Many network engineers recall the iOS7 update on September 18, 2013 as one of the most historic download days of their network’s history. All the more reason for us in the wireless world who anxiously anticipated the September 17 release of iOS8.
We asked a few of our customers to monitor the effect of the software release on their networks and the results for the first two days are in. Those in the education and healthcare space in particular are filled with early adopters of WiFi technology and devices, and eager to get their hands on the latest updates.
Joe Rogers, Associate Network Director at the University of South Florida shared this picture with us from 1pm September 17th, showing 1 Gbps more traffic than he would normally see at this time of day:
Another customer, Greg Sawyer, Manager of Infrastructure Services, shared this picture of the iOS8 effect on his network at the UNSW Australia.
He noted that his experience handling the release this year felt smoother than last year, despite the new peak internet download of 4.65 Gbps and 21Tb downloaded for the day! Not too surprising when considering that there were 27,000 concurrent connections on the wireless network and approximately 60% of those being Apple devices.
How should organizations be considering and handling these network spikes? I sat down with Cisco technical leaders Matt MacPherson and Chris Spain (@Spain_Chris) to get some insight on the effect of big updates like iOS8 on the wireless network. Here are some of the highlights of what we discussed:
The World We Live In
The truth is, more and more services are being moved to the cloud—a cloud that will push updates to millions & in the future billions of users and devices on our networks. Read More »
Tags: #80211ac, 11ac, 8.0, 802.11, 802.11ac, 802.11n, aireOS, Akamai, Android, App, Apple, application, bandwidth, best practice, Burst, business-critical, byod, byte, cache, Cisco, cloud, control, design, device, engineer, fix, Gbps, guide, infrastructure, internet, IOS, ios8, iphone, iphone 6, iphone6, IT admin, IT administration, itunes, mbps, mixpanel, mobile, mobility, network, operation system, OS, patch, peak, pervasive, policy, protocol, protocol pack 11, release, secure, security, services, signal, TB, technology, throughput, unsw, update, USF, visibility, WAN, wi-fi, wide area network, wifi, wireless
Welcome back as we continue to dive deeper into advanced CPU (Central Processing Unit -- I had a “tech writer” change a document on me one time, he assumed at this day in age that people still needed to have the CPU acronym translated.. but I digress) and Memory concepts in the land of VDI. Last week Doron answered our first question and told us about Core Count vs. Core Speed for scalable VDI. This week we will focus specifically on Core Speed, bursting and introduce you to a potentially new subject called “SPEC Blend/Core” for high performance VDI. If you are just finding this blog post for the first time, I encourage you to check out the Introduction from Tony as it will help set the stage for our discussion. Here is the full table of contents:
- Introduction – VDI – The Questions you didn’t ask (but really should)
- VDI “The Missing Questions” #1: Core Count vs. Core Speed
- VDI “The Missing Questions” #2: Core Speed Scaling (Burst) YOU ARE HERE!
- VDI “The Missing Questions” #3: Realistic Virtual Desktop Limits
- VDI “The Missing Questions” #4: How much SPECint is enough
- VDI “The Missing Questions” #5: How does 1vCPU scale compared to 2vCPU’s?
- VDI “The Missing Questions” #6: What do you really gain from a 2vCPU virtual desktop?
- VDI “The Missing Questions” #7: How memory bus speed affects scale
- VDI “The Missing Questions” #8: How does memory density affect VDI scalability?
- VDI “The Missing Questions” #9: How many storage IOPs?
You are Invited! If you’ve been enjoying our blog series, please join us for a free webinar discussing the VDI Missing Questions, with Tony, Doron, Shawn and Jason! Access the webinar here!
VM’s are only as fast as their individual cores! Lets look at what this statement means. Example: Assume we have a 1GHz x 4 core processor (hey, it makes math easy for me). When we carve up a server VM or in this case a VM to be used for VDI, we can’t just give it 2 vCPU’s and say it’s got a 2GHz processor. The reality is that it has a dual 1GHz processor. This becomes an important concept in VDI when you are considering the quantity and QUALITY of vCPU’s you allocate to a Virtual Machine and ultimately the end user applications efficiency and the overall scalability of the server platform. This is not a Uni-processor vs. Multi-processor application discussion. We could easily have a very long discussion and debate on the in’s and out’s of application level efficiencies and the Operating Systems ability (and sometimes inability) to properly manage multiple CPU’s. We are going to expand upon the two CPU’s we tested and dig into per core performance.
CPU Burst vs. CPU Reservation. Let’s play around with our example 1GHz x 4 Core Processor a bit more. If we take this single processor and deploy 8 single vCPU desktops on it we will have a 500MHz CPU reservation per VM. The calculation for that is simple 1GHz x 4 Cores = 4,000MHz / 8 total VM’s = 500MHz/VM Reservation. So the Reservation is simply the average amount of CPU that is available to each VM (assuming everything is prioritized equally). But our Burst is different. Our Burst represents the maximum amount of CPU Core that any one VM could ever utilize. In this example, the Burst per VM is equivalent to 1GHz.
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Tags: Burst, Cisco, desktop virtualization, performances, Speed, vdi
Today I want to bring up DCI use case that I’ve been thinking about: capacity expansion. As you know, the purpose of DCI is to connect two or more Data Centers together so that they share resources and deliver services. The capacity expansion use case is when you have temporary traffic bursts, cloud bursts, either planned or unplanned, maintenance windows, migrations or really any temporary service event that requires additional service capacity.
To start addressing the challenge of meeting these planned and unplanned cloud burst and capacity expansion requirements, check out the new ACE + OTV feature called Dynamic Workload Scaling announced recently.
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Tags: ACE, Burst, Capacity Expansion, Cisco, cloud, Cloud Burst, data center, Data Center Interconnect, DC, DCI, DWS, Dynamic Workload Scaling, locality, Nexus 7000, OTV, SASU, Systems Architecture and Strategy Unit, virtual machine, VM, VM Locality