Benefits of iSCSI Over Fibre Channel
7/1/2008 -- Comments

Our upcoming chat today on benefits of iSCSI and Virtualization led me to some quick research to see what I could find. The first hit was for a Dell Whitepaper on why iSCSI is the best storage for virtualization. Turns out this is a whitepaper that I reviewed internally before it was published about a year ago.

I was a long time fibre channel user and thought that some of the points in the paper were a bit harsh. The funny thing is that reading it now I agree with it much more. The paper didn't change, but my experience in the last year with iSCSI has changed me. I really do think that iSCSI is easier and the performance concerns that I had, for the most part, don't concern me anymore. Although I must admit that I still like my CX3-80 fibre channel storage.

Todd - Comments




Cluster Filesystem for Hyper-V
6/17/2008 -- Comments

I ran across Scott Lowe's blog entry on Melio FS, Hyper-V, and VMware ESX earlier today. Scott talks about his discussion with Jeff Woolsey - Senior Program Manager for Virtualziation at Microsoft - while at Tech Ed. Specifically how Microsoft has allowed storage partners to create a cluster file system that can be used by Windows 2008 \ Hyper-V. Such a cluster file system could enable the VMFS type functionality of having multiple physical hosts access a shared disk at the same time. This would remove the requirement of one LUN for one VM when doing quick migration with Hyper-V. Specifically Sanbolics' Melio FS was identified as capable of doing this.

I think this is excellent news and means that Hyper-V customers will have a cluster file system option for their Hyper-V hosts. This can greatly simplify storage management when you have more than just a few VMs. On the downside is the additional cost of such a cluster file system. There is not pricing listed on the Sanbolic website, but the Network World article states that the price is $5000 per host. If the cost is anywhere near that, then the price of VMware's ESX doesn't seem that bad in comparison to Hyper-V - assuming that you need or want the cluster file system capability.

Todd -- Comments




Support of Microsoft on VMware VMs
6/13/2008 -- Comments

A question that has come up many times over the last several years is that of support of Microsoft software when running in VMware VMs. This blog entry by Mark Bowler at Liquefying IT has some great stats that show a majority of people are running Microsoft in their VMs and that the support picture is fuzzy for some of them. If you have a Microsoft Premier Support agreement they will support you when running on VMware, but they do reserve the right to have you reproduce it on hardware. Mark then points out a new program from Microsoft to provide validation of virtualized environments which would then lead to the ability for customers to receive technical support.

The program is called the Windows Server Virtualization Validation Program (SVVP) and currently lists four other virtualizaiton vendors: Citrix, Novell, Sun, and Virtual Iron. Notably absent from the list is VMware.

Dell provides support for Microsoft operating systems running in VMware VMs which is detailed in this customer letter and on VMware's webpage on Support for Microsoft Software in VMware Virtual Machines:

"For customers who purchase OEM VMware products with Dell hardware and Dell Gold Enterprise Support or Dell ProSupport, the vendor provides end-to-end support—including the VMware software and certified Microsoft operating systems that are run within virtual machines."

Todd -- Comments




Pictures of R805s Arriving in Lab
06/11/2008 -- Comments

Our shipment of four brand new PowerEdge R805 servers arrived yesterday afternoon. We got them loaded up with Quad-Core AMD Opteron 2356 2.3 GHz processors, 64 GB of RAM, and a Quad-Port Intel NIC (in addition to the four onboard NICs). I just love opening up new servers and I was pretty excited to open these up and get them in the rack - but not as excited as this.



Here is a picture of the new servers in our lab from this morning. I have also uploaded a few more pictures in the Photo Gallery that show the inside of the R805, the included VMware ESX Server 3i, and the servers installed in the rack.

The only thing left to do now is use VMotion to get some VMs onto these systems and put them to work.

Todd -- Comments




Storage Choices for Virtualization Can Be Easy
06/10/2008 -- Comments

After spending the last few weeks looking into which server to choose for virtualization, a natural next question is – What should I use for storage? I think that the answer here may be easier in some ways, but more complicated in other ways.

Mark Farley, on the InsideIT blog, highlighted a recent video by Darren Thomas, General Manager of Storage – aka Chief Storage Guy - here at Dell, that focuses on how storage virtualization works well with server virtualization. Just as VMs are able to use live migration to move from one physical server to another, virtualized storage can move those same VMs from one storage array to another. The result is that you have a tremendous amount of flexibility and availability.

There are three major categories for storage: local, iSCSI, and Fibre Channel. There are lots of choices within these, but I think that when deciding what to use to support your virtualization servers this is the best starting organization. If you are going to only have one virtualization server (or one per location) then local storage will work just great. If you already have an existing fibre channel SAN and existing expertise to manage it, then fibre may be the best solution for your virtualization server farm. Everybody else should probably take a really hard look at iSCSI.

Within the iSCSI category at Dell we have three areas to pick from: PowerVault MD3000i, Dell EqualLogic PS Series, and Dell | EMC AX and CX iSCSI arrays. I think that the decision here also breaks down very similar to how we arrived at the type of storage. For smaller deployments or those that do not need array level features like replication the PowerVault MD3000i (with an attractive entry-level price) is a good choice. For customers that already have some Dell|EMC fibre channel or iSCSI it might be a good idea to extend this environment with additional iSCSI for your virtualization needs. I think that the Dell|EqualLogic PS series is a strong contender for all other solutions.

Of course it’s really a bit more complicated than this, but this is the way that I frame up a conversation around storage for virtualization solutions.

Todd -- Comments




Wiggle Room in Deciding on a Virtualizaiton Server
06/05/2008 -- Comments

What is the best server for virtualization? This is a question that comes up often in discussions, although it is sometimes phrased differently. It might be "How many NICs do you recommend for ESX?" or "How much RAM can you put in an R805?" or "Are blades the most power efficient server?". The really cool thing is that the answer to all of them ends up being the same - If you can tell me what you are trying to do, and the key requirements that you have, I can give you the best answer. Sometimes you need tons of RAM, sometimes you oodles of NICs, and sometimes you are looking for the best value.

We can give you some basic guidance and even provide you with reference architectures, but ultimately everybody has to customize their virtualization solution based on their needs. To provide you with the ability to be able to customize, you have to be educated about what your choices are what the ramifications are for each choice. That's what this focus topic on Selecting a Virtualiation Server has been all about. Connecting people with the information as well as each other for discussion about the process. This played out in each of the three chats that we did, and can continue on the discussion threads.

This really isn't anything new in the IT world. Almost all solutions have required a certain amount of planning and sizing that was specific for each organization. The advantage with virtualization is that there is more wiggle room to adapt and learn as you go. Because virtualization provides a layer between the VMs and the physical servers, things can be changed, modified, tuned much more easily than without virtualizaiton. If you find that a server is overloaded with too many VMs, you can use VMotion to move some to another server. If you find that you are out of capacity, you can add another server to the farm and redistribute the VMs to take advantage of the new capacity - without any downtime.

Use this community to keep the discussion going about what the best server is for virtualization - all questions around this topic are welcome. The opportunity to interact with your peers and find out why and how they made their decisions is really the best answer to a question that has a different answer for everybody.

Todd -- Comments




Inside IT Video is Still True
6/2/2008 -- Comments

I didn't get a chance last week to draw attention to the nice video that Marc Farley put up on the InsideIT blog last week about our TechCenter web chats. Marc is a regular attendee of our weekly chat sessions and he is also the lead blogger on InsideIT. The video is cool, short, and just as relevant this week as last. This week's chat (Tues 3 PM CST) will be about when to select blades for your virtualization server platform.

Todd -- Comments




Oodles of NICs for ESX
5/30/2008 -- Comments

Back in the ESX 2.5 days it was a common recommendation to have at least 3 NICs for ESX. One NIC each for the service console, VMotion, and VMs. It was really a waste for many to have to dedicate an entire NIC for the low network traffic to the service console. Then with ESX 3 the networking features became more flexible, and you could easily setup the service console to share a NIC with VMotion or the VMs.

The M600 and M605 blades for the Dell M1000e blades chassis now have two on-board NICs and the option to add two more I/O cards, each with two ports of either Ethernet or fibre channel. This means that you can have four NICs and two fibre channel ports for storage OR six NICs with 2 dedicated to iSCSI for storage. The four available NICs for VM data traffic is usually enough, although I admit there are always exceptions.

So if the I/O options on the blades are not enough there are options with the R805 and R900 and R905 that offer oodles of NICs. Specifically the R805 has four on-board NICs and four PCI slots. Filling these slots with your required mix of quad-port NICs and dual-port fibre channel HBAs would be a great solution for environments that have high requirements of physical NICs to support their VMware environment.

Todd -- Comments




Ultimate Power Efficiency with Blades and Virtualization
5/29/2008 -- Comments

A recent thread here on delltechcenter asked for a power consumption comparison between the PowerEdge 1950 1U rack mount server vs the PowerEdge M600 blade. It turns out that there are a few whitepapers that have been done on 2950 power consumption and a big study on the blades power consumption - but nothing I can find that directly compares the two. The best way to get a comparison between just about any current or recent Dell server is to use the Dell Datacenter Capacity planner. It allows you to build out a rack of servers and get an estimate of power consumption.

If you use similar configurations for 16 PowerEdge 1950s and a full M1000e chassis (16 blades) then the blades configuration will consume less power. So you can save a significant amount of power by going with blades over similar traditional rack mount servers.

If you combine the efficiencies of the blades with the efficiencies of running lots of VMs on a single physical server - you might have the ultimate in power efficiency. This is one reason to use blades for virtualization - we'll be chatting about this and other reasons next week in our TechTuesday chat.

Todd -- Comments





Virtual Exchange Server for Home
5/23/2008 -- Comments

As many of you have probably figured out by now, I've spent a lot of time working with Exchange in VMs. Some of that time was spent explaining to peers, users, customers, and family members just exactly why in the world anybody would want to put Exchange into a VM. (To be honest - I don't think I was able to convince my mom.)

Early this week I ran across an entry titled Eight Good Uses for VMware and Other Virtual Machine Software on the TechnologySpeak blog. Number three on the list - Running an Exchange Server to Keep Outlook Synchronized. Turns out that having a local Exchange Server on your home network can make it much easier and faster to sync up Outlook across the 4 or 5 systems that you have at your house. If you are reading this entry, then I would bet that you have at least that many.

The only caveats that the blog calls out:

"The initial setup is a little bit tricky if you're not familiar with installing servers and server software, but once you get it going, it works very smoothly. Also, for many, the initial cost of buying the software might be prohibitive."

Meaning that you have to be a geek or a professional Exchange admin or both. On the cost perspective I initially thought that it might be really really prohibitive, but a little digging around and it looks like Microsoft Small Business Server licenses aren't too bad. The list price for SBS R2 is $599, which includes the Windows Server OS, Exchange Server, and 5 CALs.

With the memorial holiday weekend coming up, I think that everybody should take a break from the grill and spend some time getting your own virtualized Exchange Server setup for the house.

Todd - Comments





Massive IOPS on ESX
5/22/2008 -- Comments

They performance guys over at VMware have announced some really impressive IOPS testing results. Using three CX3-80 storage arrays they were able to push over 100,000 IO Operations per second from a single 4-socket server running ESX 3.5. Additionally, they reported the latency numbers which look very good as well.

I find this very interesting because it is in line with results that Kong and I got in our Exchange 2007 on ESX testing we did last year. We found that you could size storage for Exchange VMs the same as you size storage for Exchange on physical servers (up to the 2000 users in a single VM that we tested). Exchange is I/O intensive and is sensitive to any increased latencies. So while we didn't test a workload of 100,000 IOPS, we did see good storage performance with an application that is very sensitive to these kinds of things.

The other thing that I like about this test is that it is cool. As evidence I point to the cool graphs they included and the 495 15K RPM disks that were used.

Todd -- Comments





VMotion Compatibility and Server Selection
5/21/2008 -- Comments

On the TechTuesday chat yesterday the topic was Selecting a Server for Virtualization, and we had an excellent discussion. One of the points that came up was the importance of understanding VMotion compatibility between different servers. On easy rule is that it is not possible to VMotion between AMD and Intel processors. As these are completely different processors in many respects it is easy to understand how it is not possible to move a running VM from one to the other with no downtime. The next aspect that VMotion will not work across different generations of processors. The difficulty here is that processor generations do not always line up with Dell server generations. So even if you have all Dell 9G servers, there are cases where VMotion will not work.

It really comes down to the instruction set that each processors is using. A running VM has identified the processor that it is running on and is expecting a certain instruction set to be available. If this were to suddenly change in the middle the OS would not be able to cope or adapt and would most likely crash. There has been some work done to improve the situation - but as of today it is still an issue.

The answer to this problem is the compatibility matrix that our virtualization engineering team has put together and updates as new servers are released. It is important to consider this matrix when selecting a server if VMotion is in use.

Todd -- Comments




Bumping Into It on VMTN
5/20/2008 -- Comments

I just ran into a thread on VMTN that is exactly what we are hosting a chat on later today. The VMTN thread is titled Physical Hardware Recommendation, but I am calling the same topic Selecting a Virtualization Server. Very coincidental that this thread was started today and it even specifically asks about 2950s and R900s. So for the record - this VMTN thread was not a planted thread by me or some secret Dell conspiracy. I do have to confess that it was Scott that spotted this thread first and he deserves the credit (Again!).

Todd - Comments




The Best Server for You
5/19/2008 -- Comments

For the past three weeks, we at the Dell TechCenter have been focused on the decoder ring for systems management. Starting today we are going to tell you what the best server is for virtualization. The reason it is going to take three weeks is that the answer for everybody is different. So we are going to talk about key factors, advantages of one type of server over another, and learn from the decisions and thought processes of each other. We are simply hosting the conversation and I do not have a "favorite server" -- although I must admit that I used to lean heavily towards 2-socket servers.

The decision for most seems to come down to 2-socket, 4-socket, or blades servers. I hope that we end up expanding the conversation and talk about lots of other possibilities including storage options, hypervisor options, and who knows what else.

In order to get things going are going to have some chat sessions, there is a topic home page, and a server selection matrix page to specifically lay out the facts about each type of server. I've started the page off with 2-socket, 4-socket, and blades as server categories with some basic tech specs and advantages for each type. This page will grow as additional pros, cons, and others ideas come up.

Todd -- Comments




VMmark Results Point to Best Performance
5/15/2008 -- Comments

New VMmark benchmark results highlight that the best performance for a single server is a 4-socket (or 16 cores with Quad-Core processors). This means that the R900 and R905 are at the top of the list, with the Intel based R900 slightly ahead of the AMD based R905. So if you absolutely need the most performance possible from a single server - then this is the way to go.

A little bit of analysis could lead you to believe that the 2-socket (or 8 core) servers are actually better performing. The VMmark score for the 4-socket R900 is 14.23 with 10 tiles, but the VMark score for the 2-socket 2950 III is 8.47 with 6 tiles. So on a per socket basis, the two-socket 2950 III is actually providing more performance. The same holds true for the two-socket M600 blade and two-socket R805 2U server.

There is much more to choosing a server than the results of a single benchmark, but I think that these results are fair barometers of performance. In general performance does not scale in a linear fashion when moving from 2-socket servers to 4-socket servers, and this seems to hold true with virtualization.

Todd -- Comments




Upstream Ports and Blades
5/13/2008 -- Comments

A recent discussion in the hallway here lead to a really cool reason to use blades for virtualization. The Dell M1000e blade chassis and the M600 and M605 blades support up to six fabrics - meaning that you can have some combination of Ethernet and fibre channel networks totaling six. This provides enough networks such that the service console, VMotion, and VMs can all have dedicated Ethernet networks - with enough left over for iSCSI or fibre channel storage networks.

The really cool thing is the dramatic reduction in need for Ethernet and/or fibre channel upstream ports. All of the service console traffic can be handled by a single upstream port. If the VMotion traffic is strictly between blade servers, then the upstream ports of this network are not needed. Even if you need to VMotion out of the chassis, the upstream ports needed on your network infrastructure will still be greatly reduced. If you had sixteen standalone servers (like the 2950) then each one would need a port for VMotion, but with the blade chassis you could just up-link what you thought you needed in terms of bandwidth - which would be less than 16 (probably more like 2 or 4).

Additionally M1000e blade chassis can be interconnected via the Cisco Catalyst Blade Switch 3130G or 3130X modules and managed as a single switch via their Virtual Blade Switch technology. So with multiple M1000e chassis' the savings in terms of upstream port costs can really be big.

Todd -- Comments




Decisions Decisions Decisions
5/9/2008 -- Comments

With the release of the 2U, 2-socket R805 and the 4U, 4-socket R905 (both AMD based servers) and the already existing 4U, 4-socket R900 (Intel based server) now is a really good time to be looking for a server to run your virtualization farm on. All three are excellent choices and could be the right server. To determine which one depends on lots of things. I'm looking for reasons to choose one over the other (let me know your thoughts). We will be putting together some information to help people decide here on TechCenter and hosting some chat sessions to enable discussion.

Specifically, I ran across this article from The Register that I think has a pretty good take on the R805/R905 Virtualization announcement from a couple of days ago. They point out all of the server options as well as the virtualizaiton services that were a part of the announcement on Tues.

Todd -- Comments




The R805 is Here
5/8/2008 -- Comments

I leave for vacation for a few days and all kinds of cool stuff is announced (although I did make it into the office a couple of times while on the beach). What I think is a really great server for virtualization is now on the website where you can configure and order it. The new PowerEdge r805 is not just a new version of the 2950 or 2970. It was designed with virtualization in mind and has the features to back it up. It has 16 memory DIMM slots, 4 embedded NICs, plus four more PCI slots, and is still only 2U.

I put together a couple of configurations on the website and the price for an r805 system with two top bin quad-core processors and 64 GB of RAM seems like a great deal to me. I guess that I'm still thinking about some of the old PowerEdge 8450 8-way servers that I tested with back in the day with a list price of over 50K, which was a good deal at the time.

Todd - Comments




Hyper-V Quick Migration Part III - Downtime no big deal?
4/28/2008 -- Comments

Jeff from the Microsoft Virtualization team posted part III in his continuing series comparing Quick Migration and VMotion. This entry covers planned outages. His point is that most customers plan for downtime anyway, so having some downtime is fine. He also says that in their conversations with existing VMware customers, they still do their maintenance in downtime windows, even though they have VMotion.

I think this is a fair point, but I also think that customers are wanting to get rid of their downtime windows or shrink them. Quick migration helps to shrink it, and VMotion lets you have only uptime - if you want it.

Todd -- Comments




Microsoft VHD Library
4/22/2008 -- Comments

Microsoft has really demonstrated a strong commitment to virtualization in a variety of ways in the last year. I believe that they are putting forth a very strong effort with Hyper-V which will might be the most compelling feature of Windows Server 2008. In addition to this they have begun to provide preconfigured VMs for development, testing, and evaluation for their server products. Their VHD library has grown to include over 15 products including including SQL Server 2008, Visual Studio 2005, Windows Server 2008, and Vista.

SQLBLog.com has a related post on how to overcome some minor issues that sometimes pop up with these VMs, like the mouse disappearing. As virtualization becomes more mainstream, there will be minor problems like these that pop up from time to time. The time savings with being able to very quickly setup a VM to evaluate new software - is worth it.

Todd -- Comments




Hyper-V Quick Migration Part II
4/18/2008 -- Comments

The second post on the Microsoft Virtualzation Team Blog about Quick Migration and VMotion was added a few days ago. It is mostly a discussion about how VMware HA and Quick Migration both provide a failover solution for UNplanned downtime. I agree with Jeff that both do basically the same thing in the event of an unplanned server outage - the VM is moved to another server and restarted.

The difference that he doesn't talk about is that the rules of the failover are different because of the underlying filesystem that is used in each solution. Microsoft Hyper-V and Quick Migration are using the tried and true Microsoft failover-clustering, which uses an NTFS filesystem on the shared storage. As this is not a cluster file system, the shared storage is actually only visible to one of the servers at a time to prevent corruption. VMware ESX server and VMware HA are working with VMs that are on a VMFS file system which is cluster aware - meaning that multiple ESX servers are able to access the files (or VMs in other words) at the same time.

So following a failure of a Hyper-V server, all VMs on the same disk (or LUN) must be recovered on the same server because the LUN or disk can only be used by one server at a time. In the event of a failure of an ESX server, the VMs can be restarted on any ESX server that has access to the LUN. In order to achieve this flexibility with Hyper-V and Quick Migration it would be necessary to have each VM on it's own LUN. This isn't impossible, but could be more complex to setup and manage.

The end result would be same - the VMs would be restarted on another server. Some of the underlying details can make a difference with flexibility in where those VMs end up.

Todd -- Comments





Virtual NIC Performance
4/17/2008 -- Comments

During our regular TechTuesday webchat, a question came up about virtual NIC performance. The topic this week was Running Enterprise Apps on VMware, and one aspect of that is performance. Hywel, who has a successful SQL Server deployment on ESX, asked - why is he only getting 250 mb/s of throughput? I found a VMware blog post and a whitepaper that indicate it is possible to get much higher. Of course in real-world use through-put will be lower, but I would think that you could top 250 mb/s. I believe that the key to getting the best performance form a virtual NIC in VMware is to install the VMtools and use the VMxnet NIC.

Todd -- Comments




A ScreenShot for Geeks
4/14/2008 -- Comments

I will be the first to admit that I haven't always been a fan of using the biggest baddest system you can find for ESX servers, but some things have changed and I do realize there are cases where really big systems make sense. Which brings me around to the newest system that we ordered for the lab - an R900 with four quad-core top bin processors and 128GB of RAM. This arrived in the lab on Thursday morning and I had ESX on it late that afternoon.

When I saw the system in Virtual Center, it really hit home just how much power you can get in a single system these days. This screen shot is something that only a geek would love (16 CPUs and 128GB of RAM!).



I'm thinking of doing some Exchange 2007 testing.... If I can just find enough disks.

Todd -- Comments




Hyper-V Quick Migration Part 1
4/10/2008 -- Comments

Jeff from the Microsoft Windows Server Virtualization team posted yesterday on their team blog the first in a promised 4 part series on Hyper-V HA and Quick Migration and it's differences with VMware's VMotion or live migration. This first post doesn't really get into the differences, but does a good job of explaining why you need an HA for a virtualizaiton solution.

I am really looking forward the other posts to get the full rundown on quick migration. Jeff makes a reference that this series of posts is in response to "buzz" on the internet. I can only guess that part of that buzz is due to things like a recent video posted by David Marshall on vmblog.com showing Hyper-V Quick Migration in action, and discussions in a few places including the RTFM Education blog, blog.scottlowe.org, and the From the VMware Field Blog.

So it will be good to get Microsoft's side of the story.

Todd - Comments




Is it Cool to Use Virtualization?
4/9/2008 -- Comments

These days, it seems like everybody is at least looking at using VMware or Xen or some other virtualization solution. It's the cool thing to do. Clearly.

But what about when you run something like Exchange or SQL Server or Oracle? It seems that almost everybody is cool with virtualization, until you start talking about stuff like this. Then there is a pause. Some decide to push forward, others decide to wait, still others may declare that they would never do it!

There are lots of issues to consider including support, performance, backup, disaster recovery, and even non-technical things like organizational structure and management support. So the answer for everybody isn't the same. The next TechTuesday chat is going to have this as it's discussion point - Running enterprise apps virtualized - to let everybody learn from each other.

Todd - Comments





SQL Server on VMware Server
4/4/2008 -- Comments

I recently ran across this blog entry on Scott's Blog (no relation to Scott Hanson on my team) about a migration of a SQL Server DB to a VM running VMware Server. I have spent only limited time working the the VMware Server (formerly GSX) product and instead have concentrated on ESX. This entry has some interesting info about their experiences with getting SQL Server production DB performing at acceptable levels including a nice "lessons learned" section at the end. For those thinking about going the VMware Server route, then this is a great read.

Todd -- Comments





Running SQL Server in a VM
4/2/2008 -- Comments

I published a new white paper this week on running SQL Server in a VM. The paper focuses on the performance of a large (well 100 GB) version of the DVD Store when running on 64-bit SQL Server 2005. I started this testing just after ESX Server 3.5 was finished and made available, and I believe that it is the first paper with performance numbers of SQL on ESX 3.5 (Please correct me if there are some!). In addition to the paper we had a web chat on Tues on the topic. And I have setup a wiki page to collect SQL on VMware resources and serve as a central place to host threads.

A couple of interesting notes, well at least interesting in a kind of really geeky way:

The first performance study on VMware that Dell published was a paper by Dave Jaffe and I on VMotion performance. We used a 1 GB version of the DVD Store database on SQL Server 2000 as the test VM. So this test really is an update in some ways to that paper. Same basic conclusion regarding VMotion with SQL Server - it is very hard to measure or detect the impact to DB performance of a VMotion.

This study was similar in many ways to the testing that Kong Yang and I did late last year on Exchange 2007. Key difference is that SQL Server is much easier to test! Exchange and LoadGen have extremely time consuming requirements to setup and initialize testing, but the DVD Store on SQL Server can be created and loaded in a much shorter time, and includes cleanup or resetting scripts that are also very fast.

Todd -- Comments




PERC6 Performance Analysis Report
3/28/2008 -- Comments

Our System Performance Analysis lab recently completed a series of tests to evaluate the performance of the newest PowerEdge Expandable RAID Controller (PERC) and published the results in a performance analysis report. The tests with the PERC6 were very through with many RAID types tested - 0, 1, 5, 6, and 10 - on 12 different workload type profiles. Results provide guidance for what PERC6 settings will provide optimal performance for a given workload type.

Additional cool stuff in the report: A good discussion about all of the different RAID types with definitions, and an analysis of the results which recommend when to use which RAID type. The guys that do these tests are storage geeks - and it shows in the report!

Todd -- Comments




Using Simple Password on WS08 Domain Controller
3/24/2008 -- Comments

In the process of getting my new Windows Server 2008 Domain Controller VM setup, I needed to set the password for the new domain's Administrator account to match our lab standard password. This password doesn't meet the default complexity requirements that the Domain Policy establishes. So I had to use Group Policy Management (located in Administrative Tools) to edit the Default Domain Policy. In Computer Configuration > Security Settings > Account Policies > Password Policy, there are several settings that control what passwords are allowed for how long. I disabled the complexity requirements (must have a capital letter, lowercase letter, number, and not be based on a star trek character type of requirements).

I then saved the changes and verified that they had taken effect by viewing the domain policy. I was already logged on as the domain Administrator, so I pressed CTRL-ALT-DEL and selected Change a password.... I typed in the old password (that I had made suitably complex to be able to complete installation) and the new simple password. I received an error message "Unable to update the password. The value provided for the new password does not meet the length, complexity, or history requirements of the domain."

After checking again that the domain policy was in fact changed to allow simple (or non-complex) passwords, I did what any good Windows admin would do - I rebooted. Following reboot it still did not allow me to change passwords. I created a new account - Admin - that way a copy of the original Administrator account and was able to assign it the simple password without a problem. I then logged on as this new Admin user and used Active Directory Users and Computers to reset the Administrator account to the new simple password - with no problem.

So I wasn't able to change it from the CTRL-ALT-DEL (or windows security) Change a password... screen, but I was able to change it by resetting it from another account. I wasn't able to find any other hits via google on this problem and resolution, even after I had figured it out. I'm not sure what this is the way it works, but I did find a way around.

Todd -- Comments




Opps Leads to PSOD and New WS08 Domain Controller VM
3/20/2008 -- Comments

I have a confession to make. I was trying to rush through a setup of VCB server on our SAN late last week and ended up reformatting the wrong LUN. Now this was all in our lab so no matter what gets destroyed - it's not the end of the world. But of all the LUNs, this was probably the one that I really didn't want to get reformatted. It had the Domain Controller for the older of our two Windows Server 2003 Domains in the lab. This DC was also the only DNS for that portion of the lab - so DNS was out which was the really annoying part.

It took me about a half a day of investigation to figure out exactly what had happened because that older domain isn't used as much and a weekend passed before anybody complained. At first I thought that the VMFS partition had gotten corrupted, which turned out to be kinda true. The problem was it was me that corrupted it by formatting it with an NTFS filesystem.

After mourning for a few minutes, I decided that this would be a good opportunity to install my first Windows Server 2008 domain. First I straightened out the LUNs and formatted the correct LUN as NTFS and unassigned the initial LUN away from the windows system. I then used the Add Storage option in Virtual Center for the ESX server that I was using to get the LUN reformatted as VMFS. For some strange reason I was then getting an error when I tried to create my new WS08 DC VM on that LUN. So I tried to create it from another ESX server in the same server farm. I had to do a rescan of the storage adapters, but then the storage showed up and everything seemed to work OK.

I used the WS08 RTM ISO to install the new VM, but got an error on reboot of the VM that the installation was corrupt. I did some investigating and found that several ESX systems thought that they still had VMs running from the original LUN before it was formatted NTFS and then reformatted VMFS. This ended up causing a PSOD (Purple Screen of Death - very cool if you haven't see one yet) on one ESX server when I tried to access one of these VMs. It apparently also caused some corruption in the new VM that I was building.

So I went back and did storage adapter rescans on all ESX servers in the farm and made sure that all VMs that were from the LUN that I deleted were removed from inventory. After this my install of the new DC went great.

I have only had two PSODs while working with ESX, this one was caused by me doing something that you really really shouldn't do with your storage. I learned (or maybe learned again) that you should always take your time when you are going to do something like format and make sure you have the right disk!

Todd -- Comments




VMware Blog Entry on Exchange
3/7/2008 -- Comments

DellTechCenter's resources on Exchange on VMware were included in a post on VMware's blog. The entry is about the recent testing VMware did to get 16,000 Exchange 2007 users on a single server by using ESX Server. The entry then goes on to cite other Exchange on VMware resources and includes our very own TechCenter resources:

Exchange and VMware at the Dell Enterprise Technology Center wiki

• Virtualizing Exchange Server 2007 on ESX 3 - Whitepaper
• VMotion and HA with Exchange 2007 on ESX 3 - Whitepaper
• Virtualizing Exchange 2007: The Final Frontier - Presentation
• Exchange Server 2003 Performance on ESX 3 - Whitepaper

They have lots of other great info on Exchange on VMware included in the post. It is recommended reading.

Todd -- Comments




VMotion of Exchange Mailboxes on ESX Server
3/5/2008 -- Comments

I saw this blog entry on savagenomands that wondered about VMotion with large Exchange VMs:

"Even with all that horse power, they didn’t talk about network traffic running all exchange 2007 roles on the same box. I wonder how long one of these boxes takes to vmotion. Also I’d like to know the details on how they setup the luns and if they used vmdk files "

I actually did some similar testing with 2000 user Exchange VMs and measured the time for VMotion to complete as well as its impact on the users. The answer - about 6 and half minutes to VMotion a 2000 user VM while under stress (At least with the setup that I had. Your mileage will vary depending on your exact configuration). See the whitepaper on the VMware and Exchange page to get the complete details.

Todd -- Comments




Dell EqualLogic Blog
2/29/2008 -- Comments

I had the chance yesterday to meet Marc Farley who is a new to Dell via EqualLogic. He is running a blog on the Equallogic site. Marc participated in the EqualLogic webchat we did on DellTechCenter a couple of weeks ago as a subject matter expert. So I had kinda met him before, but this was the first in-person meeting.

We had a great discussion about the things they did at EqualLogic to connect with their customers and we talked about some ideas for continuing that now that EqualLogic is part of Dell. We are currently in the process of getting some of the new EqualLogic arrays into the TechCenter lab. So let us know what kinds of things you would like to see / hear about.

Todd -- Comments




Firewall VMs and Virtual Switch Security
2/27/2008 -- Comments

On the Tech Tues chat yesterday a question came up about setting up a firewall VM by connecting one of the NIC ports on the ESX server to external Internet. The question was - Is this a good idea? Is it secure? What is the best practice?

I did a little research this morning and found a white paper from VMware that mentions the exact scenario of having one VM connected externally and acting as a firewall. On page six of VMware Networking Concepts (located at http://www.vmware.com/files/pdf/virtual_networking_concepts.pdf ) there is a diagram and discussion about it.

There is another VMware doc titled ESX 3 Best Practices Guide that I found attached to a VMTN discussion ( http://communities.vmware.com/message/861839#861839) that covers networking best practices. It also has the same recommendation that using virtual switches is very secure and allows for things like firewalls to be setup in a VM.

Todd -- Comments





New Storage VMotion Demo
2/21/2008 -- Comments

I had a chance to play around with the new Storage VMotion feature of VMware ESX Server 3.5 / Virtual Center 2.5 and found it to be easy - once you get the command line tools in place. You have to have the Virtual Infrastructure Remote CLI package in place to be able to execute the svmotion command.

I was able to move the SQL Server VM from one LUN to another while under stress using Storage VMotion. I think that it's kinda cool to see in action - so I captured it in a quick video.

Yes - That's my voice on the demo - so be kind with your comments!

Todd -- Comments




Virtualizing Big Databases
2/20/2008 -- Comments

I've been doing quite a bit of work over the last few years to provide some data as to how things like SQL Server databases and Exchange mailbox servers perform inside a VM. All in all the story has turned out to be pretty good. Sure, running in a VM does have a certain performance overhead or penalty, but when most servers are running at 20% utilization or lower - this turns out to not be a problem.

Specifically I have been running some SQL Server 2005 tests, which I am wrapping up now, in the last few weeks. On a conference call today where we were discussing the results a question came up that I thought was pretty good -

What "size" of SQL Server database do most people run?

Of course this is an impossible question to answer, but of course I came up with an answer anyway! In terms of SQL Server databases that are running in VMs - I think that so far most people have only migrated "smallish" databases. Ones that don't have extremely high transaction rates. I do know of a few cases where more performance intensive databases have been virtualized, but these are the exception today. I think that in the future more of these high performance DBs will also be virtualized.

I think that many IT shops are looking at virtualization and think that it would be really cool to move some of their "bigger" stuff into VMs. To take advantage of a better way to manage things, but they are waiting to see how everything plays out before they begin to virtualize big apps like SQL Server, Exchange, Oracle, etc.

Todd -- Comments




Virtualization Frontier Archives

January 2008
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