Re: [PATCH v6] libxl: allow 'phy' backend to use empty files

["Alex Braunegg" <alex.braunegg@gmail.com>]

Hi George,

> I take it that if he used a phy backend for a cdrom, that "xl cd-eject" failed?

No - I was always using ISO images for cd-rom devices. In the 4.4 configuration I was specifying it as a file.

In Xen 4.4 and 4.6 (before patching) whenever I attempted to perform an 'xl cd-eject' it always failed. I didn’t perform the triage of what commit broke the functionality - so I cant advise on if this is what broke it.

A sample of the configurations of what I used is below:

================

	# Xen 4.4
	builder='hvm'
	memory = 512
	name = 'CentOS_Test'
	disk = [ 'phy:/dev/zvol/storage/xen/CentOS_Test/disk_sda,hda,w','file:/storage/samba/xeniso/CentOS-6.5-x86_64-minimal.iso,hdc:cdrom,r' ]
	# boot on floppy (a), hard disk (c) or CD-ROM (d)
	# default: hard disk, cd-rom, floppy
	boot='cd'


	# Xen 4.6
	builder='hvm'
	memory = 512
	name = 'CentOS_Test'
	disk = [ '/dev/zvol/storage/xen/CentOS_Test/disk_sda,,hda','/storage/samba/xeniso/CentOS-6.5-x86_64-minimal.iso,,hdc,cdrom' ]
	# boot on floppy (a), hard disk (c) or CD-ROM (d)
	# default: hard disk, cd-rom, floppy
	boot='cd'

================

After patching Xen 4.6, I can now perform the xl cd-eject and load an alternate ISO into the VM without issue. However if I just want to eject the ISO as per what you would normally do on a physical system after install, I have to 'eject' but then insert a 'dummy' ISO file to keep the cd-rom device available to the VM through reboots / shutdowns:

	disk = [ '/dev/zvol/storage/xen/CentOS_Test/disk_sda,,hda','/storage/samba/xeniso/dummy.iso,,hdc,cdrom' ]

Without having some sort of valid 'dummy' ISO file that contains nothing, Xen has issues about creating the cd-rom device on creation and reboots, and certainly in the VM no cd-rom device is then available - meaning down the track if I want to load an ISO I cannot easily 'insert' another ISO file without powering off the VM, making the configuration change and powering the VM back on again.

It would be nice at some point to have the configuration where the cd-rom drive can presented to the VM without having a valid ISO / file loaded - which would then operate as per physical devices - cd-rom devices show up, but drive contents are empty:

	disk = [ '/dev/zvol/storage/xen/CentOS_Test/disk_sda,,hda',',,hdc,cdrom' ]

Best regards,

Alex



_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel