NVM Express over Fabrics


Any technologist who’s read, let alone used NVM Express (NVMe), is pretty enthusiastic about it’s capabilities and if it was not for availability and financial restrictions we’d all have at least a couple in our home systems and labs. It seems to succeed very well in making sure the host can keep up with the performance (low latencies, high throughput)) delivered by SSD drives than our current interfaces.

This means that many are very happy with future visions on how PCIe will dislodge SAS/SATA as the preferred SSD interface. This might seem feasible for local storage right now but how to deal with this in an actual storage array, what if we want to size this to a larger scale? There are no “PCIe JBODS”. So what does one do? Well, how did we do it in the past with FC? We created a fabric. Below we see several local & remote NVMe architectures even hybrid ones with traditional SAS.

image

That’s exactly what NVM Express Inc. is doing, creating the specs for a fabric. This holds the promise to achieve superior results due to the elimination of SCSI translation which reduces latency significantly by delivering NVMe end to end. Not only that but we also see the following efforts in the NVM Express Specification 1.2 to give it enterprise grade capabilities beyond pure performance.

  • Enhanced status reporting
  • Expanded capabilities including live firmware updates

There have been some early demos of NVMe over Fabrics mainly focusing on the “remote” performance. While local NVMe SSDs have the edge on absolute IOPS the difference with NVMe over a fabric is not significant. The reduction in latency is measured in < 10 µs,so that’s good news. The fabric leverages RDMA (yes, yet another reason that my time spending with this technology has been a useful investment). This can be Infiniband, RoCE or iWarp. There’s also the new kid on the block “Intel Omni Scale”  (even if their early demo used iWARP). There’s also a Mellanox RoCE demo.

image

Now with NVMe SSD disk speeds it seems that the writing is on the wall that ever better fabric performance will be needed to support the tremendous throughput this evolution of storage can deliver. RDMA seems poised for success in regards to this. Now, yes, strictly speaking the NVMe traffic does not require RDMA but let’s just say I don’t see anyone building it without. I also think this means even iWarp fabrics will use DCB (PFC) to make sure we have a lossless network. The amount of traffics will be immense and why not optimize for the best possible performance? I hold the opinion this is beneficial for east-west traffic today in larger environments, especially when in converged networks. Unless the Intel® Omni-Path Architecture blows everyone else away that is Smile. Too early to tell.

Now does this dictate the total and absolute obsolescence of iSCSI and FC? No. There is no reason why a NVMe Fabrics storage solution cannot offer storage to hosts via FC, iSCSI, SMB 3, NFS, FCoE, … They, potentially could even offer iWarp, RoCE or Infiniband to the hosts so you won’t lose your prior investments or get locked into one. I have no magic ball so I cannot tell you if this will happen. What I do now that when it comes to MPIO versus multichannel for load balancing and even failover and recovery, multichannel sometimes does a (far?) superior job in my honest opinion especially with older hypervisors even when the hypervisor uses separate sessions per virtual machine to achieve better load balancing over iSCSI or the like. Anyway, I digress. One thing I do know is that I’ll keep a keen eye on what Microsoft is doing in this space, especially in regards to Windows Server 2016. It’s time to up the level on scalability & support for newer technologies once again.

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SMB Direct over RoCE Demo – Hosts & Switches Configuration Example


As mentioned in Where SMB Direct, RoCE, RDMA & DCB fit into the stack this post’s only function is to give you an overview of the configurations used in the demo blogs/videos. First we’ll configure one Windows Server 2012 R2 host. I hope it’s clear this needs to be done on ALL hosts involved. The NICs we’re configuring are the 2 RDMA capable 10GbE NICs we’ll use for CSV traffic, live migration and our simulated backup traffic. These are Mellanox ConnectX-3 RoCE cards we hook up to a DCB capable switch. The commands needed are below and the explanation is in the comments. Do note that the choice of the 2 policies, priorities and minimum bandwidths are for this demo. It will depend on your environment what’s needed.

#Install DCB on the hosts
Install-WindowsFeature Data-Center-Bridging
#Mellanox/Windows RoCE drivers don't support DCBx (yet?), disable it.
Set-NetQosDcbxSetting -Willing $False
#Make sure RDMA is enable on the NIC (should be by default)
Enable-NetAdapterRdma –Name RDMA-NIC1
Enable-NetAdapterRdma –Name RDMA-NIC2
#Start with a clean slate
Remove-NetQosTrafficClass -confirm:$False
Remove-NetQosPolicy -confirm:$False

#Tag the RDMA NIC with the VLAN chosen for PFC network
Set-NetAdapterAdvancedProperty -Name "RDMA-NIC-1" -RegistryKeyword "VlanID" -RegistryValue 110
Set-NetAdapterAdvancedProperty -Name "RDMA-NIC-2" -RegistryKeyword "VlanID" -RegistryValue 120

#SMB Direct traffic to port 445 is tagged with priority 4
New-NetQosPolicy "SMBDIRECT" -netDirectPortMatchCondition 445 -PriorityValue8021Action 4
#Anything else goes into the "default" bucket with priority tag 1 🙂
New-NetQosPolicy "DEFAULT" -default  -PriorityValue8021Action 1

#Enable PFC (lossless) on the priority of the SMB Direct traffic.
Enable-NetQosFlowControl -Priority 4
#Disable PFC on the other traffic (TCP/IP, we don't need that to be lossless)
Disable-NetQosFlowControl 0,1,2,3,5,6,7

#Enable QoS on the RDMA interface
Enable-NetAdapterQos -InterfaceAlias "RDMA-NIC1"
Enable-NetAdapterQos -InterfaceAlias "RDMA-NIC2"

#Set the minimum bandwidth for SMB Direct traffic to 90% (ETS, optional)
#No need to do this for the other priorities as all those not configured
#explicitly goes in to default with the remaining bandwith.
New-NetQoSTrafficClass "SMBDirect" -Priority 4 -Bandwidth 90 -Algorithm ETS

We also show you in general how to setup the switch. Don’t sweat the exact syntax and way of getting it done. It differs between switch vendors and models (we used DELL Force10 S4810 and PowerConnect 8100 / N4000 series switches), it’s all very alike and yet very specific. The important thing is that you see how what you do on the switches maps to what you did on the hosts.

!Disable 802.3x flow control (global pause)- doesn't mix with DCB/PFC
workinghardinit#configure
workinghardinit(conf)#interface range tengigabitethernet 0/0 -47 
workinghardinit(conf-if-range-te-0/0-47)#no flowcontrol rx on tx on
workinghardinit(conf-if-range-te-0/0-47)# exit
workinghardinit(conf)# interface range fortyGigE 0/48 , fortyGigE 0/52
workinghardinit(conf-if-range-fo-0/48-52)#no flowcontrol rx on tx off
workinghardinit(conf-if-range-fo-0/48-52)#exit

!Enable DCB & Configure VLANs
workinghardinit(conf)#service-class dynamic dot1p
workinghardinit(conf)#dcb enable
workinghardinit(conf)#exit
workinghardinit#copy running-config startup-config
workinghardinit#reload

!We use a <> VLAN per subnet
workinghardinit#configure
workinghardinit(conf)#interface vlan 110
workinghardinit (conf-if-vl-vlan-id*)#tagged tengigabitethernet 0/0-47
workinghardinit (conf-if-vl-vlan-id*)#tagged port-channel 3
workinghardinit(conf)#interface vlan 120
workinghardinit (conf-if-vl-vlan-id*)#tagged tengigabitethernet 0/0-47
workinghardinit (conf-if-vl-vlan-id*)#tagged port-channel 3
workinghardinit (conf-if-vl-vlan-id*)#exit


!Create & configure DCB Map Policy
workinghardinit(conf)#dcb-map SMBDIRECT
workinghardinit(conf-dcbmap-profile-name*)#priority-group 0 bandwidth 90 pfc on 
workinghardinit(conf-dcbmap-profile-name*)#priority-group 1 bandwidth 10 pfc off 
workinghardinit(conf-dcbmap-profile-name*)#priority-pgid 1 1 1 1 0 1 1 1
workinghardinit(conf-dcb-profile-name*)#exit 

!Apply DCB map to the switch ports & uplinks
workinghardinit(conf)#interface range ten 0/047
workinghardinit(conf-if-range-te-0/0-47)# dcb-map SMBDIRECT 
workinghardinit(conf-if-range-te-0/0-47)#exit
workinghardinit(conf)#interface range fortyGigE 0/48 , fortyGigE 0/52
workinghardinit(conf-if-range-fo-0/48,fo-0/52)# dcb-map SMBDIRECT
workinghardinit(conf-if-range-fo-0/48,fo-0/52)#exit
workinghardinit(conf)#exit
workinghardinit#copy running-config startup-config 

With the hosts and the switches configured we’re ready for the demos in the next two blog posts. We’ll show Priority Flow Control (PFC) and Enhanced Transmission Selection (ETS) in action with some tips on how to test this yourselves.

SMB Direct with DCB, PFC, ETS … How do I know it works?!


A question that comes up over time, again and again, is how do you know SMB Direct is working. The question stems from a nagging feeling that configuring DCB is a bit of playing wizard’s apprentice and we might not completely know what we’re doing, i.e. lack of experience.

image

Many have suspected me of brewing up DCB configurations in a dark corner of the data center where no one else dares venture. But those are unsubstantiated rumors. But in coming blog posts we’ll address how to configure it end to end and we’ll show how to find out if it’s really working and how to test that.

Finding out if it really works, testing and monitoring isn’t magic. It boils down to using tools you know. Performance counters for RDMA Activity and SMB direct are natively available in Windows. Use them!The NIC vendors also provide very detailed counters, those are excellent and of great value when testing and confirming things work as they should. The latter is very important. Because after people are satisfied SMB Direct works they want to know if DCB is configured correctly. Does PFC work, are pause frames being send and received? Is it really lossless?  Does ETS really kick in when needed, do I get the minimum bandwidth I configured? These are very valid questions people struggle with. But the answer eludes many, almost like the question if the refrigerator light really goes out when you close the door.

It’s hard to do deep down in the network packets … that often requires a very specialized skillset and experience with packet analyzers etc. Nothing most of you can’t learn but often this is not a priority. But with some creativity and the performance counters on windows provided by the NIC vendors and the statistics counters on the switches you can demonstrate that both PFC & ETS doe work and kick in.

So in upcoming blogs & videos I’ll demonstrate the configuring SMB Direct over RoCE leveraging 2 parts of DCB:

  • PFC (Priority Flow Control) – mandatory for SMB Direct over RoCE
  • ETS (Enhanced Transmission Selection) – optional but I advise you to leveraged it for SMB Direct over RoCE

Actually, when doing true converged, no matter what route you go, QoS is not really optional any more.

The biggest challenge is to get people to wrap their heads around the concepts and it’s behavior. Once you do that you’ll understand how and why to configure it. It took me time and effort, there’s no way around it, but it’s well worth the effort.

Look, DCB is not 100% fully matured or perfect especially in large scale environments over > 2 or 3 hops. Frak, while I love tinkering, testing and playing with this stuff I have never been a “QoS first person”. If I can I thrown resources at the problem (CPU cycles; memory, bandwidth, …). QoS is like a gun. You only draw it when you must use it and than you’d better do it right otherwise you don’t touch it, bar for practice/training/ education. While perfection is not of this world and improvements are being worked on (ECN) it does work and deliver. How many of you had a large scale > 2 hops , > 20 switches deployment with FC, FCoE or iSCSI to worry about? So can it deliver what you need today in most scenarios? Yes! Can I fix the short comings of any random technologies? No. Can I leverage current technologies with great success despite this? Yes! So can you. There is a reason I get hired and paid. Trust me it’s not my looks, my bed side manner or charismatic appearance Winking smile.

Side note 1: I’m cannot possibly provide a switch configuration guide in a step by step fashion as the details vary by vendor, they can also be switch model/type specific and it all depends on your environment & needs. So no I cannot and will not attempt to write a bunch of these. This would be way too much work and way too expensive (time, hardware etc.), so unless I’m paid very generously to do so, you’re out of luck. It might be cheaper to hire me or to come to the free community sessions, presentations, ATE evenings and study up.

SMB Direct With RoCE in a Mixed Switches Environment


I’ve been setting up a number of Hyper-V clusters with  Mellanox ConnectX3 Pro dual port 10Gbps Ethernet cards. These Mellanox cards provide a nice amount of queues (128) for DVMQ and also give us RDMA/SMB Direct capabilities for CSV & live migration traffic.

Mixed Switches Environments

Now RoCE and DCB is a learning curve for all of us and not for the faint of heart. DCB configuration is non trivial, certainly not across multiple hops and different switches. Some say it’s to be avoided or can’t be done.

You can only get away with a single pair of (uniform) switches in smaller deployments. On top of that I’m seeing more and more different types of switches being used to optimize value, so it’s not just a lab exercise to do this. Combine this with the fact that DCB is an unavoidable technology in networking, unless it get’s replaced with something better and easier, and you might as well try and learn. So I did.

Well right now I’m successfully seeing RoCE traffic going across cluster nodes spread over different racks in different rows at excellent speeds. The core switches are DELL Force10 S4810 and the rack switches are PowerConnect 8132Fs. By borrowing an approach from spine/leave designs this setup delivers bandwidth where they need it a a price point they can afford. They don’t need more expensive switches for the rack or the core as these do support DCB and give the port count needed at the best price point.  This isn’t supposed to be the top in non blocking network design. Nope but what’s available & affordable today in you hands is better than perfection tomorrow. On top of that this is a functional learning experience for all involved.

We see some pause frames being sent once in a while and this doesn’t impact speed that very much. It does guarantee lossless traffic which is what we need for RoCE. When we live migrate 300GB worth of memory across the nodes in the different racks we get great results. It varies a bit depending on the load the switches & switch ports are under but that’s to be expected.

Now tests have shown us that we can live migrate just as fast with non RDMA 10Gbps as we can with RDMA leveraging “only” Multichannel. So why even bother? The name of the game low latency and preserving CPU cycles for SQL Server or storage traffic over SMB3. Why? We can just buy more CPUs/Cores. Great, easy & fast right? But then with SQL licensing comes into play and it becomes very expensive. Also storage scenarios under heavy load are not where you want to drop packets.

Will this matter in your environment? Great question! It depends on your environment. Sometimes RDMA is needed/warranted, sometimes it isn’t. But the Mellanox cards are price competitive and why not test and learn right? That’s time well spent and prepares you for the future.

But what if it goes wrong … ah well if the nodes fail to connect over RDAM you still have Multichannel and if the DCB stuff turns out not to be what you need or can handle, turn it of and you’ll be good.

RoCE stuff to test: Routing

Some claim it can’t be done reliably. But hey they said that for non uniform switch environments too Winking smile. So will it all fall apart and will we need to standardize on iWarp in the future?  Maybe, but isn’t DCB the technology used for lossless, high performance environments (FCoE but also iSCSI) so why would not iWarp not need it. Sure it works without it quite well. So does iSCSI right, up to a point? I see these comments a lot more form virtualization admins that have a hard time doing DCB (I’m one so I do sympathize) than I see it from hard core network engineers. As I have RoCE cards and they have become routable now with the latest firmware and drivers I’d love to try and see if I can make RoCE v2 or Routable RoCE work over different types of switches but unless some one is going to sponsor the hardware I can’t even start doing that. Anyway, lossless is the name of the game whether it’s iWarp or RoCE. Who know what we’ll be doing in 5 years? 100Gbps iWarp & iSCSI both covered by DCB vNext while FC, FCoE, Infiniband & RoCE have fallen into oblivion? We’ll see.

SMB Direct: Choosing A Flavor


I often get asked what to buy for implementing SMB Direct. It’s a non trivial question actually and I’m not an expert, nor do I play one on TV.  All joking aside, it’s a classical consulting answer: it depends. I don’t do free consulting in a blog post, even if that was possible, as there are many factors such as the characteristics and futures of your organization. There’s also a lot of FUD & marketing flying around. Basically in real life you only have two vendors: Cheslio (iWarp) and Mellanox (Roce/Infiniband). Hard to say which one is best. You make the best choice for your company and you live with it.

There is talk about other vendors joining the SMB Direct market. But it seems to be taking a while. This is not that strange. I’ve understood that in the early days of this century iWarp got a pretty bad reputation due to the many issues around it. Apparently offloading the TCP/IP stack to the NIC, which is what iWarp does is not an easy endeavor. Intel had some old Net card a couple of years ago but has gotten out of the game. Perhaps they’ll step back in but that might very well take a couple of years.

Other vendors like Broadcom, Emulex & QLogic might be working on solutions but I’m not holding my breath. Broadcom has DCB and has been hinting at RDMA in it’s NICs for many years but as of the writing of this post there is nothing functional out there yet. But bar the slowness (is complexity slowing the process?) it will be very interesting to see what they’ll choose: RoCE or iWarp. That choice might be the most public statement we’ll ever see about what technology seems like the best bet for these companies. But be careful, I have seen technology choices based on working/living with design choices at at another level due to constrictions in hardware & software that are no longer true today. So don’t just do blindly what others do.

Infiniband will remain a bit more of a niche I think and my guess is that RoCE is the big bet of Mellanox for the long term. 10Gbps and higher Ethernet switches are sold to everyone in the world. Infiniband, not so much. Does that make it a bad choice? Nope, it all depends. Just like FC is not a bad choice for everyone today, it depends.

Your options today

The options you have today to do SMB Direct are rather limited and bound to the different flavors and their vendor. Yes vendor not vendors.

  1. iWarp: Chelsio
  2. RoCE: Mellanox (v2 of RoCE has brought routability into the game, which counters one of iWarps biggest advantages, next to operational ease but the no fuss about DCB story might not be 100% correct, the question is if this matters, after all many people do well with iSCSI which is easy but has performance limits).
  3. Infiniband: Mellanox (Qlogic was the only other remaining one, but Intel bought it form them. I have never ever seen Intel Infiniband in the wild.

Note: You can do iWarp (and even RoCE in theory) without DCB but in all realistic high traffic situations you’ll want to implement PFC to keep the experience and results good under load. Especially the ports connecting to the SOFS nodes could other wise potentially drop packets. iWarp, being TCP/IP, will handle dropped packets but possibly at the cost of deteriorated performance. With RoCE you’re basically toast if you lose packets, it should be losses. I’m not too convinced that pure offloaded TCP/IP scales. Let’s face it, what was the big deal about lossless iSCSI => DCB Smile I would really love to see Demartek testing these things out for us.

If you have a smaller environment, no need for routing and minimal politics I have seen companies select Infiniband which per Gbps is very cheap. Lots of people have chosen iWarp due to it simplicity (which they heavily market) and routability. The popularity however has dropped due to prices hikes that came with increased demand and no competition. RoCE  is popular (I see it the most) and affordable but for this one you MUST do at least PFC. DCB support on switches is not an issue, even budget friendly DELL PowerConnect N4000 series supports it as did it’s predecessor the PC8100 series. Meaning if you have bought switches in the past 24 months and did your home work you’re good to go. Are routability and distance important? Well perhaps not that much today but as the trend in networking is heading for layer 3 down to the rack which will be more acceptable when we see a lot of the workload goodness in hypervisors (Live Migration, vMotion,yes there is work being done on that) being lit up in layer 3 it might become a key feature.

I Can’t Afford 10GBps For Hyper-V And Other Lies


You’re wrong

There, I said it. Sure you can. Don’t think you need to be a big data center to make this happen. You just need to think and work outside the box a bit and when you’re not a large enterprise, that’s a bit more easy to do. Don’t do it like a big name brand, traditionalist partner would do it (strip & refit the entire structural cabling in the server room, high end gear with big margins everywhere). You’re going for maximum results & value, not sales margins and bonuses.

I would even say you can’t afford to stay on 1Gbps much longer or you’ll be dealing with the fall out of being stuck in the past. Really some of us are already look at > 10Gbps connections to the servers, actually. You need to move from 1Gbps or you’ll be micro managing a way around issues sucking all the fun out of your work with ever diminishing results and rising costs for both you and the business.

Give your Windows Server 2012R2 Hyper-V environment the bandwidth it needs to shine and make the company some money. If all you want to do is to spent as little money as possible I’m not quite sure what your goal is? Either you need it or you don’t.  I’m convinced we need it. So we must get it. Do what it takes. Let me show you one way to get what you need.

Sounds great what do I do?

Take heart, be brave and of good courage! Combine it with skills, knowledge & experience to deliver a 10Gbps infrastructure as part of ongoing maintenance & projects. I just have to emphasize that some skills are indeed needed, pure guts alone won’t do it.

First of all you need to realize that you do not need to rip and replace your existing network infrastructure. That’s very hard to get approval for, takes too much time and rapidly becomes very expensive in both dollars and efforts. Also, to be honest, quiet often you don’t have that kind of pull. I for one certainly do not. And if I’d try to do that way it takes way too many meetings, diplomacy, politics, ITIL, ITML & Change Approval Board actions to make it happen. This adds to the cost even more, both in time and money. So leave what you have in place, for this exercise we assume it’s working fine but you can’t afford to have wait for many hours while all host drains in 6 node cluster and you need to drain all of them to add memory. So we have a need (OK you’ll need a better business case than this but don’t make to big a deal of it or you’ll draw unwanted attention) and we’ve taking away the fear factor of fork lift replacing the existing network which is a big risk & cost.

So how do I go about it?

Start out as part of regular upgrades, replacement or new deployments. The money is their for those projects. Make sure to add some networking budget and leverage other projects need to support the networking needs.

Get a starter budget for a POC of some sort, it will get your started to acquire some more essential missing  bits.

By reasonably cheap switches of reasonable port count that do all you need. If they’re readily available in a frame work contract, great. You can get it as part of the normal procedures. But if you want to nock another 6% to 8% of the cost order them directly from the vendor. Cut out the middle man.

Buy some gear as part of your normal refresh cycle. Adapt that cycle life time a bit to suit your needs where possible. Funding for operation maintenance & replacement should already be in place right?

Negotiate hard with your vendor. Listen, just like in the storage world, the network world has arrived at a point where they’re not going to be making tons of money just because they are essential. They have lots of competition and it’s only increasing. There are deals to be made and if you chose the right hardware it’s gear that won’t lock you into proprietary cabling, SPF+ modules and such. Or not to much anyway Smile.

Design options and choices

Small but effective

If you’re really on minimal budget just introduce redundant (independent) stand alone 10Gbps switches for the East-West traffic that only runs between the nodes in the data center. CSV, Live Migration, backup. You don’t even need to hook it up to the network for data traffic, you only need to be able to remotely manage it and that’s what they invented Out Off Band (OOB) ports for. See also an old post of mine Introducing 10Gbps With A Dedicated CSV & Live Migration Network (Part 2/4). In the smallest cheapest scenario I use just 2 independent switches. In the other scenario build a 2 node spine and the leaf. In my examples I use DELL network gear. But use whatever works best for your needs and your environment. Just don’t go the “nobody ever got fired for buying XXX” route, that’s fear, not courage! Use cheaper NetGear switches if that fits your needs. Your call, see my  recent blog post on this 10Gbps Cheap & Without Risk In Even The Smallest Environments.

Medium sized excellence

First of all a disclaimer: medium sized isn’t a standardized way of measuring businesses and their IT needs. There will be large differences depending on you neck of the woods Smile.

Build your 10Gbps infrastructure the way you want it and aim it to grow to where it might evolve. Keep it simple and shallow. Go wide where you need to. Use the Spine/Leaf design as a basis, even if what you’re building is smaller than what it’s normally used for. Borrow the concept. All 10Gbps traffic, will be moving within that Spine/Leaf setup. Only client server traffic will be going out side of it and it’s a small part of all traffic. This is how you get VM mobility, great network speeds in the server room avoiding the existing core to become a bandwidth bottleneck.

You might even consider doing Infiniband where the cost/Gbps is very attractive and it will serve you well for a long time. But it can be a hard sell as it’s “another technology”.

Don’t panic, you don’t need to buy a bunch of Nexus 7000’s  or Force10 Z9000 to do this in your moderately sized server room. In medium sized environment I try to follow the “Spine/Leaf” concept even if it’s not true ECMP/CLOSS, it’s the principle. For the spine choose the switches that fit your size, environment & growth. I’ve used the Force10 S4810 with great success and you can negotiate hard on the price. The reasons I went for the higher priced Force10 S4810 are:

  • It’s the spine so I need best performance in that layer so that’s where I spend my money.
  • I wanted VLT, stacking is a big no no here. With VLT I can do firmware upgrades without down time.
  • It scales out reasonably by leveraging eVLT if ever needed.

For the ToR switches I normally go with PowerConnect 81XX F series or the N40XXF series, which is the current model. These provide great value for money and I can negotiate hard on price here while still getting 10Gbps with the features I need. I don’t need VLT as we do switch independent NIC teaming with Windows. That gives me the best scalability wit DVMQ & vRSS and allows for firmware upgrades without any network down time in the rack. I do sacrifice true redundant LACP within the rack but for the few times I might really need to have that I could go cross racks & still maintain a rack a failure domain as the ToRs are redundant. I avoid stacking, it’s a single point of failure during firmware upgrades and I don’t like that. Sure I can could leverage the rack a domain of failure to work around that but that’s not very practical for ordinary routine maintenance. The N40XXF also give me the DCB capabilities I need for SMB Direct.

Hook it up to the normal core switch of the existing network, for just the client/server.(North/South) traffic. I make sure that any VLANs used for CSV, live migration, can’t even reach that part of the network.  Even data traffic (between virtual machines, physical servers) goes East-West within your Spine/Leave and never goes out anyway unless you did something really weird and bad.

As said, you can scale out VLT using eVLT that creates a port channel between 2 VLT domains. That’s nice. So in a medium sized business you’re pretty save in growth. If you grow beyond this, we’ll be talking about a way larger deployment anyway and true ECMP/CLOS and that’s not the scale I’m dealing with where. For most medium sized business or small ones with bigger needs this will do the job. ECMP/CLOS Spine/leaf actually requires layer 3 in the design and as you might have noticed I kind if avoid that. Again, to get to a good solution today instead of a real good solution next year which won’t happen because real good is risky and expensive. Words they don’t like to hear above your pay grade.

The picture below is just for illustration of the concept. Basically I normally have only one VLT domain and have two 10Gbps switches per rack. This gives me racks as failure domains and it allows me to forgo a lot of extra structural cabling work to neatly provide connectivity form the switches  to the server racks .image

You have a  scalable, capable & affordable 10Gbps or better infrastructure that will run any workload in style.. After testing you simply start new deployments in the Spine/Leaf and slowly mover over existing workloads. If you do all this as part of upgrades it won’t cause any downtime due to the network being renewed. Just by upgrading or replacing current workloads.

The layer 3 core in the picture above is the uplink to your existing network and you don’t touch that. Just let if run until there nothing left in there and you can clean it up or take it out. Easy transition. The core can be left in place or replaces when needed due to age or capabilities.

To keep things extra affordable

While today the issues with (structural) 10Gbps copper CAT6A and NICs/Switches seem solved, when I started doing 10Gbps fibre cabling of Copper Twinax Direct Attach was the only way to go. 10GBaseT wasn’t an option yet and I still love the flexibility of fibre, it consumes less space and weighs less then CAT6A. Fibre also fits easily in existing cable infrastructure. Less hassle. But CAT6A will work fine today, no worries.

If you decide to do fibre, buy OM3, you can get decent, affordable cabling on line. Order it as consumable supplies.

Spend some time on the internet and find the SFP+ that works with your switches to save a significant amount of money. Yup some vendor switches work with compatible non OEM branded SPF+ modules. Order them as consumable supplies, but buy some first to TEST! Save money but do it smart, don’t be silly.

For patch cabling 10Gbps Copper Twinax Direct Attach works great for short ranges and isn’t expensive, but the length is limited and they get thicker & more sturdy and thus unwieldy by length. It does have it’s place and I use them where appropriate.

Isn’t this dangerous?

Nope. Technology wise is perfectly sound and nothing new. Project wise it delivers results, fast, effective and without breaking the bank. Functionally you now have all the bandwidth you need to stop worrying and micromanaging stuff to work around those pesky bandwidth issues and focus on better ways of doing things. You’ve given yourself options & possibilities. Yay!

Perhaps the approach to achieve this isn’t very conventional. I disagree. Look, anyone who’s been running projects & delivering results knows the world isn’t that black and white. We’ve been doing 10Gbps for 4 years now this way and with (repeated) great success while others have to wait for the 1Gbps structural cabling to be replaced some day in the future … probably by 10Gbps copper in a 100Gbps world by the time it happens. You have to get the job done. Do you want results, improvements, progress and success or just avoid risk and cover your ass? Well then, choose & just make it happen. Remember the business demands everything at the speed of light, delivered yesterday at no cost with 99.999% uptime.  So this approach is what they want, albeit perhaps not what they say.

The Hyper V Amigos Showcast Episode 3: Live Migration


Here’s the 3rd episode of the Hyper-V Amigos show cast. As Carsten was overwhelmed with work (running your own business is very hard work) and had some issues with his storage spaces lab due to testing we’re discussing live migration optimizations in this installment.

 Carsten Rachfahl and I had a lot of fun again, even during the second take, yes we needed one. Apparently these software thingies require me to click on “record” Smile as there is no intelligent agent yet to act on my intention.

Carsten & I discussing & showing some live migration optimizations

 

I have written many blog posts on this subject already and I’m sure I’ll write more. Optimizing the use of the hypervisor (Hyper-V) across the entire storage, compute/memory & networking stack is one of my specialties and I enjoy this part of my job very much. I also like to share this information as real.

I’m sure you’ll agree that Hyper-V has come a long way in short period of time and I’m pretty sure we’re going to see Microsoft continue this pace for quite a while.

I have a blog post coming out (it’s in the queue) on my 4 top recommendations for optimal live migrations but here’s a search of relevant blog posts on this topic, and we referred to some of them during our show cast:

https://workinghardinit.wordpress.com/?s=Live+Migration&submit=Search

When you’re done reading al these posts on live migration you’ll have earned a nice refreshing beverage of your choice Mug.

One more thing, if you like these show casts let us know! Last but not least, I’m doing a demo heavy (only) session at ITProceed on June 12th 2014. Many local experts, community members  and I will be around afterwards to discuss these technologies.