Disable SCSI-Reservation at the driver level ?

["roland" <devzero@web.de>]

Hello !

i have a "problem" with VMWare ESX (not big one, but interesting one - at 
least for me).

If you don`t know VMware ESX - ESX is sort of it`s own operating system with 
Linux as a management console OS on top of a hypervisor (vmkernel), just 
similar to XEN hypervisor with and attached dom0. Besides the drivers in the 
console OS, the vmkernel loads it´s own drivers, which are derived from 
Linux drivers.

VMWare ESX refuses to create VMFS Filesystem on SATA disk, attached to a 
onBoard SAS controller (lsi1068).
When i raid1 two SATA disks, it works, if i use a single SATA disk, the 
controller seems to "expose" the disk differently to the operating system 
and creation of a VMFS fails due to missing ability to issue SCSI 
reservation command.

Ok there is no official SATA support for now, but some controllers work with 
SATA,  because you can either attach SAS and SATA disks to that (LSI1068). 
Furthermore there are SATA-controllers which can be used with the driver of 
some SCSI-model (LSI Megaraid 150-4)

Afaik, SCSI reservations being used/needed in shared storage environment 
(SAN, Shared local attached storage), so i wonder, why it's also being used 
on local attached disk. Only vmware may give an answer here.

Maybe i can can "workaround" this somehow ?
I couldn`t find a way to stop the vmkfstools (which is used to format 
blockdevice with VMFS) issueing a SCSI reservation command, but i assume 
this can probably be done via filtering some syscall (ioctl?) via LD_PRELOAD 
library - i.e. wrapping vmkfstools - or maybe i can hack this at the driver 
level, since source of the ESX storage drivers is available for download and 
can be recompiled. :)

if somebody like to help hacking this -  there is a thread at:
http://www.vmware.com/community/thread.jspa?messageID=518182&#518182
thread begins with some related iSCSI issues and discusses SATA issues later 
on.

regards
Roland

ps:
yes, i know this is somhow "evil" and i shouldn`t do that, because something 
could badly fail -  but it`s for private purpose, for proof of concept and 
for personal satisfaction. :) i´m not going to use such hack on any 
production system. 

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