This discussion is archived
7 Replies Latest reply: Dec 4, 2012 9:57 PM by BillyVerreynne RSS

root.sh hangs on redhat 5 using SAN multipathing

omari Newbie
Currently Being Moderated
Hi all,

I'm trying to install 10gr2 RAC on REDHAT 5.8. I'm using SAN multipathing everything is correctly configured and i also configured the raw binding using rawdevices script, then used UDEV to set the permissions correctly for the raw devices upon restart. when executing the root.sh i hit the bug 4679769 and resolved it. then i run the root.sh again it formats the voting and ocr successfully then hangs at the "Startup will be queued to init within 90 seconds" stage.

Regards,
omari
  • 1. Re: root.sh hangs on redhat 5 using SAN multipathing
    damorgan Oracle ACE Director
    Currently Being Moderated
    Have you found any evidence that 10gR2, put into desupport mode years ago, is supported on RedHat 5.8?
  • 2. Re: root.sh hangs on redhat 5 using SAN multipathing
    onedbguru Pro
    Currently Being Moderated
    1 - not sure 10gR2 is supported as damorgan noted - it makes no sense to install a desupported version.

    2. can the oracle user read and write to the device from ALL nodes in the cluster?

    3. did you partition the device? As a matter of practice, I make sure that the shared devices for RAC are partitioned where the partitioned used begins at cylinder <2>.
  • 3. Re: root.sh hangs on redhat 5 using SAN multipathing
    BillyVerreynne Oracle ACE
    Currently Being Moderated
    omari wrote:

    I'm trying to install 10gr2 RAC on REDHAT 5.8. I'm using SAN multipathing everything is correctly configured and i also configured the raw binding using rawdevices script, then used UDEV to set the permissions correctly for the raw devices upon restart.
    Old style Linux raw devices (creating a character device for a block device for direct I/O) is deprecated. Newer Linux kernels supports opening of block devices for direct I/O. Which means you can directly use block devices in ASM.

    Assuming minimal moving parts (no 3rd party SAN multipath and ASMLib), you only need udev/multipath. Via +/etc/multipath.conf+ you should configure logical multipath device names for the SAN LUNs. These multipath devices are what you should be using in ASM.

    LUN configuration via multipath is not complex. The deprecated rawdevices service and feature should not be used.

    Also 10gr2 is old - and its CRS s/w stack quite clunky compared to 11gr2 CRS. Why exactly do you not want to use 11gr2?
  • 4. Re: root.sh hangs on redhat 5 using SAN multipathing
    GauravAhuja Newbie
    Currently Being Moderated
    Hi,


    I don't think so using udev and and raw setting with multipathing is of any sense.

    Kindly use only multipathing, put permission for disks in rc.local file.

    Use udev only when you have single path devices, and multipath when you have multpath devices.

    /dev/mapper disks need to be used for ocr,votind and asm.

    because /dev/mapper disks are persistent, and set permission on this disk under rc.local file.


    Regards
    Gaurav
  • 5. Re: root.sh hangs on redhat 5 using SAN multipathing
    BillyVerreynne Oracle ACE
    Currently Being Moderated
    Gaurav Ahuja wrote:

    Kindly use only multipathing, put permission for disks in rc.local file.
    Agree with multipath. Disagree with using rc.local for setting device permissions.

    Multipath is dynamic - and configurations and unused devices can be flushed and reattached. Depending on the layer providing access to the devices (e.g. NFS, NAS, FCoE, SRP, SCST, etc), it can STILL be running and executing by the time rc.local is executed. Which means that rc.local will attempt to set permissions to devices that do not yet exist.

    Rather set permissions in +/etc/udev/rules.d/+ or +/etc/multipath.conf+ - allowing permissions to be applied consistently at the correct time, instead of permission settings being divorced from the device management process.
  • 6. Re: root.sh hangs on redhat 5 using SAN multipathing
    GauravAhuja Newbie
    Currently Being Moderated
    Respected Sir,


    But as per my knowledge /dev/mapper are persistent and are available from earlier stages of boot time.

    I know /udev/rules.d are also available to set permission on devices, but now where I ever found any problem with rc.local.

    My simple combination is to /dev/mapper and rc.local.

    Kindly Correct me with above combination where I can Get a Problem.


    Regards
    Gaurav
  • 7. Re: root.sh hangs on redhat 5 using SAN multipathing
    BillyVerreynne Oracle ACE
    Currently Being Moderated
    I believe that consistency is important.

    Consistency should be used in configuring device permissions for udev/multipath. Configuring static mappings in one location and dynamic mappings in another, are not consistent. Which means the person who maintains this after you, needs to know that 2 different approaches are used to set permissions, and needs to recognise what approach to use where and when. If that person then wrongly uses rc.local for a SAN/NAS device, this inconsistency leads to serious errors in the s/w stack due to incorrect device permissions.

    It is far simpler to manage that via a single configuration point - and for multipath devices that would be via udev rules in my case (I never got permission settings in multipath.conf to work properly, and udev rules allows more flexibility ito conditional branching and processing).

Legend

  • Correct Answers - 10 points
  • Helpful Answers - 5 points