Details of VMware View Reference Architecture - Part I

Wednesday, December 17, 2008 Category : 3

News came out today about the View Manager Reference Architecture papers. We have been waiting for some further technical details about scaling and best practices, so what was released and what does it mean?

First things first, where to do you get them? Well you have to register for them. VMware have enough issues with where to find technical documents and they have gone and introduced yet another method? Thankfully the pack is listed on the Technical Resources page where people would naturally go looking for reference architectures; however this simply presents a link back to the registration page! 

Okay, lets be clear, you are being evil VMware. Do marketing really think that someone is going to want to read these documents and not already have some form of contact with VMware that they can track and follow to pursue sales leads. Either you have already purchased it, downloaded the evaluation (which collects more information) or you obtained it from a VMware sales person. Come on, you can’t be so desperate for sales leads that you think this is going to add any real value to your pipeline. Okay, I feel better to have that off my chest.

Here are the documents and their descriptions.
  • VMware View Reference Architecture - A guide to large-scale Enterprise VMware View Deployments
  • Guide to Profile Virtualization - Examine traditional approaches to user profiles and discover a new way to approach user profiles in a heterogonous environment while delivering the best overall user experience.
  • Windows XP Deployment Guide - This guide suggests best practices for creating Windows XP-based templates for VMware View based solutions and for preparing the templates for use with VMware View Manager 3.
  • Storage Deployment Guide for VMware View - Review a detailed summary and characterization of designing and configuring the EMC Celerra NS20FC for use with VMware View.
In this “Part I” we are going to dive into the main document, the Reference Architecture.

The document consists of 36 pages detailing the infrastructure required to create a building block which can support 1,000 users. Also included is the components to integrate 5 building blocks, to support 5,000 users. Its vendor agnostic (except reference to EMC), so you can put your vendor of choice into each component, and they might bring some special additional feature to the table (but these are not considered). The first 14 pages rehash lots of features and functions of VMware View without actually giving much detail about the reference architecture, but its worth having there though.

The architecture is based on large-scale, LAN-based deployment, so it does not delve into the WAN acceleration space. Recommended bandwidth is 100-150Kbps without multimedia and latency below 150ms, so nothing new or changed here.

When describing virtual disk management the following is stated.
“Because VMware View Manager supports a variety of back ends, such as VMware View virtual desktops, Microsoft Terminal Services, Blade PCs, and ordinary PCs, it is recommended that a robust profile management solution be implemented. Profile management solutions such as RTO Virtual Profiles or Appsense can work in place of, or in conjunction with, a VMware View Composer user data disk. Profile management helps to ensure that personal settings will always be available to users who are entitled to multiple back-end resources, regardless of the system they are accessing. Profile management solutions also help to reduce logon and logoff times and to ensure profile integrity.”
This is an important point and one I will come back to in a Part II. I met today with Appsense to nut out some particular nasty VDI use cases and they have some great technology for VDI (which I started looking at back in Oct 2008 when VDM 2.0 was in Beta).

Here is what the building block looks like.



Each block consisted of a blade chassis with 16 hosts split into two clusters, A & B. Cluster A was for testing a dynamic work load of office type workers which consisted of 25 Persistent Full Clones, 225 Persistent Linked Clones and 250 Non-Persistent Linked Clones. Cluster B for a more static load of task-oriented workers and it consisted solely of 500 Non-Persistent Linked Clones. 

There was one vCenter for each block of two clusters. The blades were dual quad core 2.66 Ghz with 32G of RAM. It’s a little hard to understand the networking configuration of the blades, because it’s laid out weird in the parts tables. 10G interconnects were not available when they did the test and it utalises iSCSI for the storage fabric. There is no clear detailing of the networking apart from a logical diagram and some scattered info of how it hangs together, this could be improved through further diagrams or some more details. 

For the 1,000 desktop tests two VDM Connection Servers were used, for the 5,000 there was five. Desktop connections were direct hence no SSL.

All of the supporting servers (VDM, AD, SQL, vCenter etc) where virtual but resided outside of the block.

The storage was a NS20FC with a CLARiiON CX3-10F backend with 30 x 300GB 15K FC disks. It was very hard to tell but it looks like each blade enclosure was directly connected via Ethernet to the SAN. Seven Datastores were created for each cluster, which gives around 64 VMs per Datastore.

The good thing here is that these are all sensible and common components which can be achieved in the real world outside of the lab where money for things like RAM sticks is irrelevant. 

Provisioning results are detailed. The 500 linked clones in Cluster B took 161 minutes, or just under 33 seconds each, that’s nice and fast. One interesting point that was highlighted is that each data store gets one replica for its clones to use and that different pools will share the same replica if they are off the same Parent version (snapshot), sweet. I knew they were copied per datastore but not that they were shared across pools.

Load testing was done with normal MS office applications plus Acrobat, IE and real time Anti-virus, performing actions for 14 hours. Each desktop had a 8Gb disk and 512Mb of RAM. 

What was the result? 
“1,000 users can easily be maintained by this architecture [with fast application response time] using the provided server, network, storage resources, and configuration”. 
Application response times are detailed and they look fine, but there is no comparison to  benchmark against.

In the performance testing neither cluster went over 50% utilization. The VM to core ration is just under 4:1 which is on the money. Given the CPU utalisation it looks like you could got to 5:1 and run around 640 machines, however more RAM may be required. The vCenter and SQL server managed fine with the load. Likewise the storage in terms of CPU and IOPS was fine with spare capacity. 

So what’s missing. 

Well a glaring omission is any metrics on memory utalisation. As most installations are memory rather than CPU bound it would have been interesting to see how close to the wire the memory footprint would have been? What about over commit, how much transparent pages sharing was there? Sure it’s a reference platform but they would be very helpful figures to see, certainly no less helpful than the CPU ones. Are VMware trying to hide something here? I doubt it, but it does beg the question then why not include it?

Lastly it would have been good to see a lot more configuration data, how the storage was laid out, some more of the network connectivity. Yes its trying to be vendor agnostic but if you can include VLAN ids you can include a storage design. There is a lot of this information in the other reference paper on the NS20, but people are not going to look their for high level stuff if they are not condsidering that SAN.

There you have it. In Part II we will look at some of the other documents.

Rodos

VDI and WAAS

Tuesday, December 16, 2008 Category : 1

Further to my previous post on Is network acceleration useful for VDI?. Cisco have a post up on their Data Center Networks blog about VDI. In the white paper linked off this post it states

The joint Cisco and VMware solution optimizes VMware VDI delivery and allows customers to achieve the benefits of VMware VDI by providing the following features:
  • Near-LAN performance for virtual desktops over the WAN, improving performance by 70 percent
  • Increased scalability of the number of VMware VDI clients, increasing the number of clients supported by 2 to 4 times, and massive scalability of VMware VDI and VMware VDM data center infrastructure
  • 60 to 70 percent reduction in WAN bandwidth requirements
  • Optimization of printing over the WAN by 70 percent, with the option of a local print server hosted on the Cisco WAAS appliance
  • Improved business continuity by accelerating virtual image backup by up to 50 times and reducing bandwidth by more than 90 percent
Just like other vendors some bold claims. Some of these are simply distractions, improving transport of virtual image backup across a WAN link for DR purposes is not really a VDI issue, thats stretching the friendship and moving into marketing spin. However I have seen some of the internal Cisco analysis on the acceleration of RDP/VDI and it does look to stack up. Hopefully in the new year I will have completed some testing.

As mentioned in my post on Cloud,  the need and adoption of WAN acceleration is going to heat up next year. We all need to pay attention to this space, with the usual eye of lets see the reality. If they vendors are going to keep spruiking it, fair game that we hold them to account for deeper details.

Rodos


Cloud computing conference report

Monday, December 15, 2008 Category : , 1

What would a Enterprise, in particular one using virtualisation, take away from a Cloud computing event? What if the speakers were from Cisco, Yahoo, Google, Microsoft, Baker & McKenzie and Deloitte Digital? Well two weeks ago I went to such an event, took lots of notes and engaged in some interesting discussions. Here is what some of what occurred and my updated thoughts on the Cloud space.

The event was held by Key Forums and was help in Sydney, Australia on the 3rd of December. Billed as a one day, comprehensive conference, the expectation was

This conference will kick start your Cloud strategy and will get you up to speed on what the main players, critics and users think about the potential of Cloud Computing. It will give you the opportunity to discuss your issues surrounding Cloud Computing with your peers and our expert panel of speakers.
The speakers were local heavy hitters and an impressive list. Some of their presentations are available online and worth a look. The Google one was originally public but has been pulled at Google’s request. Of course the presentation from the legal firm was never public, go figure.

Missing were the industry analyst types, such as IDC and Gartner and as a result there was not a lot of this is what the industry and market are doing. Instead what was presented was what the speakers form the organizations are thinking about in terms of direction in the cloud space. If you were to pick the vendors in the Cloud segment the only two vendors missing were Amazon (not much of a presence in Australia) and VMware. Amazon is fare enough, they don’t have much of an interest in Australia, however I think it would have been good to see VMware there, as I believe they have a lot to contribute to the space.

What were the highlights then, as there is way too much to report on in detail in this forum and format?
  • All of the vendors see a strong growth in the various forms of Cloud computing. To paraphrase Anna Liu from Microsoft, “You either embrace and anticipate these changes or get left behind”. For example Cisco are one of the biggest users of Salesforce.com, the NY times used Amazon and Hadoop to convert 4TB of images to text, in just 24 hours, Gmail has over 10 million paid accounts and Cisco now own Webex (a SaaS based app) and its in their list of top return on investment acquisitions.
  • There was a reasonably common view of what cloud computing is and is not, yet each company had a particular slant to their area of the cloud (which you would expect). The breakdown was typically your SaaS, PaaS and IaaS. From the IaaS site Cisco were certainly the most strong as you would expect, although it was termed “hosting” which was a little strange. In terms of alignment with VMware Cisco was very close, even mentioning the recent visit my Paul Maritz and discussing hybrid cloud of on and off premise.
  • Both Cisco and Yahoo spoke about virtualisation and the changing space of the server world. Keith Marlow from Yahoo! made the obvious but insightful comment that the overhead of virtualisation was a constant and due to the increasing power of processors this constant was becoming irrelevant. Keith showed a picture of the Yahoo! datacenter with 20,000 nodes. With all of that processing power sitting there, it makes economic sense to sell some of the capacity. Kevin Bloch from Cisco spent some time talking about virtualisation and increasing core counts and how this was changing the game in data centers.
  • Cisco made a good observation that WAN acceleration technologies are going to be important as clouds are built and federated with more and more data flowing around. Of course WAAS was mentioned.
  • Security was mentioned multiple times as issues being presented as a concern by the market place. Whilst everyone acknowledged and respected this, the responses were generally aligned. The view was that currently people trust their banking and credit cards to the Internet and forms of cloud, so we are already starting to see acceptance. Comparison was made to the level of skills, quantity of people and attention to the problem that the providers give compared to the usual very small set of security staff within an organization. (However as one college reminded my today, they have much larger attack surface to cover too).
  • The concept of access from any where at any time from any device came up a number of times. This links in very well with the VMware vision for View and access to your desktops, applications and data from anywhere at any time.
  • Openness was certainly a theme from Yahoo! and Google. Open APIs, or Open Standards, being able to embrace and extended were seen as important. 
  • Certainly the presentation from Microsoft was the best, from my view anyway. Anna was not only a good speaker but had some good insights into the space. I recommend flicking through the presentation and I would love to hear her speak again on the topic. Some great comments such as just because you have control of an SLA, that is, its in house, does not mean that the SLA is any better than it might be if you don’t control it, such as in the cloud. A good contrast was made between control and economies of scale. A car gives you lots of flexibility for transporting things anywhere you want but does not have as good economy of scale. A freight train has great economy of scale but comes with a constraint of controlling flexibility. This balance of control vs scale was compared to build vs buy and on premise vs in the cloud. The Microsoft way was to move to services from the cloud (SaaS) or rewrite applications (PaaS). Around PaaS the view is strongly aligned with .net and hence Azure. Anna indicated that moving is “non trivial” and that there is going to be on premise and cloud models for quite a while. 
Here is a picture of the Yahoo! room with 20,000 nodes.



So if this conference was to help one understand and think move about the Cloud computing space, what influence did it have? Did it change or enhance my thinking on Cloud? In some ways yes, and I recognize that I too come at cloud from a very specific angle.

Here is my current positioning.
SaaS is going to be a massive market. However in the main this adoption is going to be more in growing new services that are tactical rather than the main game of organizations core business processes. Yes Cisco may move to Salesforce.com but for most enterprises core elements are going to stay in house. It’s the new systems and non core that are going to see the most growth in SaaS.

When that project team needs a new intranet site, rather than waiting two weeks for IT to not deliver, they will put their credit card number into a website and be up and running in 10 minutes.

The challenge for VMware here as well as the opportunity is to capture some of this space with Virtual Appliances. If a mature set of Virtual Appliances can be available through the market place; if these can be downloaded from within the management environment painlessly; and if they can not only describe their service levels, backup and disaster recovery requirements (vApps) but also implement them automatically (AppSpeed, Data Recovery Appliance, SRM) VMware could be onto a good slice of this pie. Put your credit card in, download the service and run it locally in your own security model, owning the data. You can even still have the provider maintain the application as part of a maintenance agreement. Most of the benefits of SaaS without many of the current concerns and limits. VMware need to lead by example here.

PaaS is the challenging space. Microsoft is going to push .Net real hard, and that means Azure. The challenge for all of the players is to support open languages such as Hadoop and Ruby on Rails. This strategy is good for customers in the enterprise. If they develop their own applications in these open languages they can execute them internally on their own clouds. After all a key element of VDC-OS is running the workloads of today and tomorrow. With VDC-OS you can run mixes of work loads and change them on the fly, one day 10% of your cluster might be running Hadoop nodes and tomorrow, to scale up for a specific project work load, it may be 30%. Even better because you have written to an open standard you can go to a provider in the open market to buy capacity for short or medium term, if you really need to scale up. Even if you run that application out in the external cloud, if there is a problem, or for testing, or for DR, you can always run it in house on your own cloud if needed. VMware need to work hard here to not let the ISV market get away from them. Maybe that’s why Paul Maritz can’t stop saying Ruby on Rails.

IaaS is VMware’s sweet spot. The enterprises know they need to move to the benefits that cloud and utility based computing can bring. They want to run like Google and Yahoo! The challenge is how to do this in today’s environment and that’s where VDC-OS, vCloud and vApp come into play. Running internal clouds, federating them, running the workloads of today and tomorrow, its not just a dream, its like Christmas, you know its coming and its not far away. The problem for VMware is to not been seen like Azure and be another closed shop. That’s why it’s good to see vApp being based on OVF. We know VMware is the best system for running workloads, if we can keep the portability of workloads it means the best technology wins. If it all goes closed, the best marketing company wins, and that is not VMware. Also VMware need to keep tight (like they already are) with complementing technologies. Networking is going to play a huge role in enablement of the cloud, from things like split VLANs to WAN acceleration.
If you are in Australia and interested in cloud computing like I am. I would recommend you put March 25th, 2009 in your calendar. IDC are holding a Cloud Computing Conference on this day in Sydney. See, aren’t you glad that you read all the way to the end of this post! You can register for free as an early bird attendee. 

Also Richard Garsthagen in revealing details of VMWorld Europe 2009 has state that it will “probably” have a special pavilion for vCloud providers (2:20).

If you have some thoughts on the Cloud space, leave a comment.

Rodos

Linked Clones Not A Panacea?

Thursday, December 11, 2008 Category : 7

Over at vinternals Stu asks if linked clones are the panacea that a lot of people are claiming about the storage problem with VDI? I say yes, however we are moving from designing for capacity to designing for performance, and VMware have given us some good tools to manage it. Let me explain a bit further.

Stu essentially raises two issues.

First, delta disks grow more than you think. Stu considers that growth is going to be a lot more than people expect, citing that NTFS typically writes to zero'd blocks before deleted ones and there is lots of activity on the system disk, even if you have done a reasonable job at locking it down.

Second SCSI reservations. People are paranoid about SCSI reservations and avoid snapshot longevity as much as possible. With a datastore just full of delta disks that continually grow, are we setting up ourselves for an "epic fail"?

These are good questions. I think what this highlights is that the with Composer the focus for storage for VDI has shifted from an issue of capacity management to performance management. Where before we were concerned with how to deliver a couple of TB of data now we are concerned with how to deliver a few hundred GB of data at a suitable rate.

In regards to the delta disk growth issue. Yes, these disks are going to grow, however this is why we have the automated desktop refresh to take the machine back to the clean delta disk. The refresh can be performed on demand, as a timed event or when the delta disk reaches a certain size. What this means it that the problem can be easily managed and designed for. We can plan for storage over commit and set the pools up to manage themselves.

To me the big storage problem we had was preparing for the worse case scenario. Every desktop would consume either 10G or 20G even though most only consumed much less than 10GB. Why? Just in case! Just in case one or two machines do lots of activity and because we had NO easy means of resizing them we also had to be conservative about the starting point. With Composer we can start with a 10GB image but only allocate used space. If we install new applications and decide we really do need the capacity to grow to 12GB, we can create a new master and perform a recomposition of the machines. Now we are no long building for worse case but managing for used space only. This is a significant shift.

So happens today there was a blog posting about Project Minty Fresh. This installation has a problem with maintaining the integrity of their desktops. As a result they are putting a policy in place to refresh the OS every 5 days. This will not only maintain their SOE integrity but also keep their storage overcommit it check.

In regards to SCSI reservations. I do believe that the delta disks do still grow at 16MB and not some larger size. So when the delta disks are growing there will be reservations, and you will have many on the one datastore. Is this a problem? I think not.

In the VMware world we have always been concerned about SCSI reservations because of server work loads. For server work loads we want to ensure fast and more importantly predictable performance. If we have lots of snapshots that SQL database system which usually runs fine now starts to behave a little differently. Predictability or consistency in performance is sometimes more important than the actual speed. My estimation is that desktop workloads are going to be quiet different. In our favor we have concurrency and users. All those users and going to have a lower concurrency of activity, given the right balance we should have a manageable amount of SCSI reservations, if not we rebalance our datastores, same space, just more LUNs. Also unlike servers, will users be able to perceive any SCSI reservation hits as they go about their activity. Given the nature of users work profile and that any large IOs should be redirected not into the OS disk but into their network shares or user drives the problem may not be as relevant as we may expect.

What Stu did not mention and we do need to be careful of because it can be the elephant in the room is IO storms. This is where we really do have some potential risk. If a particular activity causes a high currency of IO activity things could get very interesting.

Lastly, as Stu points out, statelessness is the goal for VDI deployments. Using application virtualisation, locking down the OS to a suitable level and redirecting file activity to appropriate user or networked storage is going to make a big impact on the IO profile. These are activities we want to undertake in any event, so the effort has multiple benefits.

I too believe you need to try this out in your environment, not just for the storage requirements, but also for the CPU, user experience, device capabilities and operational changes. VDI has come a long way with this release and I do strongly believe it will enable impactful storage savings.

What I really want is the offline feature to become supported rather than just being experimental. Plus I want it to support the Composer based pools. There is no reason why it can't and until then, there is still some way to go before we can address the breadth of use cases. However there are plenty of use cases now, which form the bulk, to sink our teeth into.

Rodos

Updated VMware Technical Resource documents listing

Category : 0

Two new documents added to the "VMware Technical Resource documents listing" on VMTN.

At version 16 there are now 197 documents listed with abstracts for searching.

Added Storage Design Options for VMware Virtual Desktop Infrastructure
Added Using IP Multicast with VMware ESX 3.5

http://communities.vmware.com/docs/DOC-2590

Rodos

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