As a storage marketer in a vendor, there is always a lot of pressure to determine the category you are in, so you can clearly lay out your value proposition to customers. It also helps you define your competitive set. If possible you want to define a category because being identified as a first mover and controlling a category definition is gold dust. Well in storage we are blessed with a plethora of category definitions and lately it seems like everyone wants to be a part of them all.
As I mentioned in a previous blog I was a participant in a recent interesting CrowdChat on the emerging category of Server SANs. You can find my original post here. During the debate it was clear that there are a lot of interesting takes on the definition of Server SANs and those bleed into the broad definition of Software Defined Storage and the definitions of Converged Infrastructure, Converged Storage, and vSANs. Wikibon has taken a cut at defining the Server SAN. I am not sure I agree with it all, but to move the discussion along I thought I would expand on their initial take and broaden the discussion. I am as interested in a set of definitions that can be understood as anyone else. As a Zoologist I know the power of having a good taxonomy.
Let’s first take a cut at some definitions for some of the most used terms in current vendor marketing materials. (These are my takes, you can find others on the web and I reference some at the end of the article)
Software Defined Storage – a Storage system created from software that runs on an industry standard server. To be truly software defined all of the storage functions and data handling (e.g., RAID, compression, deduplication) need to be part of the software stack. To be truly software defined the platform should be delivered as software and not as an appliance.
Note:-you can find the wikipedia entry here
vSAN – A highly available storage system that can be built from running storage software as a virtual machine appliance.
Converged Storage – A Storage Appliance that is built on an Industry Standard Server base. There are really two separate categories within this. 1) Storage that uses an unchanged Industry Standard Server base and standard Ethernet networking with all storage data handling done in software. 2) Traditional Storage platforms that use hardware based RAID controllers or other offload engines for elements of the storage data processing, or uses a less accepted network protocol (e.g. serial ATA). There are very few traditional storage platforms left not using X-86 processors as the underlying technology. Equalogic and the NetApp products acquired from LSI come to mind as examples of non-converged storage.
Note:-You can find the Wikipedia entry here
Converged Infrastructure – A standardized Infrastructure with a common management framework that crosses, Server, Storage and Networking.
There are other technologies in play that can be confused with this so let me give my simple attempt definitions in the table below. I do not claim these to be definitive (I have not found a generally accepted set of definitions). I am using this as a way to differentiate technologies and facilitate discussion.
Note:-You can find the Wikipedia Entry here
Server SAN - No this is not a Japanese Server. It is a single product, that delivers both server and SAN functionality. That being, it can run the apps that you run on your servers today in virtual machines, and it also provides a highly available storage backend that delivers typical storage functionality.
Hybrid Storage – A storage appliance that blends hard disk drives and solid state into a single solution.
Note:-Most storage solutions can be called hybrid by this definition. “True” hybrid vendors will state that this capability should be designed from the ground up for efficiency and that the movement of data between HDD and SDD should be based on caching. These purpose built hybrid systems often cannot be purchased without SSD.
You will notice from these definitions that there is certainly overlap.
Figure 1 Overlap of Storage system definitions.
Note:-Traditional Storage systems not within the above definitions such as Dell Equalogic are not included.
Note:-Hybrid storage is not included as a category in this map although a popular term. All of the above categories offer hybrid storage solutions.
From the diagram you can see that a vSAN is also a Server SAN and Software Defined Storage. There are many other overlaps in the definitions. Let’s look at some examples of these technologies and break these categories down further:-
|
Category |
Type |
Examples |
|
Software Defined Storage |
Hyperscale Distributed DAS |
Facebook and Google infrastructures. |
|
Scale-Out Clustered Storage Software |
Gluster, Ceph, OpenStack |
|
|
Packaged Storage software stack |
Nexenta (and other ZFS) |
|
|
Virtualized Storage Software Appliances (vSAN) |
HP StoreVirtual VSA, Datacore, SANSymphony-v, SANBOLIC, VMware vSAN,StorMagic SvSAN |
|
|
Cloud-based storage |
Amazon S3 |
|
|
Converged Storage Appliances |
Traditional Storage based on X86 Architectures |
EMC VNX, NetApp FAS, HP 3PAR, HP StoreVirtual, Dell Compellent, |
|
All storage and data handling functions performed in software |
||
|
Converged Infrastructure |
Systems that combine software, server, storage and networking technologies into a single integrated solution. |
Oracle Exadata & Exalogic, |
|
Systems that combine server, storage and networking into a single manageable infrastructure upon which to build applications. |
VCE Vblock, HP Converged Systems, Cisco UCS |
|
|
Server SAN* |
Appliance Solutions* |
|
|
Software Only Solutions* (vSAN)** |
HP StoreVirtual VSA, Datacore SANSymphony-v, SANBOLIC, VMware vSAN, StorMagic SvSAN |
|
|
Data Systems* |
Ceph, Openstack, Gluster, Amazon Web Services, Microsoft SMB3 |
*I used the Wikibon definitions of the Server SAN
** vSANs can also credibly be placed in the converged Infrastructure bucket.
Examples are not exhaustive. They are meant to be illustrative.
Now with examples placed against the definitions we can see that a number of products fit into multiple categories. This is not ideal when building taxonomy. In Biology, an Ant cannot be an Arthropod and a Chordate, because those are two distinct Phyla. In technical marketing we seem unable to even agree what Domain some technologies are in. It is the world in which we live. As a vendor claiming to be “Software Defined Storage” or “Converged Infrastructure” or placing yourself in any other category becomes an important tool to help highlight your value and competitive set to a target customer. As we can see at the moment the proliferation of definitions does not help provide customers with the clarity they want and deserve.
I don’t claim to have an answer. There may not be one. However a healthy debate on this is needed. I am interested in your thoughts. If we humans can work out a system that applies to millions of species maybe we can find one that applies more simply to technology and in this case storage.
Update (03/06/2014) -VMware has just annjounced availability of their vSAN and claim it to be a vSAN, software defined storage , and converged infrastructure. All are true. It will be interesting to see if this enhanced oush by VMware will accelerate adoption of more vSANs and how the market plays out between the vSAN vendors who have been around for a while and the VMware implementation which is built into the hypervisor. Have the current vSAN vendors missed their opportunity now VMware is fully in the market or will this announcement float all boats? Time will tell.
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