Year: 2016

AWS direct connect – Connectivity matters!

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I had some discussion about AWS (Amazon Web Services) and how to connect to their services, especifically when you run production workloads on virtual machines in AWS. Bringing workloads to public clouds, means that your business and/or your customers are more depended on their (internet) connectivity to be able to reach the workloads running on public cloud environment.

Connectivity matters

There are a multiple solutions out there to make your internet facing connections highly available. Bandwidth-wise there aren’t really any challenges, aside from the costs… in the Netherlands at least. It is easy to get a 1GbE or better connection from your datacenter or office location(s).

The thing we were discussing about, is the latency between you and your public cloud services. Even though it’s strongly depending on what workloads you are planning to run in AWS, you want a decent user experience. Thus a lowest possible network latency towards that workload. That brings us to www.cloudping.info. A nifty web tool to give you an idea on what your latency is to the regions from where AWS offers their services. It’s output looks like this:

awscloudping

Since I’m in the Netherlands, the EU Frankfurt site in Germany is the closest AWS site for me. So an average ping time of 23ms… Note: This number is depending strongly on how your internet provider or your datacenter is connected to AWS via peering on various Internet Exchanges or via transits.

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Lab test: vSphere Fault Tolerance performance impact

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Triggered by some feedback on the VMware reddit channel, I was wondering what is holding us back in adopting the vSphere Fault Tolerance (FT) feature. Comments on Reddit stated that although the increased availability is desirable, the performance impact is holding them back to actually use it in production environments.

Use cases for FT could be, according to the vSphere 6 documentation center:

  • Applications that need to be available at all times, especially those that have long-lasting client connections that users want to maintain during hardware failure.
  • Custom applications that have no other way of doing clustering or other forms of application resiliency.
  • Cases where high availability might be provided through custom clustering solutions, which are too complicated to configure and maintain.

However, the stated use cases only focus on availability and do not seem to incorporate a performance impact when enabling FT. Is there a sweet-spot for applications that do need high resiliency, but do not require immense performance and could coop with a latency impact due to FT? It really depends on the application workload. A SQL server typically generates more FT traffic then for instance a webserver that primarily transmits. So the impact of enabling FT will impact some workloads more then other.

Requirements

Since the introduction of vSphere 6: Multi-Processor Fault Tolerance (SMP-FT), the requirements for FT are a bit more flexible. The compute maximums for a FT enabled VM are 4 vCPUs and 64GB memory. The use of eager zero thick disks is no longer a requirement. So thin, lazy zeroed thick and eager zero thick provisioned disks are all supported in SMP-FT!
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Our VMworld 2016 session (#8430)

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Oh how do I look forward to VMworld 2016!! Once more I’m able to visit both VMworld US in Las Vegas and VMworld EMEA in Barcelona. This year it’s not all about listening and peering though as I am presenting together with the one and only Frank Denneman!

Next to the fact that presenting at VMworld will be an awesome experience, it’ll also be good to already convey some thoughts & content from our upcoming book in our VMworld session!!

vmworldvegas

Our VMworld session

It is difficult to get a VMworld session accepted. If I remember correctly, there were 1550+ abstracts submitted and only 611 made it into the catalog.  Setting up a good abstract is critical, so I figured it might help to share our submitted abstract. Still, I’m pretty sure even very good abstracts/sessions were rejected which is a shame. I sincerely hope we still get to see this content at your local VMUG or in a vBrownBag TechTalk at VMworld US or EMEA.

Our submitted abstract:
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Top vBlog & VMworld session voting

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It is that time of the year again! The annual top vBlog 2016 voting is open to show your appreciation for all the virtualization bloggers out there. I hope we at Cloudfix have created enough useful and diverse content in order to earn your vote. We sure love what we do, and we will strive to have another successful year of writing interesting blogs.

So click here to start your voting survey which will only takes a few moments. A big shout-out goes out to vSphere-land.com / Eric Siebert and sponsor VMturbo for making it all happen!

If you are willing to vote for us, we are listed in the main voting on the left side (blogs are listed in alphabetical order) and in the independent blogger section.

votevblog2016

In other news, the content catalog for the upcoming VMworld 2016 in Las Vegas is live! Make sure to check it out here! While doing so, it is also possible to cast your vote for your favorite sessions.

Our session (I will be speaking alongside Frank Denneman) is included in the catalog:

votesession2016

 

Thank you in advance for considering us!!

 

 

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Jumbo frames and the risks involved

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Even though the jumbo frame and the possible gain and risk trade-offs discussion is not new, we found ourselves discussing it yet again. Because we had different opinions, it seems like a good idea to elaborate on this topic.

Let’s have a quick recap on what jumbo frames actually are. Your default MTU (Maximum Transmission Unit) for a ethernet frame is 1500. A MTU of 9000 is referred to as a jumbo frame.

Jumbo frames or 9000-byte payload frames have the potential to reduce overheads and CPU cycles.

Typically, jumbo frames are considered for IP storage networks or vMotion networks. A lot of performance benchmarking is already described on the web. It is funny to see a variety of opinions whether to adopt jumbo frames or not. Check this blogpost and this blogpost on jumbo frames performance compared to a standard MTU size. The discussion if ‘jumbo frames provide a significant performance advantage’ is still up in the air.

There are other techniques to improve network throughput and lower CPU utilization next to jumbo frames. A modern NIC will support the Large Segment Offload (LSO) and Large Receive Offload (LRO) offloading mechanisms. Note: LSO is also referenced as TSO (TCP Segmentation Offload). Both are configurable. LSO/TSO is enabled by default if the used NIC hardware supports it. LRO is enabled by default when using VMXNET virtual machine adapters.

Risks?

Let’s put the performance aspects aside, and let us look into the possible risks involved when implementing jumbo frames. The thing is, in order to be effective, jumbo frames must be enabled end to end in the network path. The main risk when adopting jumbo frames, is that if one component in the network path is not properly configured for jumbo frames, a MTU mismatch occurs.
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Stretched cluster with NSX

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Last NLVMUG I was talking about stretched clusters. My presentation elaborated somewhat on how VMware NSX can help you deal with challenges that arise when deploying a stretched cluster solution. In this blogpost I want to have a closer look at this specific topic.

A quick understanding about what a stretched cluster solution actually is; it is a vSphere cluster configured in one vCenter instance containing an equal number of hosts from both sites. This allows for disaster avoidance (vMotion) and disaster recovery (vSphere HA) between two geographical separated sites. From the backend infrastructure perspective, your (synchronous replicated) storage and network solutions must span both sites.

Looking into network designs used for stretched clusters, you will typically face challenges like:

  • How do you design for VM mobility over 2 sites, requiring Layer-2 networks between the 2 sites?
  • Stretched Layer-2 networks (VLANs) introduce a higher risk of failure (think Layer-2 loops).
  • How to properly segment applications and/or tenants (customers/business units)?
  • Netwerk flows. What about your egress and ingress connections?

Let’s begin with how a VMware NSX install-base could look like if it is deployed within stretched cluster infrastructure.

Stretched cluster with NSX architecture

A stretched cluster with VMware NSX could look like the following logical overview.
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