Blog: SCSI

I was adding a new SCSI/SATA controller card to an HP MSA 1510i. I had shut down the unit to perform the work and after rebooting I could not connect to the management interface. I checked the small interface on the front and the system was attempting to get a DHCP address. I reset the address for management and was able to connect but the password had reset to the default. At that point I determined it had dumped its configuration. [more]

The LUNs were fine just could not communicate over iSCSI. If you have ever configure a MSA 1510i you know they are not very straight forward. I was able to get everything back communicating and the VMware servers back online without too much trouble. Lesson learned was to make sure and document the configuration of a device or back it up. Unfortunately the MSA 1510i does not allow configuration backups. It’s also good to document because I had lost access to information at our office, such as passwords and IPs, because the ISA server (which is a VM) was offline.


I was trying to add a scsi controller to a ESX box to use in a VM running on the box. The ESX operating system recognized the PCI-based Adaptec controller (it was on the HCL) but when I added the SCSI controller to the VM, it would not boot and displayed the following error:

Unable to open SCSI device 'vmfs/devices/genscsi/vmhba3:5:0:0'(scsi3:0):Could not find the file. Failed to configure scsi3.

The problem was that there was an extra “:0” at the end of the file name. I edited the .vmx file for the virtual machine and it worked! Note that also you need to edit with wordpad (not notepad) because of the construct of the .vmx file. [more]

edit vmx file
Edit ******.vmx (wordpad, etc...)

scsi0:1.present = "true"
scsi0:1.deviceType = "scsi-passthru"
scsi0:1.fileName = "/vmfs/devices/genscsi/vmhba3:5:0:0"
scsi0:1.allowGuestConnectionControl = "false"

scsi0:1.present = "true"
scsi0:1.deviceType = "scsi-passthru"
scsi0:1.fileName = "/vmfs/devices/genscsi/vmhba3:5:0"
scsi0:1.allowGuestConnectionControl = "false"

I was able to find a solution in the following VMware Communities thread:


There are two SCSI driver standards that are available for most SCSI HBA’s. The older standard (SCSIport) has been replaced by a newer technology (STORport). STORport allows faster I/O, duplexing and other advantages. You should use the STORport drivers for all HBA’s when available. This is especially revelant for FC cards. The details are: [more]

Classic SCSI (SCSIPort):

  • commands were queued on an adapter/LUN basis
  • Maximum number of I/O's per adapter is 256, with 16 LUN's per adapater
  • Queue limit on LUN level, with a maximum of 20 outstanding I/O's
  • If one LUN reaches it's limits all other LUN's will be blocked as well
  • Will remain for direct attached storage


  • No limitation on adapter queues
  • Each LUN has a queue limit of 256 outstanding I/O's
  • Designed for Fibre Channel attached storage
  • Exchange and SQL will probably not be using Storport directly
  • Except for SQL RAW disk functionality which will bypass volume management (for higher performance)

More details: