Walk into a technology trade show with a bottle of tequila and a shot glass. Take a shot each time you hear the phrase ‘software defined’, you would need a cab to get back home. The new buzzword is ‘software defined’ and storage vendors are making ways to fit it in. It doesn’t matter whether it is one of those established players or upstarts. If it isn’t software defined, it is not cool.
What is SDS? There are many vendor specific definitions and interpretations for SDS. Industry analysts like Gartner and IDC have their own versions too. Hence I would just say what the attributes and values are expected in general from SDS.
Abstraction: Data pane and control pane are separated. In other words, the storage management is decoupled from the actual storage itself.
Backend heterogeneity: Storage is served by any kind of storage from any vendor including commodity storage.
Frontend heterogeneity: Storage is served to any kind of consumers (operating systems, hypervisors, file services etc.)
SDS is a broker: This was the statement from Gartner. SDS brokers storage services, independent of where data is placed and how it is stored, through software that in turn will translate those capabilities into storage services that meet a defined policy or SLA.
Logical volume managers in operating systems had provided the attributes 1 and 2 since 80s. The cross-platform volume manager from Veritas (acquired by Symantec) brought 3 into the mix with the introduction of portable data containers (also known as cross-platform data sharing disks) in 2004. Other notable examples fitting the requirements 1,2 and 3 are IBM’s SAN Volume Controller (SVC) offering and NetApp’s V-series.
Now let us take a look at the final attribute to fit something in SDS, the broker role. Surprisingly, Veritas Volume Manager (VxVM) meets that requirement as well. Storage services like file service, deduplication, storage-tiering etc. are provided by Veritas Volume Manager independent of where and how it is stored.
Let me elaborate this further to prove this point. VxVM abstracts storage from any array or commodity storage. This is old news. What is new about the latest version of VxVM (part of Symantec Storage Foundation 6.1 powered by Veritas) is that it can now provide a single name space (data service) across multiple nodes without the requirement to have disks shared via a storage area network. This completes the final requirement to fit the attributes required by SDS.
The point of the blog is not to underestimate the significance of SDS, rather to conclude that SDS may already be here depending on your definition and interpretation! Let us think beyond vendor presentations. How is EMC’s ViPR different from what NetApp V-Series had been offering for years? Should Flash be on hybrid array (e.g. Nimble Storage), all flash (e.g. Pure Storage) or close to system (e.g. Nutanix)? Or should you adopt something that gives the flexibility to choose (Symantec Storage Foundation 6.1, pardon my pitch). It truly depends on your business requirements, but I would say that Flash Anywhere might provide flexibility while storage industry is looking for the winner.