Topic
6 replies Latest Post - ‏2010-01-29T07:49:44Z by SystemAdmin
SystemAdmin
SystemAdmin
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Pinned topic Using Read/Write enable Virtual Optical Device

‏2010-01-22T04:20:56Z |
Hi,

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(2.1.2.10-FP-22) and load it on my virtual target device.

$ lsrep
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
scsibus0:
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 :
Supported modes:
wodim: Warning: controller does not support CD write parameter page.
wodim: Cannot set speed/dummy.

My Question:

・ Is there any information that Linux(on Power) does not support writing on virtual disks?

Thanks,
Updated on 2010-01-29T07:49:44Z at 2010-01-29T07:49:44Z by SystemAdmin
  • SystemAdmin
    SystemAdmin
    706 Posts
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    Re: Using Read/Write enable Virtual Optical Device

    ‏2010-01-24T23:37:22Z  in response to SystemAdmin
    a little bit of more info,
    checked the /proc directory, and it seems that writing is not supported

    1. cat /proc/sys/dev/cdrom/info
    CD-ROM information, Id: cdrom.c 3.20 2003/12/17

    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?

    thanks,
    • SystemAdmin
      SystemAdmin
      706 Posts
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      Re: Using Read/Write enable Virtual Optical Device

      ‏2010-01-26T16:53:30Z  in response to SystemAdmin
      Hi, we're currently investigating this. We'll provide more definitive information in this thread shortly.
  • SystemAdmin
    SystemAdmin
    706 Posts
    ACCEPTED ANSWER

    Re: Using Read/Write enable Virtual Optical Device

    ‏2010-01-27T09:25:34Z  in response to SystemAdmin
    Thank 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

    VTD lp48_cd
    Status Available
    LUN 0x8100000000000000
    Backing device /var/vio/VMLibrary/RHEL53
    Physloc

    VTD lp48_sda_SAN
    Status Available
    LUN 0x8300000000000000
    Backing device hdisk8
    Physloc U7311.D20.066698B-P1-C07-T1-W200600A0B8502F3D-L6000000000000

    VTD vtopt0
    Status Available
    LUN 0x8200000000000000
    Backing device cd0
    Physloc U787F.001.DPM35L8-P4-D2

    <From RHEL 5.3 >

    lsvio -d
    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

    cat /proc/sys/dev/cdrom/info
    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

    Thanks,
    • SystemAdmin
      SystemAdmin
      706 Posts
      ACCEPTED ANSWER

      Re: Using Read/Write enable Virtual Optical Device

      ‏2010-01-27T09:29:43Z  in response to SystemAdmin
      Sorry,
      forgot to explain that above was tested on a different machine, which RHEL 5.3.

      Still both, SLES11 and RHEL 5.3 reports, writing aren't supported

      thanks,
      • Brian_King
        Brian_King
        20 Posts
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        Re: Using Read/Write enable Virtual Optical Device

        ‏2010-01-28T18:30:45Z  in response to SystemAdmin
        After 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?
        • SystemAdmin
          SystemAdmin
          706 Posts
          ACCEPTED ANSWER

          Re: Using Read/Write enable Virtual Optical Device

          ‏2010-01-29T07:49:44Z  in response to Brian_King
          Thank 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.

          Thank you,