Storage Hypervisors: Worth the Hype

Just what are storage hypervisors? There are several companies that claim to have storage hypervisors. Wikipedia states that  a hypervisor is “conceptually one level higher than a supervisory program”. We also know that from our normal use of hypervisors that they manage the underlying resources that a guest uses. Do these definitions work for a storage hypervisor?In short, these definitions work for storage hypervisors as well.

Storage Hypervisors

Storage Hypervisors deliver resources to other systems as required and provide a higher level of control above and beyond our normal storage devices. In fact, storage hypervisors are well known as being able to manage multiple types of underlying hardware regardless of vendor. So in a way Storage Hypervisors act as the single control point seen by those making storage requests. This simplifies command and control of disparate storage devices. There is no need for those making storage requests to care whether the underlying storage is presented as FCoE, iSCSI, NFS, CIFS, or FC to the storage hypervisor, as the storage hypervisor presents in its own form.

Storage Hypervisor

Storage Hypervisor

Many of the modern storage hypervisors sit either as a physical device or a virtual device between the work loads they are serving to and the storage underneath them that generally come from disparate hardware and capabilities. Many storage hardware vendors may also have their own storage hypervisors but are geared to work with mostly their own hardware, think IBM San Volume Controller, which is interesting way of adding high order storage functionality to underlying IBM storage components. Or they could ship as software that either installs on a physical machine or as a virtual storage appliance. In addition, storage hypervisors can do many different things:

  • Augment existing storage with higher order functions such as VAAI, VASA, Deduplication, Replication, Mirroring, etc. Datacore SanSymphony v9 falls into this category by providing VAAI support as well as increased replication and redundancy in an N+1 configuration, which is improved from just two nodes with previous versions.
  • Optimize existing storage for specific workloads by providing a workload optimized file system. Virsto falls into this category for virtual desktop workloads.
  • Gateways to other services such as cloud storage. Twin Strata falls into this category with the ability to provide a single interface for accessing various forms of cloud storage.
  • Aggregate existing forms of storage into just one storage entity such as local, and remote storage functionality. VMware’s Storage Virtual Appliance and Microsoft’s Hyper-V storage functionality both provide this type of storage hypervisor.

Is there one storage hypervisor that fits the entire set of functionality? Perhaps, but the real reason to use one is to aggregate existing forms while either augmenting or optimizing storage workloads. Datacore provides much of this functionality as does Falconstor and several others. The key element is whether they are general optimizers (by adding a huge amount of memory which is used as read and write cache to the storage hypervisor system) or specific optimizers such as ones that create specific use case filesystems.

Conclusion

No matter how you look at your virtual and cloud tenancy you most likely are looking to optimize your storage in some form regardless of what is under the covers. Perhaps it is time to review the current batch of storage hypervisors to determine if they fit your needs? But first decide do you need to augment, optimize, aggregate, or provide a gateway service to your existing storage network? Or are you looking to provide even more security as we discussed previously?

Edward Haletky (364 Posts)

Edward L. Haletky, aka Texiwill, is the author of VMware vSphere(TM) and Virtual Infrastructure Security: Securing the Virtual Environment as well as VMware ESX and ESXi in the Enterprise: Planning Deployment of Virtualization Servers, 2nd Edition. Edward owns AstroArch Consulting, Inc., providing virtualization, security, network consulting and development and The Virtualization Practice where he is also an Analyst. Edward is the Moderator and Host of the Virtualization Security Podcast as well as a guru and moderator for the VMware Communities Forums, providing answers to security and configuration questions. Edward is working on new books on Virtualization. [All Papers/Publications...]

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2 Responses to Storage Hypervisors: Worth the Hype

  1. July 13, 2012 at 4:30 PM

    Great to see this overview of the current state of storage hypervisor approaches. One additional note on Virsto – their solution installs as a virtual storage appliance for vSphere environments and as a filter driver for Hyper-V in each host, and manages the heterogeneous back end storage (any heterogeneous block storage including SSD as a Tier 0) as a pool of capacity. It optimizes ANY virtualized workloads, not just VDI, although the IO blender and writes are especially intense in that use case. It also is the only storage hypervisor to include Per-VM snapshots & clones instead of dealing with LUNS. Transparent management through vSphere or System Center VMM so maintains current workflows, just improves VM performance by 10x while using 90% less storage.

  2. Chris George
    October 22, 2012 at 2:32 PM

    Good article. I would add that when selecting a storage hypervisor keep in mind a few points:
    +Make sure it is from an independent software provider with no bias for specific hardware manufacturers.
    +The world is not all virtual and VMDK based, make sure it can run on physical or virtual servers with VMware/Hyper-V/Xen… – or a combination of all – to match your needs.
    +Supports advanced features like Auto-tiering that work enterprise-wide, across Flash/SSD, multiple vendor storage hardware platforms and works with both virtual and physical worlds
    +Can harness the latest CPUs and Memory to optimally cache and add and accelerate performance
    +Is feature rich.
    Suggest a good way to evaluate is to actually download a copy and try it, of the vendor says you can’t download it is probably hardware and not software -hint, hint;-)

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