Lightning AKA VFCache

VFCache (Very Fast Cache) is the final product name for the project that was called Lightning.  It turns out that this offering is nothing more than a PCIe SSD card for servers (not all servers mind you, but at this stage quite a few).  The initial offering combines with software to act as a very fast read cache to the host.  In Windows terms, this is implemented as a filter driver that sits above the STORPORT driver in the I/O stack, with similar implementations on Open Systems platforms.  The software component of VFCache tracks I/O and caches reads in order to speed up future I/O requests without needing to go to external disk.  Writes to disk are not cached by VFCache and EMC tried to make a virtue of the fact their product acts as a “write-through” cache, meaning I/O writes have to be committed to physical disk before the cache acknowledges them to the host.  Rather than being a benefit, write through mode in this instance is more likely to make the cache less effective by polluting the cache with writes that can’t be released until confirmed externally.  When there’s a difference in I/O if microseconds versus milliseconds, then this difference really matters.  However, I don’t think this is a design flaw, merely a placeholder for the future, as I’ll discuss later.

Disappointingly for EMC, VFCache 1.0 really is a 1.0 version in terms of feature support.  Within VMware ESXi for instance, the card installs with a device driver that only allows the cache benefits to be used when the filter driver is deployed into each ESXi guest, so it’s not simply a case of insert the card and off you go.  Moreover, the VFCache appears as a DAS device within VMware and so can’t be used in conjunction with vMotion.  For many organisations this is a huge omission as there’s a big correlation between high performance and high availability; the lack of vMotion isn’t acceptable.

The Competition

We can’t go any further on the VFCache discussion without mentioning the competition and in one of the presented slides, EMC paid homage to the market leaders, Fusion-IO.  Their ioCache product already accelerates VMware ESXi and Windows 2008 environments, using a similar hypervisor plugin approach.  ioCache already offers double the capacity of VFCache and it’s likely Fusion-IO have larger capacity cards in the pipeline as they already offer a range of SLC and MLC flash devices.

Thunder Follows Lightning

Surely Hitachi must be enjoying the irony of EMC choosing product code names based on already defunct HDS hardware (Thunder and Lightning were the mid-range and Enterprise products respectively that preceeded AMS and USP).  The next product announcement moves the flash-in-server story forward and explains how this technology is limited in terms of availability.  The move to centralised SAN environments was done precisely to fix the issues that occur with server-side SSD today.  Data is locked into the server, is difficult to expand (requiring downtime and physical intervention) and is isolated from access if a physical failure of the server should occur.  So, step up Project Thunder, EMC’s purpose build all-flash array.  This device allows multiple servers to share data across what EMC are calling the “server-area network”.  What they mean is a physically local, high-speed interconnect (such as Infiniband or Rapid-IO) between the server and a fast all-flash storage array.

The interconnect technology between devices already exists today (as already mentioned) but placing it into the server and using this for shared storage presents more of a challenge.  Where Lightning was a simple Filter Drive, Thunder will require deeper integration in order to manage consistency across all connected servers.  This isn’t something that comes new to EMC – think of how VMAX nodes interconnect and you have the model already there.  However, the implementation may require closer co-operation with server vendors than EMC can achieve, those same companies they are already in competition with for storage – IBM, HP and Dell.  This could mean Thunder becomes a VCE only product or is severely restricted when deployed in other manufacturers hardware.  We will have to wait and see. (Side Note: This also means that other all-SSD array manufacturers could become more attractive to HP, IBM & Dell as acquisition targets – check out here and here).

The Competition

Let’s not forget that dedicated all-flash arrays are already out there.  Recently I’ve discussed Pure Storage and SolidFire and there’s also Violin Memory, who have been going at this market for quite some time.  They already have the SSD array technology to a mature level including support for Infiniband; all that’s needed is a software driver to bring clustering to their products.

Futures

What can we expect going forward?  There are lots of gaps the product releases we’ve seen today.  Lack of vMotion support and no write-back cache to name only two.  The question we should be asking is what could be delivered in the future.  EMC have access to every piece of the I/O stack, from the hypervisor, the multi-path driver, through to the array.  Using PowerPath, EMC can develop more intelligent algorithms that choose whether to cache I/O locally in the server/hypervisor, destage to the array, leverage pre-fetching from disk and other clever ways to squeeze the best level of performance out of the hardware stack.

Conclusions

EMC have ratified both the PCIe SSD and dedicated flash array markets with their announcements of Lightning and Thunder.  At this stage they are bringing only “me too” products to the market, with other vendors out there having already delivered more advanced technology than being announced today.  However EMC have two big advantages; (a) they are a huge organisation, with access to the majority of customers in the market and a great marketing team.  They have the ability to place their products into customer environments and use price as the main differentiator (b) they have a huge R&D budget and never stand still on product development.  Today’s 1.0 releases will be superseded within months and address some of the shortcomings we can see today.  The future battle will not be over the hardware, but the software that integrates I/O in the server to I/O on the array, delivering the benefits of local flash with the safety of external storage.  The eventual winner will be the vendor who gets that software and hardware integration right.

Related Articles

You may be interested in the following related articles from this and other sites.

• Fusion-IO Shares Tumble as New Entrants Prepare to Enter The Market
• Emulex – Evolution of the HBA
• Solid State Arrays: SolidFire
• Solid State Arrays: Pure Storage Inc
• Who Will Be The First Solid State Array Vendor To Be Acquired?
• HP & Violin?
• Enterprise Computing: Violin Memory Inc Release New All-SSD Array
• EMC VFCache (aka “Project Lightning”) Is One Small Step, But an Important One (Stephen Foskett)
• Cache Splash (Storagebod)
• VFCache Means Very Fast Cache Indeed (Chuck Hollis)
• VFCache: Hello World! (…and covers come off Project Thunder) (Chad Sakac)
• My take on EMC’s project lightning (Enrico Signoretti)

This may seem like a bold statement to make, however we need to look forward to where the industry is headed.  First of all, vendors want us to buy their unified hardware stacks; it represents that move back to a consolidated architecture that kept one vendor dominant in the mainframe days – IBM.  “No-one gets fired for buying IBM” the saying goes (or used to go), demonstrating how IBM was seen as the data centre supplier for all things computing in the 70′s and 80′s.  Of course we know that politics within organisations and the cost of IBM hardware eventually broke the monopoly, but the status quo worked well for many companies for many years.

Now, Cisco, EMC, VMware, HP, Oracle and potentially many others want to own your data centre.  They want you bought into their computing stack.  Over time, I suspect many of those same companies want to move you to their cloud infrastructure offerings, even if they don’t offer them today.  This will be both directly and indirectly.  There will be the direct model, where the vendor offers cloud services to you under their name; there will be the indirect model where their technology powers the cloud provider, or is offered as a service.  It’s at this point the 3Par acquisition becomes much more interesting.

3Par already have many customers in the cloud services sector.  In fact they sell their hardware on the virtues of multi-tenancy, reduced cost through thin provisioning, tight integration with virtual hypervisors and so on.  In this growth sector of the industry, cost is a key driver and no end user or company will pay more than they need for storage.  This means Enterprise arrays like those from Hitachi and EMC won’t play a central role in this future, but rather storage devices which provide the highest efficiency will.  Where do all the major players stand?

• EMC have entered the market with a brand new platform – Atmos.  Although withdrawn as a direct service, Atmos continues to be available from partners.  EMC have chosen to use their own technology as the foundation for cloud.  In addition, VPLEX provides the ability to virtualise the storage layer, including federation features that fit well with VMware.
• HP have a strong blade server offering for their cloud infrastructure.  Matrix provides orchestration for the server, network and some parts of the storage layer, however this work is incomplete and doesn’t fit well with the high end XP arrays.  Slotting 3Par into the storage layer would provide a storage platform well suited to HP Converged  Infrastructure.  It means EVA can be quietly dropped and XP can be retained (in whatever future guise) for high end customers (including mainframe) and if required, gradually dropped.
• Cisco have chosen to partner with EMC rather than acquire storage technology itself.  In fact, looking and both EMC and Cisco, they need each other; EMC have no server platform, Cisco have no storage; it’s a mutually beneficial arrangement, a bit like Jack Sprat and his wife.  At this stage, Cisco could have purchased 3Par and provided and end-to-end solution, but clearly that would be a big step and would require kicking EMC to the kerb, something they obviously don’t want to do (yet).
• Hitachi have server and storage offerings, however Blade Symphony is mainly sold in domestic Japan and not widely advertised globally.  They do have the potential to provide an end-to-end offering as Hitachi also sell networking equipment.  Key for Hitachi will be credibility in a market they don’t currently play in.
• IBM should have all the components of a consolidated infrastructure but there doesn’t appear to be a lot of discussion about their offerings.  They appear to have two strategies – Dynamic Infrastructure and Cloud Computing but their offerings aren’t clear.
• Dell clearly wanted 3Par to fit into their medium to high-end storage offerings.  Today Equallogic has successfully met their SMB requirements, but they OEM technology from EMC (CLARiiON and Symmetrix) for the rest.  Acquiring 3Par would remove that dependency and allow Dell to offer end-to-end technology as their own products.
• Netapp have a self-proclaimed unified architecture that does fit well with virtualisation from VMware.  However they don’t own any other parts of the technology stack and so must partner to deliver unified offerings.  Netapp are covering all bases by offering solutions with VMware, Microsoft and Citrix, but none of these could be described as the unified stack other vendors have.
• Oracle already provide an integrated infrastructure based around their Exadata acquisitions and of course all of the Sun Microsystems technology, however I’m not sure many companies would see the Oracle offerings as other than tied directly to their database platform and not for virtualisation.

Overall, 3Par fit the requirements of HP & Dell to provide integrated technology offerings.  The move to the cloud will require leaner and efficient storage products, plus tight integration and orchestration.  It’s all about positioning today for bigger returns tomorrow.

EMC – blogs are run like a military machine; co-ordinating the news relating to new product releases and mercilessly hammering the competition. EMC have more storage bloggers than any other storage company and there are some good ones out there – one of my favourites is Information Playground by Steve Todd, where he discusses the design of Clariion.

Netapp – follows a close second to EMC with lots of bloggers and lots of competitor bashing. I particularly like Alex McDonald’s postings.

IBM – doing a great job running the “resistance“, fighting back against the continual onslaught of Barry (A Burke). Check out Barry (Whyte) and Tony Pearson. I’d like to see more from IBM though, especially their product developers working on DS arrays and XIV.

HDS – A jolly good bloke, but not really a player in the blogosphere. Only Hu contributes regularly, but doesn’t engage in any serious debate.

Sun – quite literally on another planet with their storage strategy!

Dell – bought some toys, but doesn’t know how to play with them. Unfortunately the older boy who could help them play with them has left…

Now there are more companies out there and I don’t think I have any blog links from Brocade, 3Par, Compellent, Emulex, Qlogic, Pillar and others although I may be wrong (it is getting late). Any RSS link offerings gladly welcome – although I might not get around to reading them before my next holiday!