6.5.1

Table Of Contents
About VMware Paravirtual SCSI Controllers
VMware Paravirtual SCSI controllers are high performance storage controllers that can result in greater
throughput and lower CPU use. These controllers are best suited for high performance storage
environments.
VMware Paravirtual SCSI controllers are available for virtual machines with ESXi 4.x and later
compatibility. Disks on such controllers might not experience optimal performance gains if they have
snapshots or if memory on the ESXi host is over committed. This behavior does not mitigate the overall
performance gain of using VMware Paravirtual SCSI controllers as compared to other SCSI controller
options.
If you have virtual machines with VMware Paravirtual SCSI controllers, those virtual machines cannot be
part of an MSCS cluster.
For platform support for VMware Paravirtual SCSI controllers, see the VMware Compatibility Guide at
http://www.vmware.com/resources/compatibility.
Add a Paravirtualized SCSI Adapter in the vSphere Web Client
You can add a VMware Paravirtual SCSI high performance storage controller to a virtual machine to
provide greater throughput and lower CPU use.
VMware Paravirtual SCSI controllers are best suited for environments, especially SAN environments,
running I/O-intensive applications.
For information about SCSI controller maximums and virtual device assignments, see SCSI and SATA
Storage Controller Conditions, Limitations, and Compatibility.
Prerequisites
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Verify that the virtual machine has a guest operating system with VMware Tools installed.
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Verify that the virtual machine compatibility is ESXi 4.x and later.
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Ensure that you are familiar with VMware Paravirtual SCSI limitations. See About VMware Paravirtual
SCSI Controllers.
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To access boot disk devices attached to a VMware Paravirtual SCSI controller, verify that the virtual
machine has a Windows 2003 or Windows 2008 guest operating system.
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In some operating systems, before you change the controller type, create a virtual machine with an
LSI Logic controller, install VMware Tools, and then change to paravirtual mode.
Procedure
1 Right-click a virtual machine in the inventory and select Edit Settings.
2 On the Virtual Hardware tab, select SCSI Controller from the New device drop-down menu and
click Add.
The controller appears at the bottom of the Virtual Hardware device list.
vSphere Virtual Machine Administration
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