Yellow Bricks

by Duncan Epping

5.5

Virtual SAN (related) PEX Updates

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I am at VMware Partner Exchange this week and there and figured I would share some of the Virtual SAN related updates.

  • 6th of March their is an online Virtual SAN event with Pat Gelsinger, Ben Fathi and John Gilmartin… Make sure to register for it!
  • Ben Fathi (VMware CTO) stated that VSAN will be GA in Q1, more news in the upcoming weeks
  • Maximum cluster size has been increased from 8 (beta) to 16 according to Ben Fathi, VMware VSAN engineering team is ahead of schedule!
  • VSAN has linear scalability, close to a million IOPS with 16 hosts in a cluster (100% read, 4K blocks). Mixed IOPS close to half a million. All of this with less than 10% CPU/Memory overhead. That is impressive if you ask me. Yeah yeah I know, numbers like these are just a part of the overall story… still it is nice to see that this kind of performance numbers can be achieved with VSAN.
  • I noticed a tweet Chetan Venkatesh and it looks like Atlantis ILIO USX (in memory storage solution) has been tested on top of VSAN and they were capable of hitting 120K IOPS using 3 hosts, WOW. There is a white paper on this topic to be found here, interesting read.
  • It was also reinstated that customers who sign up and download the beta will get a 20% discount on the first purchase of 10 VSAN licenses or more!
  • Several hardware vendors announced support for VSAN, a nice short summary by Alberto to be found here.

vSphere HA and VMs per Datastore limit!

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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!

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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

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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

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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…] about Building a hyper-converged platform using VMware technology part 2