A bit of a controversial title, no?
Allow me to elaborate.
EMC posted a new SPEC SFS result as part of a marketing stunt (which is working, look at what I’m doing – I’m talking about them, if only to clear the air).
In simple terms, EMC got almost 500,000 SPEC SFS NFS IOPS (not to be confused with, say, block-based SPC-1 IOPS) with the following configuration:
- Four (4) totally separate VNX arrays, each loaded with SSD storage, utterly unaware of each other (8 total controllers since each box has 2)
- Five (5) Celerra VG8 NAS heads/gateways (1 spare), one on top of each VNX box
- 2 Control Stations
- 8 exported filesystems (2 per VG8 head/VNX system)
- Multiple pools of storage (at least 1 per VG8) – not shared among the various boxes, no data mobility between boxes
- Only 60TB NAS space with RAID5 (or 15TB per box)
Now, this post is not about whether this configuration is unrealistic and expensive (almost nobody would pay $6m for merely 60TB of NAS, not today). I get it that EMC is trying to publish the best possible number by loading a bunch of separate arrays with SSD. It’s OK as long as everyone understands the details.
My beef has to do with how it’s marketed.
EMC is very vague about the configuration, unless you look at the actual SPEC website. In the marketing materials they just mention VNX, as in “The EMC VNX performed at 497,623 SPECsfs2008_nfs.v3 operations per second”. Kinda like saying it’s OK to take 3 5-year olds and a 6-year old to a bar because their age adds up to 21.
No – the far more accurate statement is “four separate VNXs working independently and utterly unaware of each other did 124,405 SPEC fs2008_nfs.v3 operations per second each“.
All EMC did was add up the result of 4 boxes.
Heck, that’s easy to do!
NetApp already has a result for the 6240 (just 2 controllers doing a respectable 190,675 SPEC NFS ops taking care of NAS and RAID all at once since they’re actually unified, no cornucopia of boxes there) without using Solid State Drives (common SAS drives plus a large cache were used instead – a standard, realistic config we sell every day, and not a “lab queen”).
If all we’re doing is adding up the result of different boxes, simply multiply this by 4 (plus we do have Cluster-Mode for NAS so it would count as a single clustered system with failover etc. among the nodes) and end up with the following result:
- 762,700 SPEC SFS NFS operations
- 8 exported filesystems
- 343TB usable with RAID-DP (thousands of times more resilient than RAID5)
So, which one do you think is the better deal? More speed, 343TB and better protection, or less speed, 60TB and far less protection?
Customers curious about other systems can do the same multiplication trick for other configs, the sky is the limit!
The other, more serious part, and what prompted me to title the post the way I did, is that EMC’s benchmarking made pretty clear the fact that the VNX is the bottleneck, only able to really support a single VG8 head at top speed, necessitating the need for 4 separate VNX systems to accomplish the final result. So, the fact that a VNX can have up to 8 Celerra heads on top of it means nothing since the back-end is your limiting factor. You might as well stick to a dual-head VG8 config (1 active 1 passive) since that’s all it can comfortably drive (otherwise why benchmark it that way?)
But with only 1 active NAS head you’d be limited to just 256TB max NAS capacity, since that’s how much total space a Celerra head can address as of the time of this writing. Which is probably enough for most people.
I wonder if the NAS heads that can be bought as a package with VNX are slower than VG8 heads, and by how much. You see, most people buying the VNX will be getting the NAS heads that can be packaged with it since it’s cheaper that way. How fast does that go? I’m sure customers would like to know, since that’s what they will typically buy.
I also wonder how fast it would be with RAID6.
Here’s a novel idea: benchmark what customers will actually buy!
So apples-to-apples comparisons can become easier instead of something like this:
For the curious: on the left you see an “Autumn Glory” Malus Floribunda (miniature apple). Photo courtesy of John Fullbright.