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