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From Sateesh Chodapuneedi <>
Subject [PROPOSAL] Granular Controller Support in CloudStack over VMware deployments
Date Mon, 17 Feb 2014 04:47:40 GMT

I would like to add support for granular disk controller support for CloudStack over VMware

To access virtual disks, CD/DVD-ROM, and SCSI devices, a virtual machine uses storage controllers.

Virtual storage controllers appear to a virtual machine as different types of controllers
of type IDE or SCSI. Further SCSI controllers can be classified into 4 sub types, as below
    BusLogic Parallel
    LSI Logic Parallel,
    LSI Logic SAS
    VMware Paravirtual SCSI

Currently CloudStack supports following combinations only.
    DATA volumes - SCSI controller (LSI Logic Parallel) - Hard coded in source code, no option
for user to edit/choose the controller type
    ROOT volumes - IDE or SCSI (LSI Logic Parallel) - Baed on value of global configuration
parameter "vmware.root.disk.controller"

Currently the instances are deployed with the the LSI Parallel controller type. This might
result in failure to boot when attempting to deploy templates that use the LSI SAS controller.

CloudStack should provide administrator the means to choose the type of disk controller (including
sub types listed in introduction section above) for an instance. The controller to be used
by VM to access virtual disk (volume) can decided for various reasons. Some of them are listed
*   Some controllers are optimized for best performance over specific backend infrastructure
like SAN. Ex: VMware Paravirtual SCSI
*    Compatibility of some controllers with VM's virtual hardware version or guest operating
*    Operating system vendor recommendation and default set of drivers distributed as part
of operating system image. Ex: Windows 8.1 ISO doesn't have Lsi Logic Parallel SCSI drivers
by default. Hence a virtual disk attached to this controller won't accessible during installation
of OS using the ISO.

CloudStack should provide administrator an option which auto detects the recommended disk
controller for the instance's guest operating system and applicable virtual hardware version.
Kindly let me know your thoughts.

JIRA ticket - CLOUDSTACK-4787

Note:- Detailed Functional Specification is to be added at under 4.4 Design
documents. Currently is down. Waiting for the site to come up to add the
FS document.


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