I believe in stupid questions.  They are born from a lack of knowledge and can’t we all relate to that?  For instance, a coworker recently asked me: “With VMware’s vSphere 6 coming out, how does that change things for VPLEX?” To which I replied, “Not much.” Because when you ask a stupid question, the person who answers is allowed to be deliberately obtuse.  That’s a rule I just made up.

 

The real answer is that, really, not much changes.  The three big items that launched with vSphere 6 were VVOL support, Long Distance vMotion, and expanded Fault Tolerance support.  I’ll get Fault Tolerance out of the way right now.

 

The new Fault Tolerance changes in vSphere 6 are amazing!   Finally you can run FT on your mission critical VMs, on VM’s of substance!  But excellence comes at a price, and today that price is distance.  FT is not allowed to run in Stretched Metro environments.  In VPLEX Local environments, FT runs great.  On VPLEX Metro environments FT is ruled out.  It’s as simple as that.

 

Since FT was ruled out, what interested my coworker were VVOL support and this new vMotion.  I’ll start with VVOLs.  For many people, while they know about VVOLs, they may not really get it if you know what I mean.  I will now attempt to greatly overly simplify what VVOLs are, and why they are important, in a general hand-waving sense.  The two aspects of VVOLs that are important are 1) per VM storage and 2) control path interface with storage arrays.  For each VM you now have 3-5 LUs that hold things like the VM configuration, running state, and of course the VM data.  This collection of LUs can then move or grow or shrink or be protected on a per-VM basis.  The control path aspect means that there is a well-defined way for vSphere to now tell the storage array what needs to be done for any particular VM.  All of this leads to a policy-based style of management.  Setting up a new VM? Great! Here is our menu. Would you like flash storage with that?  May I also recommend the salmon?  It’s just in and very fresh.

 

So what’s the plan for VPLEX and VVOLs?  The short version is we’re working on it.  The slightly longer version is that VPLEX has to work with many other storage arrays, and to do that with VVOLs we need to utilize the VVOL control interfaces of those storage arrays ourselves.  Once they have VVOL support, we can build on top of that foundation.  This means that VVOL support for VPLEX is coming in the future, which means we don’t support it today (bypassing a stupid question there with a stupid answer).  Should the delay in VVOL support cause you sleepless nights, an increase in anxiety, and a constant urge to pop a Valium (thank you Dr. Smith)?  Not really.  The concept of VVOLs is just getting started and VMware is continuing to grow and improve on the VVOL idea.  In the meantime you can continue to use VPLEX as you always have to support your VMware environment with VPLEX continuous availability with VMware High Availability, metro stretched clustering, instant vMotion, and load balancing between sites.

 

Now that those topics are out of the way, can we talk about the elephant in the room?  I’m going to assume that most of you don’t actually have an elephant in the room, and instead talk about Long Distance (LD) vMotion and VPLEX.  For those of you who haven’t been attending VMware technical conferences, LD vMotion allows vSphere 6 to (wait for it) vMotion individual VMs over extremely long distances.  Previously with vSphere you were limited to metro distances which equate to about 5-10 ms of roundtrip network latency between sites.  That usually means within a city or between relatively geographically close cities.  With LD vMotion you can move a VM across continents!

 

I imagine those of you who have and love VPLEX are quivering with excitement at this point.  In a Metro environment VPLEX enables instant vMotion of VMs between sites.  VPLEX makes sure all the data for the VMs are read/write accessible at both locations and VMware auto-magically knows that it can just move the VM running state and BAM! Instant vMotion.  So can VPLEX now do the same thing with LD vMotion and VPLEX Geo (or VPLEX Metro)?  Sadly, no.  But don’t worry, since no one else can do it either!

 

With LD vMotion, VMware has allowed for two separate methods for enabling the vMotion.  The first uses a new file-based version of storage vMotion that runs within ESXi between vSphere clusters.  This system transfers all the base information about the VM, then all the storage of the VM, and finally the running state of the VM between sites.  The long pole here is the transfer of the storage, which is what VPLEX eliminates in a Metro environment.

 

The second mechanism is for VVOL-enabled Active/Active storage.  This means that if a storage array supports VVOLs, and that array also supports Active/Active storage, then the LD vMotion doesn’t have to move the VM storage.  Amazing!  So amazing in fact, as of today, no vendor or product supports this VVOL based mechanism!  So your ONLY choice today is through the vSphere mechanism, and a full storage vMotion.  Feel free to check the VMware support matrix and see for yourself.

 

What does LD vMotion mean for VPLEX customers?  If you are truly transferring VMs at long distance, you have no choice but to sit and wait for your VM storage to transfer, just like everyone else.  If you are actually at sync distances, using VPLEX Metro to pre-stage VM data enables instant vMotion.  And in the not-to-distant future, VMware could (in theory) allow for other VVOL-enabled replication technologies like RecoverPoint and SRDF to pre-stage your VM data over long distances enabling virtually instantaneous LD vMotion.  Pun intended.

 

Like I said before, not much really changes with vSphere 6 and VPLEX.  VVOL support is baking, FT is local only, and LD vMotion support is so limited that your only option is the VMware solution.  For VPLEX the focus continues to be on the benefits gained by using VPLEX Local or VPLEX Metro with your vSphere environment.  Those of you who have VPLEX today know the enormous value of having native VMware HA and VPLEX Continuous Availability protection.  For those of you who don’t…  Isn’t there someone you can talk to about that? I know, stupid question.

 

Cody Garvin

VPLEX Product Manager