Those stats are equally impressive, since being able to achieve an almost 20% CPU decrease while increasing performance means more density per virtual host.  This further allows companies to squeeze more resources from their virtual infrastructure without needing to purchase more hardware.  And in this economy, everyone is trying to get their money’s worth when it comes to their infrastructure capital spending.

Since PVSCSI adapters are not supported for boot devices (they work, just not supported by VMware), you will need to add a 2nd hard drive to use the PVSCSI adapter.   When setting up a new virtual environment on vSphere for a client, it wasn’t clear where exactly that option is located.  It seemed when adding a 2nd hard drive, it just used the existing SCSI adapter.  On the VMware KB site, I found KB article 1010398 which talks about the steps to set that up.  Below are the details from the VMware KB site.  The most important step is #12, you NEED to select a SCSI adapter that starts from SCSI (1:0) through SCSI (3:15).  Selecting the next available SCSI interface, eg.  SCSI (0:1), uses the boot volume SCSI adapter.

When you select SCSI (1:0) or higher, you’ll see the new SCSI controller added.

1. Launch a vSphere Client and log in to an ESX host system.
2. Select a virtual machine, or create a new one.
3. Ensure a guest operating system that supports PVSCSI is installed on the virtual machine.  Currently:
   Windows Server 2008
   Windows Server 2003
   Red Hat Enterprise Linux (RHEL) 5

   Note: Booting from a disk attached to a PVSCSI adapter is not supported. The system software must be installed on a disk attached to an adapter that does support bootable disk.

4. In the vSphere Client, right-click on the virtual machine and click Edit Settings.
5. Click the Hardware tab.
6. Click Add.
7. Select Hard Disk.
8. Click Next.
9. Choose any one of the available options.
10. Click Next.
11. Specify the options your require. Options vary depending on which type of disk you chose.
12. Choose a Virtual Device Node between SCSI (1:0) to SCSI (3:15) and specify whether you want to use Independent mode.
13. Click Next.
14. Click Finish to finish the process and exit the Add Hardware wizard. A new disk and controller are created.
15. Select the newly created controller and click Change Type.
16. Click VMware Paravirtual and click OK.
17. Click OK to exit the Virtual Machine Properties dialog.
18. Power on the virtual machine.
19. Install VMware Tools. VMware Tools includes the PVSCSI driver.
20. Scan and format the hard disk.

I hope this helps anyone who wants to use the PVSCSI adapter, but is having trouble locating how exactly you add it to your virtual machine.  This vSphere update and the blog article referenced above from the VMware website is just another example that shows if you size your virtual environment correctly, you can virtualize even your highest demanding I/O enterprise applications.

VMware Fault Tolerance is leading edge technology that provides continuous availability for applications in the event of server failures,  by creating a live shadow instance of a virtual machine that is in virtual lockstep with the primary instance. By allowing instantaneous failover between the two instances in the event of hardware failure, VMware Fault Tolerance eliminates even the smallest of data loss or disruption.

At VMworld 2008 they let us play with a demo of VMware FT, and it really is an amazing technology.  Almost like watching your first VMotion (“You mean the VM moved from this server to that server?”).   VMware FT will allow you to have two running versions of the same virtual machine.  If you lose a host, the VM will continue running with no dataloss and minimal downtime (technically just a couple pings drop, but your users would not be likely to notice a disruption of service).  VMware FT does this by sending the same CPU instructions to both CPU’s via a FT logging NIC, which is a dedicated gigabit or better ethernet NIC on your vSphere hosts.

With any software that gives you that kind of power, there are some caveats and requirements to make FT work in your environment.   I felt it was a good idea to start a blog post that I could update with the various requirements for the use of FT with vSphere.  This list is my no means all-inclusive, but simply a place where I can keep track of the needs and caveats of FT.  Read more for my listing of requirements that I’ve found thus far.

Host Requirements:

CPU

• AMD Barcelona (Series 13xx, 23xx, 83xx)
• Intel Harpertown (Intel 31xx, 33xx, 52xx, 54xx, 74xx)
• Specifically a Hardware Virtualization (HV) enabled CPU
• Intel VT or AMD-V enabled in the BIOS
• Disable any power management in the BIOS (recommended)
• Disable Hyper Threading (recommended)

Network

• 2 FT Logging NIC (suggested)
• 1Gbps or better

Storage

• Shared
• Fiber Channel, iSCSI, or NAS

ESX

• Same build version of ESX on each host.
• VMware HA must be enabled on the primary and secondary hosts in the cluster.

Guest Requirements:

• All ESX supported guest OS’s, 32bit or 64bit
• One (1) vCPU  – vSMP is not yet supported.
• Thin-provisioned disks are not supported (they will be converted to thick)
• Paravirtualization is not supported
• Physically attached CD-ROM, Floppy not supported
• Physical RDM’s (Raw Device Mappings) not supported – Virtual RDM is supported.

Caveats:

• Storage VMotion not supported
• N-Port ID Virtualization (NPIV) not supported
• Need to have no single points of failure in any part of the environment (not required, but defeats the point of FT if your environment is not redundant).
• DRS can not be enabled on the protected VMs (You can still run manual VMotion’s)
• Hot add of of devices to the protected VMs is not supported
• Snapshots are not supported (must be deleted before protecting)
• VM Hardware must be at v7
• Remove 3rd party clustering solutions prior to enabling FT.

Anything else that I’m missing?  Let me know in the comments, and I’ll keep the above info updated.