Uncategorized | CrashLoopBackoff

Ask Good Questions

This happened a long time ago. I arrived at a customer site to install View Desktop Manager (may have been version 2). This was before any cool VDI sizing tools like Liquidware Labs. I am installing ESX and VDM I casually ask, “What apps will you be running on this install?” The answer was, “Oh, web apps like youtube, flash and some shockwave stuff.” I thought “ah dang” in my best Mater voice. This was a case of two different organizations thinking someone else had gathered the proper information. Important details sometimes fall through the cracks. Since that day, I try to at least uncover most of this stuff before I show up on site.

Even though we have great assessment tools now, remember to ask some questions and get to know what is your customers end goal.

Things I learned that day. As related to VDI.

1. Know what your client is doing, “What apps are you going to use?”

2. Know where your client wants to do that thing from, “So, what kind of connection do you have to that remote office with 100+ users?”

This is not the full list of questions I would ask, just some I learned along the way.

VMware View – User Profile Options

All the technology and gadgets for managing desktops are worthless if your users complain about their experience with the desktop. Something I learned administering Citrix Presentation Server. Differing methods exist to keep the technical presentation of the desktop usable, for example the mouse being in sync and the right pixels show the right colors. What is also included in the user experience is a consistent environment where their personal data and settings are where they should be. Here are a few methods for managing those bits when using VMware View.

Mandatory Profiles
This profile is kept on the a central file share. The profile is copied to the machine on login, when the user logs out the changes are not kept. Great way to keep a consistent profile on kiosk type and data entry desktops. Where customization is not needed and most likely not wanted mandatory profiles are worth exploring. Main change is you set up the profile just like you want it then rename the NTUSER.dat to NTUSER.man. A lot exists on the internet about setting up man profiles.

Local Profiles
If you go through life never changing a thing in your Windows environment, you are using a Local Profile. Not to say you don’t change settings, save files or customize your background. You just have Windows running as the default. This is an option I will usually discourage because it is hard to backup data that is often kept in the local profile. VMware View will redirect user data to a User Data Disk (or whatever it is called today) on Persistent Desktop Pools. This is a good way to get the data on another VMDK. This introduces problems when looking at data recovery. There is solutions, but just something you will need to remember to look into.

Roaming Profiles
Roaming profiles is a great way to redirect current profiles to a central location. In theory this works great. In a View environment you can keep a local copy on a users desktop profile and the changes are copied back and forth. I have often seen this work just great. Then from time to time, the profile will become corrupt, many times it does not unload correctly when users disconnect, or log out. Then you may have to pick through folders trying to find their “My Documents”. This is why I would suggest using this with Group Policy and Folder redirection which I will cover next.

Redirecting Folders
You may end up using a folder redirection group policy. This will move folders like the Desktop and My Documents for a user to a file server. This slims down the roaming profile as those locations are redirected to another location outside of the profile. This data is not copied from the machine to the server over and over. More information here.

Other Options
Immidio Flex Profiles
I really liked this option it was a way to combine mandatory profiles and a Roaming profile. This program would run some scripts on logon and log off to save files and settings. A really great paper on how to use it can be found here. Just like any great program that takes a new way to solve an annoying old problem, this is now not free.

RTO Virtual Profiles
I have never implemented this solution before. I have used it as part of a few training labs. I liked the feel. Now that VMware has purchased this software from RTO, the website redirects to a transition page. So I am looking for a way to test it in the lab, hoping the next set of bits of View includes RTO. Check this FAQ out for more information.

Maybe once it is built into View this will no longer be a serious issue. Profiles will be one of those things we tell stories to young padawan VM admins about, “We used to have to fight profiles, they were big and slow, and sometimes they would disappear!” Until that day…

Random Half Thoughts While Driving

So I often have epiphany teasers while driving long distances or stuck in traffic. I call them teasers because they are never fully developed ideas and often disappear into thoughts about passing cars, or yelling at the person on their cell phone going 15 MPH taking up 2 lanes.

Here is some I was able to save today (VMware related):

1. What if I DID want an HA cluster to be split in two different locations, Why?
2. Why must we over-subscribe iSCSI vmkernel ports to make the best use of the 1gbe phyical nics. Is it a just the software iSCSI in vSphere? Is just something that happens with IP storage? I should test that sometime…
3. If I had 10 GB nics I wouldn’t use them on Service Console or Vmotion that would be a waste. No wait, VMotion ports could use it to speed up your VMotions.
4. Why do people use VLAN 1 for their production servers? Didnt’ their Momma teach em?
5. People shouldn’t fear using extents, they are not that bad. No, maybe they are. Nah, I bet they are fine, how often does just 1 lun go down. What are the chances of it being the first lun in your extent? Ok maybe it happens a bunch. I am too scared to try it today.

VMware View and Xsigo

*Disclaimer – I work for a Xsigo and VMware partner.

I was in the VMware View Design and Best practices class a couple weeks ago. Much of the class is built on the VMware View Reference Architecture. The picture below is from that PDF.

It really struck me how many IO connections (Network or Storage) it would take to run this POD. Minimum (in my opinion) would be 6 cables per host with ten 8 host clusters that is 480 cables! Let’s say that 160 of those are 4 gb Fiberchannel and the other 320 are 1 gb ethernet. The is 640 gb for storage and 320 for network.

Xsigo currently uses 20 gb infiniband and best practice would be to use 2 cards per server. The same 80 servers in the above cluster would have 3200 gb of bandwidth available. Add in the flexibility and ease of management you get using virtual IO. The cost savings in the number director class fiber switches and datacenter switches you no longer need and the ROI I would think the pays for the Xsigo Directors. I don’t deal with pricing so this is pure contemplation. So I will stick with the technical benefits. Being in the datacenter I like any solution that makes provisioning servers easier, takes less cabling, and gives me unbelievable bandwidth.

So just in the way VMware changed the way we think about the datacenter. Virtual IO will once again change how we deal with our deployments.

iSCSI Connections on EqualLogic PS Series

Equallogic PS Series Design Considerations

VMware vSphere introduces support for multipathing for iSCSI. Equallogic released a recommended configuration for using MPIO with iSCSI. I have a few observations after working with MPIO and iSCSI. The main lesson is know the capabilities of the storage before you go trying to see how man paths you can have with active IO.

EqualLogic defines a host connection as 1 iSCSI path to a volume. At VMware Partner Exchange 2010 I was told by a Dell guy, “Yeah, gotta read those release notes!”
EqualLogic limits the number of hosts in the to 128 per pool or 256 per group connections in the 4000 series (see table 1 for full breakdown) and to 512/2048 per pool/group connections in the 6000 series arrays.
The EqualLogic MPIO recommendation mentioned above can consume many connections with just a few vSphere hosts.

I was under the false impression that by “hosts” we were talking about physical connections to the array. Especially since the datasheet says “Hosts Accessing PS series Group”. It actually means iSCSI connections to a volume. Therefore if you have 1 host with 128 volumes singly connected via 1 iSCSI path each, you are already at your limit (on the PS4000).

An example of how fast vSphere iSCSI MPIO (Round Robin) can consume available connections can be seen this this scenario. Five vSphere hosts with 2 network cards each on the iSCSI network. If we follow the whitepaper above we will create 4 vmkernel ports per host. Each vmkernel creates an additional connection per volume. Therefore if we have 10 300 GB volumes for datastores we already have 200 iSCSI connections to our Equallogic array. Really no problem for the 6000 series but the 4000 will start to drop connections. I have not even added the connections created by the vStorage API/VCB capable backup server. So here is a formula*:

N – number of hosts

V – number of vmkernel ports

T – number of targeted volumes

B – number of connections from the backup server

C – number of connections

(N * V * T) + B = C

Equallogic PS Series Array	Connections (pool/group)
4000E	128/256
4000X	128/256
4000XV	128/256
6000E	512/2048
6000S	512/2048
6000X	512/2048
6000XV	512/2048
6010,6500,6510 Series	512/2048

Use multiple pools within the group in order to avoid dropped iSCSI connections and provide scalability. This reduces the number of spindles you are hitting with your IO. Using care to know the capacity of the array will help avoid big problems down the road.

*I have seen the connections actually be higher and I can only figure this is because the way EqualLogic does iSCSI redirection.

Five Things you should know about VMware Certification – thanks @rickvanover

Tonight I was sitting with my Mac Book Pro, wife and kids all in bed, perfect blogging time. Except no idea what I wanted to write. After a burst of twitter encouragement from @rickvanover here we go:

Five things you should know about VMware Certs:

1. If you work for a VMware partner, start with the VSP/VTSP Certifications. They require a lot less initial investment and give you the start into VMware products. Partners only.

2. You can take the “Install and Configure” or “Design Secure and Analyze” or the “Fast Track” (which is some kind of combo of the previous 2) then study and take the VCP. The VMware Certified Professional is the standard in Virtualization industry and has personally opened many doors for me professionally. VMware Partners NEED them, but it is quite an investment. The class is far from free and the test isn’t cheap. Something to know though, if you go to VMworld the tests are discounted. So everyone at VMworld take advantage! Save a few bucks.

3. As good as the VCP is, there is still a demand for VMware knowledge more advanced than the base cert. I lost my job last year, while job hunting I saw listings asking for VCDX certified people. At the time no VCDX’s were publically known. It just shows the demand for proof of advanced knowledge in VMware and a possible dilution of the VCP due to brain dumping.

4. Testing experience is fairly standard technical testing. Although I wish it was all lab practical rather than memorization. Multiple choice type questions are the majority of the questions. My best test taking tip is to actually know how to Install and Manage Virtual Infrastructure. You can run it all in VMware Workstation 7, so there is no excuse to just memorize answers. I say that but you will have to memorize max and minimums and other facts in order to pass the VCP.

5. Check what is on the blue print on the VMware Certification website, this website is the final word on what is on the test.

Bonus: Use the communities/blogs/twitter to find information and answers. Don’t just post “Hey what is on the exam?”. Ask questions about technical topics, then make sure you could articulate the concept to someone else. I find if I understand enough to be able to teach it to someone else then I really am starting to learn things.

Bonus #2: Be willing to be always learning. If you already know everything you probably don’t need the certification.

*No clue who the original artist is of that picture. It is awesome, so if you know who to credit let me know.

New VMware KB – zeroedthick or eagerzeroedthick

Due to the performance hit while zeroing mentioned in the Thin Provisioning Performance white paper this article in the VMware knowledge base could be of some good use.

I would suggest using eagerzeroedthick for any high IO tier 1 type of Virtual Machine. This can be done when creating the VMDK from the GUI by selecting the “Support Clustering Features such as Fault Tolerance” check box.

So go out and check your VMDK’s.

Top 25 – Vote Now

Well time to get on over to Eric Siebert’s vSphere-land and vote for the top 25 VMware Blogs. The goal this year is to have someone besides my Mom and myself vote for me. So if you happen to like the content of this blog please vote for me. Now some recap of recent posts to remind you why a vote for 2vcps is a vote for vAwesomeness.

Remember the what not to tweet list? Always fun.
What about the time I ranted some nonsense from VMworld? Here. and here.
Who could forget the time I said some stuff about VMware?

I trust equiped with this information you will now be able to place 2vcps in your list of votes.

All kidding aside, I think it is just cool to be on the ballot. 🙂

Recap of 2009

Thank you to everyone out there that gave any attention to this little blog. I tried to supply new information where I could and also document my journey trying to improve at the esxcfg- commands. In 2009 the traffic increased from less than 100 visits in a week to approaching 500 in a week. That is a slow hour for some of the best vm bloggers (Yellow-Bricks, Scott Lowe) but I am not trying to replace them.

In March I was layed off. I spent 2 months full time looking for work. The VMware community really stepped up. Special thanks go out to a few people that tried to help out or checked in with how the search was going: @jasemccarty @maishk @jasonboche and many others. By the end of April I started a new position as a Virtualization Infrastructure Engineer at Veristor Systems. This job required moving the family from Memphis, Tennessee to Atlanta, Georgia. All the fun of a new job, house hunting and moving to a completely new city. We closed on our new house just a few days after VMworld 2009. My first trip to VMworld was amazing but I would suggest not buying a house while you are in and out of conferences, labs and seminars. Lots of details to fix, I will be happy if this is not the case ever again.

After such a busy year it was only the beginning of September. The rest of the year was filled with VMware Installation projects and VMware health checks. I was all over the Southeast US. Maybe I can come visit some of you in 2010?

Technical/VM/Blogging Goals for 2010:

Continually improve the quality of content going to this blog.
Schedule, take and pass the VCDX exams.
Improve my overall storage knowledge.
Renew my expired CCNA (bad move letting this lapse in 2009)

2009 was such a big year personally. I hope and pray for a little more stability in 2010 but I also love the excitement of new challenges, but the VCDX should be enough. 🙂

Also, I scheduled a Merry Christmas post, but for some reason I didn’t do what I thought I did. So a late Merry Christmas to all of you out there.

Storage Design and VDI

Recently I have spent time re-thinking certain configuration scenarios and asking myself, “Why?” If there is something I do day to day during installs is this still true when it comes to vSphere? or will it still be true when it comes to future versions.
Lately I have questioned how I deploy LUNs/volumes/datastores. I usually deploy multiple moderate size datastores. In my opinion this was always the best way to fit in MOST situations. I also will create datastores based on need afterward. So will create some general use datastores then add a bigger or smaller store based on performance/storage needs. After all the research I have done and asking questions on twitter* I still think this is a good plan in most situations.
I went over a VMworld.com session TA3220 – VMware vStorage VMFS-3 Architectural Advances since ESX 3.0 and read this paper:
http://www.vmware.com/resources/techresources/1059
I also went over some blog posts at Yellow-Bricks.com and Virtualgeek.

An idea occurred to me when it comes to using extents in VMFS, SCSI Reservations/Locks, and VDI “Boot Storms”. First some things a picked up.
1. Extents are not “spill and fill” VMFS places VM files across all the LUNs. Not quite what I would call load balancing, since it does not take IO load into account when placing files. So in situations where all the VM’s have similar loads this won’t be a problem.
2. Only the first LUN in a VMFS span gets locked by “storage and VMFS Administrative tasks” (Scalable Storage Performance pg 9). Not sure if this implies all locks.

Booting 100’s of VM’s for VMware View will cause locking and even though vSphere is much better when it comes to how quickly this process takes. There is still an impact. So I am beginning to think of a disk layout to ease administration for VDI, and possibly lay the groundwork for improved performance. Here is my theory:

Create four LUNs with 200GB each. Use VMFS to extents to group them together. Resulting in an 800 GB datastore with 4 disk queues and only 1 LUN that locks during administrative tasks.

Give this datastore to VMware View and let it have at it. Since the IO load for each VM is mostly the same, and really at the highest during boot other tasks performed on the LUN after the initial boot storm will have even less impact. So we can let desktops get destroyed and rebuilt/cloned all day with only locking that first LUN. This part I still need to confirm in the LAB.

What I have seen in the lab is with same sized clones the data on disk was spread pretty evenly across the LUNs.

Any other ideas? Please leave a comment. Maybe I am way off base.

*(thanks to @lamw @jasonboche and @sakacc for discussing or answering my tweets)