Operational simplicity through Flash

A couple of weeks back I had to honor to be one of the panel members at the opening of the Pure Storage office in the Benelux. The topic of course was flash, and the primary discussion around the benefits. The next day I tweeted a quote of one of the answers I gave during the session which was picked up by Frank Denneman in one of his articles, this is the quote:

David Owen responded to my tweet saying that many performance acceleration platforms introduce an additional layer of complexity, and Frank followed up on that in his article. However this is not what my quote was referring to. First of all, I don’t agree with David that many performance acceleration solutions increase operational complexity. However, I do agree that they don’t always make life a whole lot easier either.

I guess it is fair to say that performance acceleration solutions (hyper-visor based SSD caching) are not designed to replace your storage architecture or to simplify it. They are designed to enhance it, to boost the performance. During the Pure Storage panel sessions I was talking about how flash changed the world of storage, or better said is changing the world of storage. When you purchased a storage array in the two decades it would come with days worth of consultancy. Two days typically being the minimum and in some cases a week or even more. (Depending on the size, and the different functionality used etc.) And that was just the install / configure part. It also required the administrators to be trained, in some cases (not uncommon) multiple five-day courses. This says something about the complexity of these systems.

The complexity however was not introduced by storage vendors just because they wanted to sell extra consultancy hours. It was simply the result of how the systems were architected. This by itself being the result of a major big constraint: magnetic disks. But the world is changing, primarily because a new type of storage was introduced; Flash!

Flash allowed storage companies to re-think their architecture, probably fair to state that the this was kickstarted by the startups out there who took flash and saw this as their opportunity to innovate. Innovationg by removing complixity. Removing (front-end) complexity by flattening their architecture.

Complex constructs to improve performance are no longer required as (depending on which type you use) a single flash disk delivers more than a 1000 magnetic disks typically do. Even when it comes to resiliency, most new storage systems introduced different types of solutions to mitigate (disk) failures. No longer is a 5-day training course required to manage your storage systems. No longer do you need weeks of consultancy just to install/configure your storage environment. In essence, flash removed a lot of the burden that was placed on customers. That is the huge benefit of flash, and that is what I was referring to with my tweet.

One thing left to say: Go Flash!

vSphere HA and VMs per Datastore limit!

I felt I would need to get this out there, as it is not something many seem to be aware off . More and more people are starting to use storage solutions which offer 1 large shared datastore, examples are solutions like Virtual SAN, Tintri and Nutanix. I have seen various folks saying: unlimited number of VMs per datastore, but of course there are limits to everything! If you are planning to build a big cluster (HA enabled), keep in mind that per cluster your limit for a datastore is 2048 powered-on virtual machines! Say what? Yes that is right, per cluster you are limited to 2048 powered-on VMs on a single datastore. This is documented in the Max Config Guide of both vSphere 5.5 and vSphere 5.1. Please note it says datastore and not VMFS or NFS explicitly, this applies to both!

The reason for this today is the vSphere HA poweron list. I described that list in this article, in short: this list keeps track of the power-state of your virtual machines If you need more VMs in your cluster than 2048 you will need to create multiple datastores for now. (More details in the blog post) Do note that this is a known limitation and I have been told that the engineering team is researching a solution to this problem. Hopefully it will be in one of the upcoming releases.

Virtual SAN Compatibility Guide updated!

For those looking to start configuring hardware for VSAN / Virtual SAN infrastructures, the VMware Compatibility Guide just got updated!

Personally I find the new section on disk controllers very useful as it shows whether the controller is supported in SAS / SATA / RAID-0 or Pass-through. I can’t wait for the first VSAN Ready Nodes to pop-up. Note that VSAN is not GA yet, so I expect the HCL to be expanded even further over time. Just like to say: Nice work Dell, it looks you folks are really making an effort getting your hardware certified.

Awesome VSAN contest results

Every once in a while I have someone asking me how about VSAN scale? Typically the question is triggered by a conversation had with another storage vendor and either a misunderstanding or pure FUD that was spread. It is nice to see some of our beta testers showing the possibilities with VSAN. How about the result of the Miami VMUG? These guys managed to get their hands on 3 awesome Dell R720xd hosts and found someone willing to host them. Then they started building, and it didn’t take them long to figure out what the limit was on a 3 node cluster… They managed to run 2250 virtual machines on 3 hosts. Yes, that is indeed more than two thousand virtual machines.

Thanks Miami VMUG for going all out.

Building a hyper-converged platform using VMware technology part 2

In part 1 of “Building a hyper-converged platform using VMware technology” I went through the sizing and scaling exercise. In short to recap, in order to run 100 VMs we would need the following resources:

  • 100 x 1.5 vCPUs = ~30 cores
  • 100 x 5 GB = 500GB of memory
  • 100 x 50 GB (plus FTT etc) = 11.8 TB of disk space

From a storage perspective 11.8 TB is not a huge amount, 500 GB of memory can easily fit in a single host today, and 30 cores… well maybe not easilyin a single host but it is no huge requirement either. What are our options? Lets give an example of some server models that fall into the category we are discussing:

  • SuperMicro Twin Pro – 2U chassis with 4 nodes. Per node: Capable of handling 6 * 2.5″ drives and on-board 10GbE. Supports the Intel E-2600 family and up to 1TB of memory
    • SuperMicro is often used by startups, especially in the hyperconverged space but also hybrid storage vendors like Tintri use their hardware. Hey SuperMicro Marketing Team, this is something to be proud of… SuperMicro powers more infrastructure startups than anyone else probably!
    • Note you can select 3 different disk controller types, LSI 3108, LSI 3008 and the Intel C600. Highly recommend the LSI controllers!
  • HP Sl2500t – 2U chassis with 4 nodes. Per node: Capable of handling 6 * 2.5″ or 3 * 3.5″ drives and FlexibleLOM 10GbE can be included. Supports the Intel E-2600 family and up to 512GB of memory
    • You can select from the various disk controllers HP offers, do note that today there are a limited number of controllers certified.
    • Many probably don’t care, but the HP kit just looks awesome :)
  • Dell C6000 series – 2U chassis with 4 nodes. Per node: Capable of handling 6 * 2.5″ per node or 3 * 3.5″ drives. Supports the Intel E-2600 family and up to 512GB of memory
    • Note there is no on-board 10GbE or “LOM” type of solution, you will need to add a 10GbE PCIe card.
    • Dell offers 3 different disk controllers including the LSI 2008 series. Make sure to check the HC.

First thing to note here is that all of the configuration above by default come with 4 nodes, yes you can order them with less but personally I wouldn’t recommend that. Strange thing is that in order to get configuration details for the Dell and HP you need to phone them up, so lets take a look at the SuperMicro Twin Pro as there are details to be found online. What are our configuration options? Well plenty I can tell you that. CPUs ranging low-end Quad-core 1.8GHz up to Twelve-core 2.7 GHz Intel CPUs. Memory configurations ranging from 2GB DIMMS to 32GB DIMMS including the various speeds. Physical disks ranging from 250GB 7200 RPM SATA Seagate to 1.2TB 10k RPM SAS Hitachi drives. Unlimited possibilities, and that is probably where it tends to get more complicated. [Read more…]