It’s come to my attention that pretty much every storage manufacturer is trying to imitate NetApp’s thought leadership and keeps announcing “Unified Storage” products. Everyone can do it now, it seems 🙂
Now, this post is not going to be bashing them or claiming they don’t work.
This post is about arguing what “Unified Storage” really means. And, more importantly, whether you should care about the differences.
Now, NetApp has been shipping Unified Storage for 8+ years now, and has shipped 150,000 Unified Storage systems to date. See here and here. So, I’d think nobody can argue that NetApp has quite a bit of experience in the technology and, indeed, were the very first to do it. Depending on your definition of “Unified”, NetApp may still be the only one doing it, but read on.
The crazy success of NetApp’s Unified Storage (just look at the company’s growth) has forced the other vendors, who initially dismissed the concept, to take a harder look – imagine that, customers actually like the idea of a Unified Storage System!
Here’s how most (if not all) other vendors approach “Unified Storage”:
- Start with your legacy Fiber Channel Array, use that to serve FC and maybe iSCSI. It’s probably a decent box, no reason to re-invent the wheel.
- Connect some kind of Windows, Linux or UNIX server(s) to it that will then serve CIFS and NFS and maybe iSCSI (this is the NAS part)
- Replicate them using different mechanisms for the FC and NAS parts
Pretty simple, really. You end up with the base legacy array, plus more boxes on top (ideally 2+ to ensure redundancy, plus some of them need an extra box or two called a “Control Station” in one implementation).
It all works – after all, it’s just like putting servers in front of your storage, you’re doing that anyway. You are able to serve FC, iSCSI, NFS and CIFS out of the same rack. If we assume that the rack is the termination point for the cables and that you don’t care much about exactly what happens within. So, most C-level execs are OK with it – the rack can serve out all those protocols, ergo the “Unified Storage” claim seems justified.
Here are some potentially business-impacting issues with this approach:
- Aside from a couple of exceptions, the add-on boxes used by the storage vendors to add the NAS protocols aren’t even made by that vendor (neither the OS nor the hardware). Obviously that raises some concerns with interoperability, manageability and the longevity of whatever NAS vendor was chosen. Support is now maybe not as robust since you are relying on using tech someone licensed from someone else.
- Replication gets complicated since you need to do it a few different ways depending on what protocol you’re replicating.
- Patching is more time-consuming since, apart from the legacy array, you need to also patch all the NAS paraphernalia.
- Management is frequently totally separate and laborious – you might have to take care of the legacy array separately from the NAS part
- Certain important features are only available to one part of the solution (file-level single-instancing/dedupe, for example, only available for CIFS and NFS and not for iSCSI or FC).
- And, finally, what I think is the biggest problem: Space allocation is split between the FC and NAS parts and you can’t reduce one to increase the other. For instance, if you started with a 50/50 split, once you’ve allocated the space to the NAS (that always has its own Volume Manager and now owns that 50% chunk of array space), and you realize you’re only using 10% of that space after all, you can’t go ahead and return the remainder of the space to the FC part. This can cause serious inefficiency, inflexibility, cost and manageability issues.
The NetApp approach
NetApp decided to do things a bit differently. Maybe by virtue of how the original systems started out, it turned out it was easier for NetApp to effectively create what is effectively a protocol engine. Maybe “Protocol Engine with Integrated Disk Control, Space Efficiency Technologies and Protection” is more appropriate than “Unified Storage” but it’s a bit wordy…
Effectively, a single NetApp box, without external hangers-on, allows you to:
- Connect using a variety of methods – FC, 1GbE, 10GbE, FCoE
- Use the proprietary NetApp RAID-DP protection for great performance and better protection than RAID10
- Provision FC, iSCSI, CIFS and NFS out of the same pool of physical disk space
- Reclaim space from FC, iSCSI, CIFS and NFS and put it back in the pool of space
- Deduplicate FC, iSCSI, CIFS and NFS workloads
- Perform application-aware replication regardless of protocol
- Take application-aware snapshots regardless of protocol
- Clone VMs, DBs and indeed, anything you like, without chewing up space and without impacting performance
- Virtualize legacy arrays and impart on them the NetApp features
- Perform workload and cache prioritization
- Auto-tier hot blocks to gigantic cache to increase speeds (at a super-efficient 4K granularity)
As you can see, everything happens within one system, there’s no separate RAID controller or NAS box or replication box. And, like it or not, that’s a pretty impressive list of capabilities that a single architecture provides.
The potential business benefits with a true Unified Storage system:
- Single product, single OS, single architecture – you’re not relying on the marriage of completely different boxes.
- Better reliability, less things to break.
- Better support – no finger-pointing, it’s a single system from a single company.
- Consistent replication – one way to replicate things, yet still application-aware for 100% recoverability, improved CapEx and OpEx.
- Management simplicity – lower OpEx.
- All performance-enhancing and efficiency features are available to all protocols – Improved CapEx.
- There’s no dichotomy between FC, iSCSI and NAS space – allocations are fluid – Improved CapEx and OpEx.
- Protect your existing investment by virtualizing existing legacy disk arrays – improved CapEx and OpEx.
- Overall lower OpEx and CapEx – in addition to the significant space-saving features (avoid purchasing as much storage long-term), there’s significant cost avoidance since you potentially don’t need to purchase: Backup software, deduplication appliances, replication appliances, fileservers, OS licenses.
So, should you care how “Unified Storage” is architected?
Beyond the philosophical debate (one box vs multiple), given what you read, what do you think? I believe that the multi-box approach has some inherent drawbacks that are difficult to overcome. Comments welcome as always.