Tag Archives: ESXi

Context switch can be 3 times slower in virtual environment such as VMware ESX

Tsuna analyzes how match time it takes to make a context switch. All analyzed chips are Multi-core Intel CPUs. OS / scheduler used – standard Linux Kernel.

Results: depends on what we call a context switch (theoretical / real world) and what we measure is: 1000 ns – 4500 ns (up to 45000 ns – depends on performance penalties involved).

However thing that I didn’t know is – context switch can be 3 times slower in virtual environment such as VMware ESX server or VMware Workstation.

VMware Guest OS: The trust relationship between this workstation and the primary domain failed

VMware Guest OS: The trust relationship between this workstation and the primary domain failed.

I received this errors two times on a row for two different computers.

I am not 100% sure, but from reading the web I came to conclusion that this error is encountered when:

  1. SID gets cloned when computer gets cloned using VMware. Not right after cloning, but at the random after some time.
  2. Guest OS gets reverted to some earlier snapshot.

In both cases leaving and joining Domain again fixes this issue.

P.S. Some time ago there was an utility called NewSID, but now it’s gone. NewSID has been retired and is no longer available for download. Please see Mark Russinovich’s blog post: NewSID Retirement and the Machine SID Duplication Myth.

VMware ESXi enable remote ssh access (unsupported)

To enable VMware ESXi 4.0 SSH (Windows Putty) access:

  • At physical console press ALT+F1. VMware ESXi banner will appear.
  • There is no prompt on the screen, but type ‘unsupported’ and press Enter.
  • Now at password prompt type root password.
  • You are logged in Linux console. Type:

vi /etc/inetd.conf

  • Locate line with commented SSH – ‘#ssh tcp …’, and uncomment it – delete ‘#’. (Press Insert to go into edit mode, delete ‘#’, press Esc to go back, type ‘:wq’ to save and quit.
  • Now you can restart server, or restart services using:

/sbin/services.sh restart

Tested on VMware ESXi 4.0.