How to determine your vRAM footprint in vCenter

 Memory, Tips and Tricks  4 Responses »
Jul 202011
 

Unless you’ve been under a rock this past week you have probably heard about the licensing changes that VMware has delivered with vSphere 5.0.  Many of my customers have reacted negatively to the new licensing saying that they won’t fit into the new model.  When I asked my customers what their vRAM footprint was, most customers could not begin to guess what they were using.  Here’s how you can tell from vCenter with a quick export into Excel and a few formula tweaks:

Go into your vCenter (if you have more than one, you will need to do this for each.)  Go into the “Hosts and Clusters” view.  On the left pane, select the vCenter Server itself.  On the right pane, select the “Virtual Machines” tab.  You can optionally click the “State” field title to sort by state.  You may also click the host field to sort VMs by the host names (I would recommend this if you have multiple clusters with multiple editions of ESXi).  You can then right-click the virtual machine titles and add the field for “Memory Size” as shown below.  Right-click right on the word “State” in the title of the column.

Once the Memory field has been added (it will probably be far on the right), drag the filed so it’s just to the right of the “State” field.  Now go to the “File” Menu at the top of the vSphere client and select “File” then “Export” and then “Export List”.  Export the file selecting “Excel Workbook” as the file type.  Once exported, open the list in Excel.  In Excel, add a column to the right of the memory column like so:

Edit Cell D2 and put in this formula:   =IF(B2=”Powered On”,VALUE(LEFT(C2,(LEN(C2)-3))),0)

Copy this formula down the entire column.  This checks to see if the VM state is powered on (you do not draw from your vRAM license if it is not).  It then removes the “MB” and converts the value to a numeric so you can sum them up.

Scroll down to the last row and edit the cell in the next empty row in the memory column to something like this:  =ROUNDUP(SUM(D2:D65)/1024,0)

Where D65 is actually the last cell with the memory data in it, your row number will vary depending on how many VMs you have.

The ROUNDUP will round up the memory allocation (in case you have some VM’s with 4000MB allocated to them instead of 4096MB) and you need to divide the sum by 1024 to convert to GB of vRAM.

If you would rather run a PowerCLI script to gather the info, you can find a great article on how to do it here.

I hope your number turns out ok.  If it does not, all is not lost.  There are ways to shrink your vRAM footprint so the impact of the licensing is not as bad.  If you would like me to have a look, email me, I can provide a service to see how much vRAM you have allocated but never use.  That may prolong the next license purchase a bit or perhaps soften the expense.  The new licensing does not need to always be negative, maybe we just need to learn how to size our VMs with the licensing in mind.

UPDATE: If you copy and paste these formulas into Excel, the ASCII is different for some reason.  Just backspace over the quotes (“) and readd them.  The quotes are what Excel has an issue with.

VMware Virtual Storage Appliance (VSA) v1.0 – The Facts & The Features

 Storage, Tips and Tricks  4 Responses »
Jul 152011
 

VMware saw an issue with the SMB customers in that some were not adopting the higher editions of their software because most of the features required shared storage and some SMBs might not have been ready to bite off the costs of that storage.  So VMware decided to get creative and create a redundant shared storage solution using local storage.

Here are some of the features:

  • Deploys as an appliance, very easy to install
  • Must be deployed on a new ESXi 5.0 installation
  • Deploys a VSA Cluster Service on the vCenter server
  • The VSA Cluster Service can deploy the VSA “Agent VMs” to each of the ESXi 5.0 hosts
  • The appliance will use the local space available and present the storage on the network as an NFS datastore
  • Replicates the local storage to the local storage on another host in the cluster for redundancy.
  • If a host fails, the appliance storing the replica will immediately take over the failed “Agent VM’s” IP address and share the storage from the replica
  • v1.0 supports 2 or 3 ESXi hosts in a cluster (Typically for the essentials kits)
  • Sold as a separate SKU with one price with no license capacity restrictions (no technical size limits that I could find)
  • Supports 25 VMs (configured on 2 ESXi hosts) or 35 VMs (configured on 3 ESXi hosts)
  • It is the only scenario where VMware recommends running vCenter on a physical or standalone ESXi hypervisor (To protect you from running into a Catch-22 as vCenter is managing the VSAs
  • Recommended to use RAID10 on the hardware RAID controllers in the hosts (to protect from a single drive failure)
  • Uses RAID 1 (Mirroring) between hosts for redundancy
  • Supports Storage vMotion for when you are ready to migrate to hardware shared storage
  • Can put the whole VSA cluster in maintenance mode or just a single node.  Can also replace a node and have the VSA rebuild onto it for redundancy or for rolling upgrades.

Here’s how it works: Imagine I have 3 hosts numbered 1,2 and 3.  Once the VSA gets installed, it creates two volumes on the available local storage on each host.  So host 1 will have volumes 1A and 1B, host 2 has 2A and 2B, host 3 has 3A and 3B.  Once the VSAs are configured, they will be redundant so that 1A (which stores VMs) mirrors to 2B, 2A mirrors to 3B and 3A mirrors to 1B.  If any VSA get’s dropped, the VSA running the mirror copy takes the IP address of the failed VSA and keeps right on chugging.

My Take

The Pros: Great solution for SMBs without shared storage to take advantage of HA, vMotion, etc.  I also think this is an outstanding solution for companies with remote offices who want to have redundancy in 2 or 3 ESXi hosts but don’t want to put shared storage in each site.

The Cons:  Way too much overhead.  VMware is recommending hardware RAID10 from the local drives if possible.  If I have 4 x 1TB drives in a server (4TB RAW disk capacity).  I use RAID10 as per VMware’s recommendation, this means 2TB gets presented to the ESXi host.  Now the VSA uses half of that storage for VMs and half as a target to mirror the VSA from one of the other hosts.  So out of 4TB of RAW disk, I get <1TB of capacity to store VMs on (don’t forget, I need room to store ESXi itself).  Thats a 75% reduction from RAW capacity = too much overhead.

Overall I still think it’s worth it.  It’s still going to be less expensive that a shared storage frame (even with the overhead loss).  I think for remote sites, you can’t beat it.  I can’t wait to see what they add to it in v2.0.

VMware vSphere 5: The BIG feature list

 Administration, Performance, Software Releases, Storage, VMware News  14 Responses »
Jul 132011
 

As I was wading thru all of the new materials from yesterday, I thought it would be helpful to create a big list of all of the new features in vSphere 5.0.  There were really only a few named in the presentation (or else the preso would have been 3 hours and put the analysts to sleep).  While we wait for the release notes, I put together this list for you.  This is not every new feature, but rather as many as I could find or remember.  I’ve also added a quick blurb on what that feature does and my comments in parenthesis.  If you are aware of something that I missed, please add in the comments below (with your own comments/opinions of course).  Here we go:

VMware vSphere 5.0

  • ESXi Convergence – No more ESX, only ESXi (they said they would do it, they meant it)
  • New VM Hardware:  Version 8 – New Hardware support (VS5 still supports VM Hardware 4 & 7 as well if you still want to migrate to the old hosts)
    • 3D graphics Support for Windows Aero
    • Support for USB 3.0 devices
  • Platform Enhancements (Blue Requires Hardware v8)
    • 32 vCPUs per VM
    • 1TB of RAM per VM
    • 3D Graphics Support
    • Client-connected USB devices
    • USB 3.0 Devices
    • Smart-card Readers for VM Console Access
    • EFI BIOS
    • UI for Multi-core vCPUs
    • VM BIOS boot order config API and PowerCLI Interface
  • vSphere Auto Deploy – mechanism for having hosts deploy quickly when needed ( I’m going to wait and see how customers use this one.)
  • Support for Apple Products – Support for running OSX 10.6 Server (Snow Leopard) on Apple Xserve hardware. (although I betting technically, you can get it to run on any hardware, you will just not be compliant in your license) Continue reading »

vSphere and MSCS

 Administration, Storage, Tips and Tricks  9 Responses »
Aug 182009
 

Many of my users out there run Microsoft Cluster Services on ESX.  A great questions was asked of me today: have the rules changed with running MSCS on vSphere?  The answer is: a little.

There are 3 scenarios of MSCS clusters and ESX: Cluster-in-a-box (both MSCS nodes are on the same physical host – great for testing), cross-host (where each of the MSCS node VMs resides on different ESX hosts), and physical-virtual (where one MSCS node is physical, one is virtual).  The requirements for MSCS can change, even in the minor updates, so check the documentation often.  Here’s my compiled list of requirements/tips for MSCS on ESX 4.0:

  • You are still limited to two-node clusters with MSCS on ESX 4.
  • From a storage perspective, you can use local storage (for cluster-in-a-box) or Fiber Channel (for cross-host or physical-virtual clusters).  There is still no support for NFS or iSCSI (I personally think this is because FC and local storage have more predictable performance – although iSCSI is improving on this).
  • If you are doing cross-host, both hosts must be running the same version of ESX (this just makes sense really).
  • The MSCS node VMs cannot move as part of HA or DRS.  (HA is being a little redundant for MSCS, DRS is because MSCS is so hyper-sensitive to network connectivity that even a ping loss could failover the MSCS cluster).
  • You cannot use MSCS with Fault Tolerance  (i.e. FT VM’s can reside on the same physical ESX hosts, but MSCS node VMs cannot run as FT pairs)
  • You cannot vMotion MSCS node VM’s.  (Same reason as DRS).
  • You cannot use N-Port ID Virtualization (NPIV)
  • If you are using FC and using the native multipathing in ESX, you cannot use round robin as a path policy.
  • You must use VM hardware version 7 with ESX/ESXi 4.0 (if you migrated the VMs from ESX 3.5 or before, make sure to upgrade your VM hardware version)
  • Failover clustering with Windows Server 2008 is not supported with virtual compatibility mode RDM’s, for Win2008 use physical compatibility mode RDMs.
  • You cannot use thin-provisioned disks for the Windows OS vmdk’s, they have to be thick.
  • For Win2000 and Win2003 use LSI Logic Parallel as the controller type for the shared storage.  For Win2008 use LSI Logic SAS.
  • For physical-virtual MSCS clusters, use RDMs in physical compatibility mode (this just makes sense if you think about it)
  • You cannot run storage multipathing software in the VMs or on ESX (i.e. no PowerPath VE).
  • You cannot over-commit memory for the MSCS node VMs, set the Memory Reservation option for each of the nodes to the amount of memory assigned to the virtual machine.
  • Set the disk I/O timeout to 60 sec. or more (HKLM\System\CurrentControlSet\Services\Disk\TimeOutValue) in the registry.

You can find all the details and steps walking you thru the setup of MSCS on ESX in this article .  If you’re not on vSphere yet but you want to run MSCS nodes as VMs, you can find the proper docs for your version of ESX in a freshly updated KB article located here .

How does Fault Tolerance prevent a split brain scenario?

 Administration, Disaster Recovery  1 Response »
May 222009
 

I’m training all of my partner engineers this week and they always ask the toughest technical questions.  Thanks to Scott Phillips for asking me this one:

What does Fault Tolerance do to prevent a split brain if both Primary and Secondary VMs become isolated?

Fault Tolerance (FT) uses an on-disk generation number file.  When FT is enabled the primary VM creates a file on shared storage called generation.N where N is a counter number.  The secondary VM is started and when it connects to the primary, the primary tells the secondary what the generation number is.  Once the Primary or secondary detects that there is a failure in the other half of the VM pair, it will try to rename the generation.N file to generation.N+1.  If the rename succeeds, the VM takes over as being the Primary (or remains the primary if it already was) and takes corrective action to rebuild a secondary and become protected again.  If the rename of the generation.N file fails, that means that the other VM in the pair already renamed the file and took over and the current VM shuts down.

There you have it, the disk subsystem prevents both VM’s from becoming the primary at the same time and creating a split brain.

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