical and technical approach to storage management.
VMware’s vision is less about rigorous storage provisioning from a hypervisor management console than Microsoft’s. In VMware’s vision, storage capabilities and management should be more like “hints” and suggestions; the actual implementation is left up to the individual vendors.
Specifically, VMware has developed vSphere APIs for Storage Awareness (VASA), which will operate in conjunction with a new interface known as Virtual Volumes (aka vVols). While VASA has been implemented for nearly two years, its use has been extremely limited. With the upcoming release of vVols, a complex in-band management interface with in-band management over multiple protocols is used.
In many ways, this is a more flexible approach, enabling storage vendors to provide more value by working with VMware. However, there will be significant issues to overcome in the short term as the interfaces are implemented.
In many ways, the approaches taken by Microsoft and VMware fit their customer bases well. Microsoft’s approach demands more conformity from their storage partners. The SMI-S 1.4 specification is well documented and well understood by many. This will enable Microsoft to carefully control the user experience of SCVMM managing a storage system, with little variation on the storage provider side. This suits less complex environments, where IT generalists require the ability to make operational changes in very predictable ways.
In contrast, the VMware approach presents more challenges for IT users and storage vendors to implement an entirely new set of interfaces. Not only do the interfaces need to function, but the value in the approach must be obvious to both IT users and storage vendors. VMware no longer has the luxury to arrive slowly at a working implementation. Microsoft, SCVMM and SMI-S are now breathing down VMware and vVol’s neck.
The race is on and the good news is that there is room for both approaches if they work well. If not, the implications go beyond storage management and could impact the entire hypervisor eco-system.