Tuesday, September 29, 2009

ESX Host Loses Connectivity Briefly

I have seen this issue with ESX 3.5 Update 2 and Update 4, the host disconnects briefly from the console and there are no real error messages in VirtualCenter other than indicating the disconnection.

Some research revealed that this is due to a memory leak in hostd. To mitigate the issue, I increased the Service Console memory 800 MB and the modified the soft and hard memory limits in the config.xml file.

You can identify this issue from the following errors in /var/log/vmware/hostd.log:

[2009-09-29 01:25:54.857 'Memory checker' 19467184 warning] Current value 204800 exceeds soft limit 122880.
[2009-09-29 01:26:24.868 'Memory checker' 18668464 warning] Current value 204800 exceeds soft limit 122880.
[2009-09-29 01:26:54.879 'Memory checker' 3076465568 error] Current value 204852 exceeds hard limit 204800. Shutting down process.

To change the console memory configuration from the default of 272 MB with ESX 3.5 to the max of 800 MB, edit the memory settings from VirtualCenter under Configuration -> Memory -> Properties. This change requires a server reboot.

To change the hard/soft limits, add the following into the <config> section of /etc/vmware/hostd/config.xml
<hostdWarnMemInMB>300</hostdWarnMemInMB>
<hostdStopMemInMB>380</hostdStopMemInMB>

Do a restart on hostd process by:
service mgmt-vmware restart

Monday, September 28, 2009

Unable to Apply DRS Resource Settings on Host

"Unable to apply DRS resource settings on host (Reason: A general system error occurred: Invalid fault). This can significantly reduce the effectiveness of DRS"

Check each VM running on the host to make sure VMTools is unmounted. I had one machine with the tools still mounted, as soon as I ended the tools install, the error resolved on its own and the host was fully integrated into the cluster.

Friday, September 25, 2009

Error 25003. Setup failed to create the vCenter Server repository

http://www.vmware.com/support/vsphere4/doc/vsp_esxi40_vc40_rel_notes.html

  • vCenter Server installation on Windows Server 2008 with a remote SQL Server database fails in some circumstances
    If you install vCenter Server on Windows 2008, using a remote SQL Server database with Windows authentication for SQL Server, and a domain user for the DSN that is different from the vCenter Server system login, the installation does not proceed and the installer displays the following error message:
    25003.Setup failed to create the vCenter repository.
    Workaround: In these circumstances, use the same login credentials for vCenter Server and for the SQL Server DSN.
  • Monday, September 21, 2009

    Storage vMotion Enhancements

  • Improved scalability
  • Improved performance
  • Less resource utilization
  • UI support
  • Migrate between thick and thin disks
  • Convert RDMs to VMDKs
  • No memory doubling requirement
  • Move a VM's storage from VMFS to NFS
  • Change storage while VM is running
  • Saturday, September 19, 2009

    Quick Hit - New vSphere 4 Storage Features

    Paravirtualized iSCSI
  • What: This is a driver for high performance storage adapters
  • Benefits: It offers greater throughput and lower CPU utilization
  • When to use it: For very I/O intensive applications

    VMDirect I/O for Storage
  • What: Enables VMs to directly access the underlying hardware
  • Benefits: Enhances CPU efficiency in applications with constant and frequent I/O
  • Drawbacks:
         1) VMotion is not available
         2) HBA is not shareable by other VMs

    Virtual Disk Thin Provisioning
  • What: Space is allocated on an as-needed basis in 1 MB chunks
  • Benefits:
         1) Improves storage efficiency
         2) Increases utilization rates
         3) Reduces storage costs
  • Drawbacks: You could over provision the disks and run out of space, so monitoring of resources is essential.
  • How to Enable Hot Add CPU and Memory in vSphere

    In vSphere, there is a new feature, hot add memory and CPU. This is very cool as downtime can be avoided which is, at least in my company, very helpful during daily operations. This feature is not enabled by default. To enable these features, do the following:

    1. Make sure the virtual machine hardware is upgraded to version 7, if it is not, then right click the VM and choose 'Upgrade Virtual hardware'. You can find the hardware version by clicking on the 'Summary' tab.



    2. Go to edit settings for the VM, then the options tab, under 'Advanced', select 'Memory/CPU hotplug' and in the pane to the right, enable the memory hot add and CPU hot plug features. This change must be made when the VM is powered down. If the VM is running, the options will be greyed out as in the image below.



    Hot add memory and CPU is not supported by all OS's, Windows 2008 Enterprise 64 bit edition is one of the suppoted OS's, for a complete list, take a look at the Guest OS Guide.

    Thursday, September 17, 2009

    Windows 2008 Activation - 0x8007232B – DNS name does not exist

    When trying to activate a Windows 2008 standard server recently, I received error '0x8007232B - DNS name does not exist'.  The error description 'DNS name does not exist' can be misleading, the error occured because an invalid product key was entered.  If you didn't enter a product key during setup and then try to activate you will also receive this error.  Just correct the product key and activation will work.

    Friday, September 11, 2009

    Restart VMware Management Service

    When all else fails..., run:

    "service mgmt-vmware restart"

    Recycling this service has cleared up many errors, I keep it handy. Case in point, the following error was thrown and then I lost control of the CD-ROM in one of my VMs. I recycled the VM and I still couldn't access the CD.

    Error message:




    Before recycling service:



    After recycling service:

    Friday, September 4, 2009

    The Session is not Authenticated

    When using the VMware vCenter Converter Standalone tool, you may find that when you get to step 2 - 'Specify Destination', you sometimes get the error 'The session is not authenticated'. There are two possible fixes that I know of. First, try killing the vmware-converter-a.exe process from task manager. If that does not work, you are probably converting a live machine, so go to that machine and recycle the 'VMware vCenter Converter Agent' service.

    Mount and Unmount a CD in Linux

    Mount:

    mount -t auto /dev/cdrom /mnt/cdrom

    Unmount:
    umount /mnt/cdrom

    In case of 'device is busy' when unmounting, try the 'lazy' unmount:
    umount -l /mnt/cdrom