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9 Replies Latest reply: Nov 13, 2012 10:48 PM by BillyVerreynne RSS

EMC PowerPath Compatibility

Linux-RAC-Admin Newbie
Currently Being Moderated
Does anyone have a Compatibility Matrix for EMC PowerPath with an older Oracle Linux kernel?

Currently I have -

Clariion CX3-40 array

# uname -r
2.6.18-92.el5

#powermt version
EMC powermt for PowerPath (c) Version 5.1 SP 2 (build 21)

And it is working fine!

But now my Storage Admin wants to connect it to a new EMC VNX 5500 array and it requires a newer PP version.

What is the highest version of PP I can upgrade to on the current kernel?

Thanks.
  • 1. Re: EMC PowerPath Compatibility
    Dude! Guru
    Currently Being Moderated
    EMC Powerpath 5.1.2 might be the highest version supported for RHEL x86_64 5.1. However, probably best to contact EMC or find a EMC support forum.
  • 2. Re: EMC PowerPath Compatibility
    BillyVerreynne Oracle ACE
    Currently Being Moderated
    Why taint the kernel with binary and proprietary vendor drivers? Each and every time you touch that kernel with even a minor patchset, proprietary drivers will cease to work as the kernel version changed.

    Why not use standard multipath instead? Open Source. Ships by default with Linux enterpise kernels. Does everything that Powerpath does - and more.

    Linux multipath/udev have their origins in some of the largest Linux cluster on this planet. It is robust software. And proven software.

    We have been using multipath for many years now - and are still using it on VNX SANs.
  • 3. Re: EMC PowerPath Compatibility
    898553 Newbie
    Currently Being Moderated
    Billy  Verreynne  wrote:
    Why taint the kernel with binary and proprietary vendor drivers? Each and every time you touch that kernel with even a minor patchset, proprietary drivers will cease to work as the kernel version changed.

    Why not use standard multipath instead? Open Source. Ships by default with Linux enterpise kernels. Does everything that Powerpath does - and more.

    Linux multipath/udev have their origins in some of the largest Linux cluster on this planet. It is robust software. And proven software.

    We have been using multipath for many years now - and are still using it on VNX SANs.
    This was going to be my suggestion as well. You can do a lot more tuning with dm-multipath than powerpath as well.
  • 4. Re: EMC PowerPath Compatibility
    Dude! Guru
    Currently Being Moderated
    As far as I know, EMC Powerpath contains optimizations to device fail-over algorithms and I/O performance of specific EMC hardware, at least for MS Windows. I'm not saying that there will necessarily be any performance difference under Linux, but it might be something to evaluate. Manual tuning could be a real challenge.
  • 5. Re: EMC PowerPath Compatibility
    Linux-RAC-Admin Newbie
    Currently Being Moderated
    Thank you everyone! I recieved the4 following information from the EMC community -

    Following Arrays are supported with Powerpath 5.3 SP1 with Oracle Linux[x86_64]: 5.2


    Supported kernels: 2.6.18-92.0.0.0.1.el5, 2.6.18-92.1.1.0.1.el5, 2.6.18-92.1.6.0.2.el5, 2.6.18-92.1.10.0.1.el5, 2.6.18-92.1.13.0.1.el5, 2.6.18-92.1.17.0.1.el5, 2.6.18-92.1.17.0.2.el5;

    2.6.18-92.1.22.0.1.el5. Confirm kernel support with server vendor.




    EMC CLARiiON: CX3-10c, CX3-40c/CX3-20c, CX3-80/CX3-40(F)/CX3-20(F), CX300,

    CX4-120/CX4-240/CX4-480/CX4-960, CX4-120C8/CX4-240C8/CX4-480C8/CX4-960C8,

    CX4-120C8X/CX4-240C8X/CX4-480C8X/CX4-960C8X,

    CX4-120FCOE/CX4-240FCOE/CX4-480FCOE/CX4-960FCOE, CX600/CX400,

    CX700/CX500; EMC Celerra: NS-120 (Native Block), NS-480 (Native Block)24, 25


    EMC Symmetrix: DMX-3, DMX-4, DMX/DMX-2, VMAX, VMAX

    10K (Systems with S/N xxx959xxxx), VMAX 20K, VMAX 40K, VMAXe; EMC Unified Storage

    VNX5100/5300/5500/5700/7500 (Block); NEC Symmetrix: DMX-4, VMAX, VMAX 20K, VMAX 40K

    Since it is our standard to use Power Path with all of our equipment, I will have to maintain that software.
  • 6. Re: EMC PowerPath Compatibility
    898553 Newbie
    Currently Being Moderated
    Dude wrote:
    As far as I know, EMC Powerpath contains optimizations to device fail-over algorithms and I/O performance of specific EMC hardware, at least for MS Windows. I'm not saying that there will necessarily be any performance difference under Linux, but it might be something to evaluate. Manual tuning could be a real challenge.
    When I tested this on both Clariions and Symmetrix arrays on RHEL5 and RHEL6 to do performance comparisons between DM-Multipath, Veritas VxDMP, and PowerPath, PowerPath was consistently about 1-2% faster than DM-Multipath. I can't imagine paying for a 1-2% performance improvement over something that's free.

    Granted, there might be some hidden error handling for EMC arrays but I still don't see it being worth it.
  • 7. Re: EMC PowerPath Compatibility
    Dude! Guru
    Currently Being Moderated
    Seeing other storage solutions and my own experience, the question might even be whether the whole EMC thing is worth it. Protecting an existing investment and setup is not always reasonable and I recommend to check also other vendors to anyone who is starting to invest a lot of money in storage solutions.
  • 8. Re: EMC PowerPath Compatibility
    bobthesungeek76036 Pro
    Currently Being Moderated
    Every EMC shop I have been in it was IT policy to have PowerPath at the host. No questions asked. Arguing about it is futile. Somebody at EMC must be making some very strong kool-aid for sure!
  • 9. Re: EMC PowerPath Compatibility
    BillyVerreynne Oracle ACE
    Currently Being Moderated
    Same here. But then I never had the problem to flatly refuse something that I do not agree with technically.

    So we ceased to use Powerpath over 7 years ago. Have been using multipath since RHEL3, and now on RHEL5/OL5, on everything from Clariion, DMX to VNX SANs. On a number of clusters (currently have 4 RACs at different geo locations, using EMC SANs via multipath).

    Back with RHEL3, ASMLib and Powerpath, there were also a nasty incomptability that resulted in (logical) I/O errors. Also one of the reasons why we also dropped ASMLib all together.

    I want a driver stack that is
    a) Open Source (no tainting the kernel)
    b) with minimal moving parts

    And that is what multipath provides. And other options, like Powerpath, ASMLib, etc, do not.

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