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vSphere 5 – Storage pt.3 LUN Sizing – Why it matters..

Well, I guess I am on a roll this week. I feel like a lot of my themes have been around storage and VMware this week. I don’t think that is a bad thing but I am seeing some gaps out there as far as considerations and recommendations. My only point in this post is to share my thoughts for you and what you should consider when facing this after your vSphere 5 upgrade or after you install it. I have to wonder just how many enterprises out there have seriously pushed the envelope of LUN sizing in VMware. One has to think; “If you are carving up large LUNS does that mean your scaling up?”. There are so many implications one should consider when designing your storage. One of the more critical pieces is I/Ops and the cluster size and what your target workload is. With bigger LUNS this is something you have to consider and I do think it is common knowledge for the most part.

There are so many things one should consider when deciding on a LUN Size for vSphere 5. I sincerely believe VMware is putting us all in a situation of scaling up sometimes. With the limitations of SDRS and Fast Provisioning it has really got my mind thinking. It’s going to be hard to justify a design scenario of a 16 node “used to be” cluster when you are trying to make a call on if you really want to use some of these other features. Again, you have heard me says this before but I will say it again; it seems more and more that VMware is making a huge target of this to Small to Medium sized businesses but offering some features larger sized companies (with much bigger clusters) now have to invest even more time in reviewing their current designs and standards – Hey, that could be a good thing 🙂 . Standards to me are a huge factor for any organization. That part seems to take the longest to define and some cases even longer to get other teams to agree to. I don’t think VMware thought about some of those implications but I am sure they did their homework and knew just were a lot of this was going to land…

With that being said I will stop my rambling on about these things and get to the heart of the matter or better yet heart of the storage.

So, After performing an upgrade I have been wondering what LUN size would work best. I believe I have some pretty tough storage and a solid platform (CISCO UCS) so we can handle some I/Ops. I wanted to share some numbers with you that I found was very VERY interesting. I have begun to entertain the notion of utilizing Thin Provisioning even further. However, we are all aware that VMware still has an issue with UNMAP command which I have pointed out in previous blogs (here). However being that I have been put between a rock and hard place I believe update 1 to vSphere 5 at least addressed 1/2 of my concern of it. The other 1/2 that didn’t was the fact that now I have to defer to a manual process that involves an outage to reclaim that Thin Provisioned space… I guess that is a problem I can live it with given the way we use our storage today. It doesn’t cause us to much of a pain, but it is a pain none the less.

Anyways, so here is my homework on LUN sizing and how to get your numbers (Estimates):
(Note: This is completely hypothetical and not related to any specific company or customer; this will also include Thin Provisioning and Thick)

  • Factor an Average IOps per LUN (if you can from your storage vendor or from vCenter or an ESXi host)

    Take the IOps per all production LUNS and divide it by the number of datastores

    Total # IOps / # of Datastores

  • Gather the average numbers of virtual machines per datastore

    Total # VM’s / # of Datastores

    Try to use Real World production virtual machines

  • Decide on the LUN Size and use your current baseline as a multiplication factor from your current.

    So if you want to use 10TB Datastores and you are using 2TB datastores you can take whatever numbers and

    10TB / 2TB = 5 (this is you multiplication factor for IOPs and VM:Datastore Ratio)

So now let’s use an example to put this to practical use… and remember to factor in free space for maintenance I always keep it at 10% free.

Let’s say we have a customer with the following numbers before:

16 VM’s per Datastore

1200 I/Ops Average per Datastore (we will have to account for peak to)

2TB Datastore LUNS

Now for the math (Lets say the customer is moving to 10TB LUNS so this would be a factor of 5):

16 x 5 = 80 VM’s per Datastore (Thick Provisioned)

120 x 5 = 600 IOps per Datastore…

Not bad at all, but now let’s seriously take a look at thin provisioning which is QUITE different on numbers. Let’s say we check our storage software and it tells us on average a 2TB LUN only really uses 500 GB of space for the 16 VM’s per Datastore. Lets go ahead and factor some room in here (10% for alerting and maintenance purposes this time around). You can also download RVTools to get a glimpse of actual VM usage versus provisioned for some thin numbers.

First off:

16 VM per 500GB so that times 4 for the 2TB LUN; Makes 64 Thin VMs per 2TB Datastore.

Times that by the new LUN size 9TB / by 2TB = 4.5 (minus 10% for reserved for alerting purposes and Maintenance; this could also be considered conservative)

64 x 4.5 = 288 Average VM Per 10TB Datastore (and that 1 TB reserved too!)

We aren’t done yet; here comes the IOPs and lets use 1500 IOPs. Since we times the VM’s by a factor of 4 we want to do this for the average of IOPs as well:

1500 x 4 = 6000 per 2TB LUN; Using thin provisioning on VMs

600 x 4.5 = 2700 IOps per LUN.

So this leave use with the following numbers for thick and thin:

VM to 10TB Datastore ratios:

80 Thick

288 Thin

IOps to 10TB Datastore ratios:

6000/IOps Thick Provisioning

2700/IOps Thin Provisioning

So, I hope this brings to light some things you will have to think about when choosing a LUN size. Also note that this is probably more of a service provider type of scenario as we all know most may use a single 64TB LUN though I am not sure I would recommend that. It all comes down to use-case and how it can be applied. So this also begs to question what’s the point of some of those other features if you leverage Thin Provisioning. Here are some closing thoughts and things I would recommend:

  • Consider Peak loads for your design; the maximum IOps you may be looking for in some cases
  • Get an average/max per VM datastore ratio (locate your biggest Thin VM)
  • Consider tiered storage and how it could be better utilized
  • Administration and Management overhead; essentially the larger the LUN the less over all provisioning time and so on.
  • VAAI capable array for those Thin benefits (running that reclaim UNMAP script..)
  • Benchmark, Test using some other tools on that bigger LUN to ensure stability at higher IOps
  • Lastly the storage array benchmarks and overall design/implementation
  • The more VM you can scale on a LUN can affect your cluster design; You may not want to enable your customers to scale that much
  • Alerting considerations and how you will manage it efficiently to not be counterproductive.
  • Consider other things like SDRS (fast provisioning gets ridiculous with Thin Provisioning)
  • Storage latency and things like Queues can be a pain point.

I hope this helps some of those out there that have been wondering about some of this stuff. The LUN size for me dramatically affect my cluster design and what I am looking to achieve. You also want to load test your array or at least get some proven specs on the array. I currently work with HDS VSP arrays and these things can handle anything you can throw at them. They are able to add any type of additional capacity you need rather it be Capacity, IOps, Processing or what not you can easily scale it out or up. Please share your thoughts on this as well. Here are some great references:

http://www.yellow-bricks.com/2011/07/29/vmfs-5-lun-sizing/
http://serverfault.com/questions/346436/vmware-vmfs5-and-lun-sizing-multiple-smaller-datastores-or-1-big-datastore
http://communities.vmware.com/thread/334553
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2014849 

Note: these numbers are hypothetical but its all in the numbers.

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Update vSphere 5 – My two cents err problems

What’s the deal man?

Well to be honest I have ran into two very specific issues and what I want to iterate is how crucial it is to review updates before just deploying a normal vSphere 5 implementation. First off, I want to say that in the middle of my experience with performing the upgrade to vSphere 5 the release of Update 1 occurred. So with that being said comes the dilemma. Coordinating the update process and procedure should always be critical. You should also do your due diligence and review the updates along with bugs. I have to honestly give credit to the VMware Community which has definitely allowed me to identify problems before hand and how to avoid and workaround those. Now on to my issues.

Issue Number 1:Broken sVmotion (Storage Migration)

Well, this one was obvious but being the optimist I am didn’t think I would run into this little issue. However it appears to be a ESXi special feature for vSphere 5! I would highly recommend reviewing the following issues if you are having problems performing storage vMotions on vSphere 5/vCloud 1.5. I believe it is actually an issue with the ESXi hypervisor because prior to Update 1 there was a patch you could install on your ESXi box. Please see the following references for resolution:
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2012122

FIX? > Install UPDATE 1 or ESXi Patch 2

Issue Number 2: vCenter Network Alarm Feature!

So, key words to stress in this issue is probably one that makes many CRINGE. Test and Prod should always be the SAME > We all know how important that is but SERIOUSLY how many of us actually MIRROR everything even the alarms? This is more of an issue with standards and procedures then anything… again I am reminded of the 9 parts planning and 1 part implementing or the “Your poor planning doesn’t account for an emergency on my part”.

If the following statement doesn’t tell you what happened then this KB most certainly can.. 🙂
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2007231

FIX? > Yeah just the read the kb its quite ridiculous… oh wait just install update 1?

So, I am writing this tell you that I would recommend applying or using the in place upgrade for vSphere 5 Upate 1. Oh, and just so you know I warned it still doesn’t support the following build number:

NOTE: I would highly recommend to updating from vanilla 4.1 to avoid the special VMware feature of PSOD.

Last but not least I equally thought it would be important to highlight a video that we can all share and relate to when facing unexpected results…. It’s not exactly the same but I can definitely relate to the frustrations..

Enjoy!

vSphere 5 – Storage pt.2 vCloud and Vsphere Migrations

The point..

So on my last post I covered some things to think on when looking at the new VMFS-5 partitions. Obviously the point in moving to the new VMFS would be to gain all the benefits as explained in that previous post. One thing you will see in this post are just the types of migrations. I also want to highlight that I shared some resources on the bottom for those of you who may want to review some deeper highlights. Obviously there isn’t a ton of documentation out there highlighting this nor the special *features* for vSphere 5 (sVmotion issues??) that you may run into. So let hope I do this yet further justice. On to the blog!

Adding VMFS-5 to the vCloud

  1. Log in to vSphere and ensure you have a new LUN provisioned (covered above in how to:)
  2. Log into vCloud Director Web Interface and you must be an administrator.
  3. Click “System” tab and click on Provider VDC. Right click a PVDC and select “Open”
  4. After opening the PVDC select the Datastores Tab and then click the +/- button to add/remove datastores

  1. Browse through the datastores by clicking the > button or by searching in the top right. When you have located your datastore highlight it and then click the button then click “OK”. Disregard the warning.


(Note: the yellow highlights are ways you can search and browse through datastores. This is very handy when there are many to look through)


(Note: Highlight in yellow shows the datastore added successfully. This is a 20TB Datastore)

You will now see the datastore in the datastore summary tab for that PVDC

Migrating Virtual Machines for vCloud Director to the “new” VMFS-5 LUN.

  1. Make sure the vApp is NOT a linked clone. If it is a linked clone defer to the references below.
  2. Ensure the Datastore you want to Storage Motion the Virtual Machine to is also provisioned to the Org VDC. Do this by opening the Org vDC and selecting the “Datastores” Tab.

    Note: you can see both datastores are attached to this VDC with the organization known as App1

  3. You could then log-in to vSphere client with the following noted vCenter and perform a storage vMotion. Another way of doing a Storage vMotion could be by using William Lam’s script he wrote as well. (see references below)
  4. If you need to perform the sVmotion defer to the following method below.

NOTE: I would highly recommend that you roll out update 1 to all vCloud components. This addresses a few major fixes that will allow for operations to run more smoothly. More importantly, the only way to sVmotion vCloud VMs is to turn them off. This is a pretty common issue with vanilla vsphere 5/vcloud 1.5 roll outs. I also experienced this problem. For more information please see references at the bottom.

Migrate a Virtual Machine with Storage VMotion in vSphere

Use migration with Storage VMotion to relocate a virtual machine’s configuration file and virtual disks while the virtual machine is powered on. You cannot change the virtual machine’s execution host during a migration with Storage VMotion. (Note: that if VM is managed by vCloud and not at 1.5 update 1 you will need to possibly power off the virtual machine to perform the svmotion. If the virtual machine is a fast provisioned vm (linked clone) then you will need to perform the sVmotion through an API.

Procedure

  • Ensure you are not moving vCloud vApp if you are please follow the above process first.
  • Display the virtual machine you want to migrate in the inventory.
  • Right-click on the virtual machine, and select Migrate from the pop-up menu.
  • Select Change datastore and click Next.
  • Select a resource pool (the same) and click Next.
  • Select the destination datastore:
    To move the virtual machine configuration files and virtual disks to a single destination, select the datastore and click Next.
    To select individual destinations for the configuration file and each virtual disk, click Advanced. In the Datastore column, select a destination for the configuration file and each virtual disk, and click Next.
  • Select a disk format and click Next:
  • Option Description
    Same as Source Use the format of the original virtual disk.
    If you select this option for an RDM disk in either physical or virtual
    compatibility mode, only the mapping file is migrated.
    Thin provisioned Use the thin format to save storage space. The thin virtual disk uses just as
    much storage space as it needs for its initial operations. When the virtual disk
    requires more space, it can grow in size up to its maximum allocated capacity.
    This option is not available for RDMs in physical compatibility mode. If you
    select this option for a virtual compatibility mode RDM, the RDM is
    converted to a virtual disk. RDMs converted to virtual disks cannot be
    converted back to RDMs.

    Thick Allocate a fixed amount of hard disk space to the virtual disk. The virtual
    disk in the thick format does not change its size and from the beginning
    occupies the entire datastore space provisioned to it.
    This option is not available for RDMs in physical compatibility mode. If you
    select this option for a virtual compatibility mode RDM, the RDM is
    converted to a virtual disk. RDMs converted to virtual disks cannot be
    converted back to RDMs.

    NOTE: Disks are converted from thin to thick format or thick to thin format only when they are copied from one
    datastore to another. If you choose to leave a disk in its original location, the disk format is not converted, regardless of the selection made here.

  • Review the page and click Finish.
  • A task is created that begins the virtual machine migration process.

References:

Linked Clones:
http://www.virtuallyghetto.com/2012/04/scripts-to-extract-vcloud-director.html
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1014249

Storage Motion Issue:
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2012122

How To’s sVmotion CLI/VCO style:
http://www.virtuallyghetto.com/2012/02/performing-storage-vmotion-in-vcloud.html
http://www.virtuallyghetto.com/2012/02/performing-storage-vmotion-in-vcloud_19.html
http://geekafterfive.com/2012/03/06/vcloud-powercli-svmotion/
http://geekafterfive.com/tag/vcloud/
http://pubs.vmware.com/vsphere-50/topic/com.vmware.ICbase/PDF/vsphere-esxi-vcenter-server-501-virtual-machine-admin-guide.pdf

Storage Considerations for vCloud:
http://www.vmware.com/files/pdf/techpaper/VMW_10Q3_WP_vCloud_Director_Storage.pdf

VMware vSphere Labs – Infrastructure – Setting Up Active Directory on Windows 2008 R2

This Tutorial runs through a quick overview of installing Active Directory 2008 R2 on a Windows Virtual Machines running in VMware Workstation 8. It has a Video and general instructions to help you out. Enjoy!

  1. Deploy from the template
  2. Configure NICS Static
  3. Disable Extra NIC
  4. Gateway and DNS are the Gateway list in “Virtual machine Editor”
  5. Keep DNS as the secondary DNS of the Domain Controller
  6. Rename machine to appropriate Computer Name to reflect your Domain Controller (sysprep gives silly names)
  7. Reboot
  8. Add Role from server manager
  9. Select Active Directory Domain Services
  10. Yes, Install the .Net Stuff….
  11. Run DCPRomo.exe from powershell or within the server manager under AD role
  12. Install DNS (if not you must be doing something a bit more advanced :))
  13. Reboot and validate you can log into AD with a Domain Account.
  14. Join another Virtual Machine to the Domain

VMware vSphere Labs – Foundations – The Template on Workstation 7 and 8 – Windows 2008 R2

This videos covers the template we will be setting up for deploying windows server 2008 r2 from. On this template we will be installing Active Directory, DNS, vCenter Server, and a lot more stuff. At the bottom of the blog will be references for ensuring your template is supremely prepped for space and performance!

Here are both the videos one for doing it:
VMware workstation 7:

On this video I made a few mistakes… but this wouldn’t be VirtualNoob if I didn’t make a few of those.
VMware workstation 8:

Really great resource:

http://www.happysysadm.com/2010/11/vmware-windows-2008-r2-template.html

***Disclaimer: The thoughts and views expressed on VirtualNoob.wordpress.com and Chad King in no way reflect the views or thoughts of his employer or any other views of a company. These are his personal opinions which are formed on his own. Also, products improve over time and some things maybe out of date. Please feel free to contact us and request an update and we will be happy to assist. Thanks!~

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