VMware Solutions Discussions

Multiple VM SCSI Controllers and Snapdrive


Hi All,

We're in the process of planning an upcoming Windows SAP environment hosted in a Vmware ESXi 5 environment.  We have a particular disk layout in mind using a combination of VMDK (over NFS datastores) and FC RDM's.  As per requirements / best practice for SAP, we have around 7 FC RDM's, plus 4 vmdk's (plus OS/pagefile/etc) per guest.

We have planned to use 3 or 4 separate VM SCSI controllers to separate datafile, logfile, binaries and OS disks.  This is for performance reasons and because we're closing in on the 15 disk limit per SCSI controller.  So, an example of the config we're looking for is this:

We produced this by manually creating/mapping the LUNs on filers and mapping them through to the guest in vcenter.  However, we would prefer to use SnapDrive (we're using version 6.3.1 on Windows 2008) to do all of this for us, but there doesn't seem to be a way to tell SnapDrive which guest SCSI controller to use when creating/connecting the RDM's.  Does anyone know if this is possible with SnapDrive (apologies if I've missed something), or if not how SnapDrive decides which controller to use when creating new LUN's?

Thanks in advance,




Hi there,

currently it is not possible to do so. You can attach luns using snapdrive and reconfigure the hdd to a different scsi controler afterwards. it does need a vm downtime.




Hi Thomas,

Thanks.  We did try that, but the combination of adding the new SCSI controllers and changing the guest config seemed to have broken snapdrive after bringing the VM back up.  The SDW GUI just hung and a service restart didn't help.  I didn't troubleshoot it at the time, but maybe I'll try it again when I get time.

We suspected the problem is the addition of the SCSI controllers after snapdrive is installed.  We couldn't add the SCSI controllers first as you need a disk to connect to the VM first (back to creating everything manually).  That said we're going to see if we can add the scsi controllers to the template's vmx file before we deploy it, if that works we'll try creating the RDM's in snapdrive, then reconfiguring them to the correct scsi controllers as you describe.  I'll report back...

Out of interest, does anyone know if this capability is pencilled in for any future release?