I'm thinking of way to use VIOS's file-backed virtual optical device, for backing up my data.
First I've made a read-write enabled virtual disk on my VIOS(126.96.36.199-FP-22) and load it on my virtual target device.
Size(mb) Free(mb) Parent Pool Parent Size Parent Free
10126 0 vopt_vg 10168 0
Name File Size Optical Access
SLES11_DVD1 2885 None rw
SLES11_DVD2 3734 None rw
rw_device 3507 lpar510_cd rw
(the "rw_device" is the virtual disk, and "lpar510_cd" is the virtual target device)
However on when i try to format the disk on my SLES 11 machine I get the flowing error indicating me that "controller does not support CD write parameter page."
lpar510:~ # cdrecord -scanbus
0,0,0 0) 'AIX ' 'VOPTA ' '' Removable CD-ROM
0,1,0 1) *
0,2,0 2) *
0,3,0 3) *
0,4,0 4) *
0,5,0 5) *
0,6,0 6) *
0,7,0 7) *
lpar510:~ # cdrecord blank=fast dev=0,0,0
WARNING: the deprecated pseudo SCSI syntax found as device specification.
Support for that may cease in the future versions of wodim. For now,
the device will be mapped to a block device file where possible.
Run "wodim --devices" for details.
Device type : Removable CD-ROM
Version : 4
Response Format: 2
Capabilities : CMDQUE
Vendor_info : 'AIX '
Identification : 'VOPTA '
Revision : ''
Device seems to be: Generic CD-ROM.
wodim: Sorry, no CD/DVD-Recorder or unsupported CD/DVD-Recorder found on this target.
Using generic SCSI-2 CD-ROM driver (scsi2_cd).
Driver flags :
wodim: Warning: controller does not support CD write parameter page.
wodim: Cannot set speed/dummy.
・ Is there any information that Linux(on Power) does not support writing on virtual disks?
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6 replies Latest Post - 2010-01-29T07:49:44Z by SystemAdmin
Pinned topic Using Read/Write enable Virtual Optical Device
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Updated on 2010-01-29T07:49:44Z at 2010-01-29T07:49:44Z by SystemAdmin
Re: Using Read/Write enable Virtual Optical Device2010-01-24T23:37:22Z in response to SystemAdmina little bit of more info,
checked the /proc directory, and it seems that writing is not supported
- cat /proc/sys/dev/cdrom/info
drive name: sr0
drive speed: 1
drive # of slots: 1
Can close tray: 1
Can open tray: 1
Can lock tray: 1
Can change speed: 0
Can select disk: 0
Can read multisession: 1
Can read MCN: 1
Reports media changed: 1
Can play audio: 1
Can write CD-R: 0
Can write CD-RW: 0
Can read DVD: 0
Can write DVD-R: 0
Can write DVD-RAM: 0
Can read MRW: 0
Can write MRW: 0
Can write RAM: 0
from this may I conclude that you CANNOT write on a virtual disk?
Re: Using Read/Write enable Virtual Optical Device2010-01-27T09:25:34Z in response to SystemAdminThank you for your support,
Here's more information if it helps.
When mapping a physical cd drive to a virtual optical device, the driver information says that it is capable of writing DVD-RAMs. (only)
<FROM VIOS >
( lp48_cd is File-backed optical device, vopt0 is a virtual scsi device mapped to a physical cd)
lsmap -vadapter vhost5
SVSA Physloc Client Partition ID
vhost5 U9131.52A.067F69G-V1-C108 0x00000008
Backing device /var/vio/VMLibrary/RHEL53
Backing device hdisk8
Backing device cd0
<From RHEL 5.3 >
300000d0 v-scsi U9131.52A.067F69G-V8-C208-T1
1:0:2:0 sg1 sdb U9131.52A.067F69G-V8-C208-T1-L1-L0
3000006c v-scsi U9131.52A.067F69G-V8-C108-T1
0:0:2:0 sg3 sr1 U9131.52A.067F69G-V8-C108-T1-L0-L0
0:0:1:0 sg2 sr0 U9131.52A.067F69G-V8-C108-T1-L0-L0
0:0:3:0 sg0 sda U9131.52A.067F69G-V8-C108-T1-L0-L0
CD-ROM information, Id: cdrom.c 3.20 2003/12/17
drive name: sr1 sr0
drive speed: 24 1
drive # of slots: 1 1
Can close tray: 1 1
Can open tray: 1 1
Can lock tray: 1 1
Can change speed: 1 0
Can select disk: 0 0
Can read multisession: 1 1
Can read MCN: 1 1
Reports media changed: 1 1
Can play audio: 1 1
Can write CD-R: 0 0
Can write CD-RW: 0 0
Can read DVD: 1 0
Can write DVD-R: 0 0
Can write DVD-RAM: 1 0
Can read MRW: 1 0
Can write MRW: 1 0
Can write RAM: 1 1
sr1 shows that it can handle DVD-RAM
Brian_King 120000K4SY20 PostsACCEPTED ANSWER
Re: Using Read/Write enable Virtual Optical Device2010-01-28T18:30:45Z in response to SystemAdminAfter some investigation, we've been able to reproduce the problem you are having. Unfortunately, we don't currently have a fix or workaround. I would encourage you to open a PMR for this issue. As an alternative, would using a logical volume backed virtual disk for your backup be a possible solution?
Re: Using Read/Write enable Virtual Optical Device2010-01-29T07:49:44Z in response to Brian_KingThank you very much for your support!
I understand the situation for no fix or workaround.
As for the alternative, actually i was unaware of "logical volume backed virtual disk".
I'll try it out, and give feedback.