Red Hat Bugzilla – Bug 993530
Reading from a physical cdrom is very slow, dmesg can show bad sectors
Last modified: 2013-12-16 14:43:59 EST
Description of problem:
When i use a Windows CDROM for install it in a KVM machine, the reading of the cdrom is very slow, like 8x. The installation time is more prolonged and i can listen like the dvd-rom read slowly compared to virtualbox that make runs faster the cdrom like a native cdrom of the guest.
Version-Release number of selected component (if applicable):
Fedora 18 x86_64 up to date.
[ 1.836184] systemd-udevd: starting version 201
[ 4.830171] systemd-udevd: starting version 201
[ 1.748126] scsi 3:0:0:0: CD-ROM HL-DT-ST DVDRAM GH22NS50 TN03 PQ: 0 ANSI: 5
[ 1.752890] sr0: scsi3-mmc drive: 48x/48x writer dvd-ram cd/rw xa/form2 cdda tray
[ 1.753092] cdrom: Uniform CD-ROM driver Revision: 3.20
[ 1.753281] sr 3:0:0:0: Attached scsi CD-ROM sr0
always using a cdrom with qemu-kvm
Steps to Reproduce:
1.insert a windows xp sp2 cd
2.create a new virtual machine, kvm, ide, default all and select cdrom as source
3.install and listen and see the time compared with virtualbox and listen the sound of rotation of the cdrom motor, is very slow with qemu-kvm compared with virtualbox that sounds like native box (fedora 18 runs normal and faster).
Installations using cdrom are much more slower than using .iso image
cdrom reading using qemu-kvm equal faster than host (fedora 18)
The host cdrom passthrough in qemu is known to not be particularly reliable, so this isn't surprising.
F18 is end-of-life soon, so nothing is unlikely to change there. Please reopen if this bug still affects F20+