Limit of IDE virtual disk emulation. When will XenServer get off IDE virtual disk emulation and use SATA and/or SCSI?
From Citrix XenServer Virtual Machine User's Guide":
"During the installation of a Windows operating system, XenServer uses traditional device emulation to present a standard IDE controller and a standard network card to the VM." & "For Windows or other fully virtualized guests, XenServer emulates an IDE bus in the form of an hd* device."
QEMU has IDE, virtio, SATA (AHCI), SCSI.
The XEN project itself seems to support SCSI:
"Xen guest interface ------------------- A Xen guest can be provided with block devices. These are always provided as Xen VBDs; for HVM guests they may also be provided as emulated IDE or SCSI disks."
This is mainly a Windows OS issue as most modern Linux's have xen drivers build in now. But a Windows OS install sees an IDE interface so you are limited to 3 hard drives, plus CD drive. This is an issue for a custom setup image that requires 4 or more separate drives, for security and/or performance reasons. It looks like all other Hypervisors allow more than IDE controller emulation.
All others seem to support: https://en.wikipedia.org/wiki/Comparison_of_platform_virtualization_software#Restrictions
The fact that XenServer seems to only offer, with no choice, the virtual disk controller as an IDE controller. "What year is this?" This is a very old and getting to be a show stopper, especially with Windows OS's. Just asking for my management. This is a major issue right now because we have a Windows custom image install that is looking for 4 disk drives, But obviously because XenServer is only doing IDE disk controller interface you can't... the CD drive to install and 3 disk...during install, BEFORE you can install xen-tools. It's a catch-22. Yes the config limits document states 255 disk drives but does NOT clearly state that this requires PV drivers to be installed. If only Microsoft Windows would include Xen drivers like Linux kernel does this may not be an issue. It appears other Hypervisors offer you to choose the type of Virtual disk controller.
Requesting other modern guest disk emulation like other vendors.