Veritas DMP paths versus native OS paths on Linux - Storage

This is a discussion on Veritas DMP paths versus native OS paths on Linux - Storage ; Hi everybody, I'm experiencing some difficulties in understanding paths on Linux when DMP is in use. Any help will be highly appreciated! below is the result of "vxdisk path" on the server: SUBPATH DANAME DMNAME GROUP STATE sda sda - ...

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Thread: Veritas DMP paths versus native OS paths on Linux

  1. Veritas DMP paths versus native OS paths on Linux

    Hi everybody,

    I'm experiencing some difficulties in understanding paths on Linux
    when DMP is in use.
    Any help will be highly appreciated!

    below is the result of "vxdisk path" on the server:
    SUBPATH DANAME DMNAME
    GROUP STATE
    sda sda -
    - ENABLED

    sdk sdaf scm01 scm
    ENABLED
    sdf sdaf scm01 scm
    ENABLED
    sdaa sdaf scm01 scm
    ENABLED
    sdv sdaf scm01 scm
    ENABLED

    sdai sdah scm04 scm
    ENABLED
    sdak sdah scm04 scm
    ENABLED
    sdaj sdah scm04 scm
    ENABLED
    sdah sdah scm04 scm
    ENABLED

    sdc sde scm02 scm
    ENABLED
    sdh sde scm02 scm
    ENABLED
    sdx sde scm02 scm
    ENABLED
    sds sde scm02 scm
    ENABLED

    sdd sdf scm03 scm
    ENABLED
    sdi sdf scm03 scm
    ENABLED
    sdt sdf scm03 scm
    ENABLED
    sdy sdf scm03 scm
    ENABLED

    sde sdp web1_DG scmweb1
    ENABLED
    sdj sdp web1_DG scmweb1
    ENABLED
    sdu sdp web1_DG scmweb1
    ENABLED
    sdz sdp web1_DG scmweb1
    ENABLED

    sdm sdu -
    - ENABLED
    sdp sdu -
    - ENABLED
    sdac sdu -
    - ENABLED
    sdaf sdu -
    - ENABLED

    sdq sdv -
    - ENABLED
    sdn sdv -
    - ENABLED
    sdag sdv -
    - ENABLED
    sdad sdv -
    - ENABLED


    How is it possible that "sdf" is a sub-path for "sdaf" while it has
    its own sub-paths(sdd, sdi, etc)?
    Similar issue with "sdu".

    Here's the output of vxprint:
    Disk group: scm

    dg scm default default 0 1172451431.7.scm1

    dm scm01 sdaf auto 2048 60763776 -
    dm scm02 sde auto 2048 243062016 -
    dm scm03 sdf auto 2048 243062016 -
    dm scm04 sdah auto 2048 243062016 -

    v app01 - ENABLED ACTIVE 20971520 SELECT
    - fsgen
    pl app01-01 app01 ENABLED ACTIVE 20971520 CONCAT
    - RW
    sd scm02-01 app01-01 scm02 0 20971520 0 sde ENA

    v oa01 - ENABLED ACTIVE 117230800 SELECT
    - fsgen
    pl oa01-01 oa01 ENABLED ACTIVE 117230800 CONCAT
    - RW
    sd scm03-01 oa01-01 scm03 0 33344720 0 sdf ENA
    sd scm04-01 oa01-01 scm04 0 83886080 33344720 sdah ENA

    v od01 - ENABLED ACTIVE 471598336 SELECT
    - fsgen
    pl od01-01 od01 ENABLED ACTIVE 471598336 CONCAT
    - RW
    sd scm02-02 od01-01 scm02 20971520 222090496 0 sde ENA
    sd scm03-05 od01-01 scm03 64802816 178259200 222090496 sdf ENA
    sd scm03-02 od01-01 scm03 33344720 10486576 400349696 sdf ENA
    sd scm04-02 od01-01 scm04 83886080 60762064 410836272 sdah ENA

    v or01 - ENABLED ACTIVE 10485760 SELECT
    - fsgen
    pl or01-01 or01 ENABLED ACTIVE 10485760 CONCAT
    - RW
    sd scm03-03 or01-01 scm03 43831296 10485760 0 sdf ENA

    v or02 - ENABLED ACTIVE 10485760 SELECT
    - fsgen
    pl or02-01 or02 ENABLED ACTIVE 10485760 CONCAT
    - RW
    sd scm03-04 or02-01 scm03 54317056 10485760 0 sdf ENA

    Disk group: scmweb1

    dg scmweb1 default default 0 1203605677.19.scm1

    dm web1_DG sdp auto 2048 243062016 -

    v app01 - ENABLED ACTIVE 20971520 SELECT
    - fsgen
    pl app01-01 app01 ENABLED ACTIVE 20971520 CONCAT
    - RW
    sd web1_DG-04 app01-01 web1_DG 104857600 20971520 0
    sdp ENA

    v oa01 - ENABLED ACTIVE 117231616 SELECT
    - fsgen
    pl oa01-01 oa01 ENABLED ACTIVE 117231616 CONCAT
    - RW
    sd web1_DG-05 oa01-01 web1_DG 125829120 117231616 0
    sdp ENA

    v od01 - ENABLED ACTIVE 83886080 SELECT
    - fsgen
    pl od01-01 od01 ENABLED ACTIVE 83886080 CONCAT
    - RW
    sd web1_DG-01 od01-01 web1_DG 0 83886080 0
    sdp ENA

    v or01 - ENABLED ACTIVE 10485760 SELECT
    - fsgen
    pl or01-01 or01 ENABLED ACTIVE 10485760 CONCAT
    - RW
    sd web1_DG-02 or01-01 web1_DG 83886080 10485760 0
    sdp ENA

    v or02 - ENABLED ACTIVE 10485760 SELECT
    - fsgen
    pl or02-01 or02 ENABLED ACTIVE 10485760 CONCAT
    - RW
    sd web1_DG-03 or02-01 web1_DG 94371840 10485760 0
    sdp ENA


    Note that according to this, two volume groups on the same server have
    a shared disk, which of course makes no sense.

    Here's the output of EMC's inq:
    ----------------------------------------------------------------------------
    Symmetrix Device Symm Serial # Device # WWN
    ----------------------------------------------------------------------------
    /dev/sdb 000287864825 0291A
    60060480000287864825533032393141
    /dev/sdc 000287864825 00640
    6006048000028786482553594d363430
    /dev/sdd 000287864825 00644
    6006048000028786482553594d363434
    /dev/sde 000287864825 0035C
    6006048000028786482553594d333543
    /dev/sdf 000287864825 023E4
    60060480000287864825533032334534
    /dev/sdg 000287864825 0291A
    60060480000287864825533032393141
    /dev/sdh 000287864825 00640
    6006048000028786482553594d363430
    /dev/sdi 000287864825 00644
    6006048000028786482553594d363434
    /dev/sdj 000287864825 0035C
    6006048000028786482553594d333543
    /dev/sdk 000287864825 023E4
    60060480000287864825533032334534
    /dev/sdl 000290133814 00FDF
    60060480000290133814533030464446
    /dev/sdm 000290133814 003C0
    60060480000290133814533030334330
    /dev/sdn 000290133814 00A5F
    60060480000290133814533030413546
    /dev/sdo 000290133814 00FDF
    60060480000290133814533030464446
    /dev/sdp 000290133814 003C0
    60060480000290133814533030334330
    /dev/sdq 000290133814 00A5F
    60060480000290133814533030413546
    /dev/sdr 000287864825 0291A
    60060480000287864825533032393141
    /dev/sds 000287864825 00640
    6006048000028786482553594d363430
    /dev/sdt 000287864825 00644
    6006048000028786482553594d363434
    /dev/sdu 000287864825 0035C
    6006048000028786482553594d333543
    /dev/sdv 000287864825 023E4
    60060480000287864825533032334534
    /dev/sdw 000287864825 0291A
    60060480000287864825533032393141
    /dev/sdx 000287864825 00640
    6006048000028786482553594d363430
    /dev/sdy 000287864825 00644
    6006048000028786482553594d363434
    /dev/sdz 000287864825 0035C
    6006048000028786482553594d333543
    /dev/sdaa 000287864825 023E4
    60060480000287864825533032334534
    /dev/sdab 000290133814 00FDF
    60060480000290133814533030464446
    /dev/sdac 000290133814 003C0
    60060480000290133814533030334330
    /dev/sdad 000290133814 00A5F
    60060480000290133814533030413546
    /dev/sdae 000290133814 00FDF
    60060480000290133814533030464446
    /dev/sdaf 000290133814 003C0
    60060480000290133814533030334330
    /dev/sdag 000290133814 00A5F
    60060480000290133814533030413546
    /dev/sdah 000287864825 0021C
    6006048000028786482553594d323143
    /dev/sdai 000287864825 0021C
    6006048000028786482553594d323143
    /dev/sdaj 000287864825 0021C
    6006048000028786482553594d323143
    /dev/sdak 000287864825 0021C
    6006048000028786482553594d323143
    /dev/vx/rdmp/sde 000287864825 00640
    6006048000028786482553594d363430
    /dev/vx/rdmp/sdf 000287864825 00644
    6006048000028786482553594d363434
    /dev/vx/rdmp/sdp 000287864825 0035C
    6006048000028786482553594d333543
    /dev/vx/rdmp/sdu 000290133814 003C0
    60060480000290133814533030334330
    /dev/vx/rdmp/sdv 000290133814 00A5F
    60060480000290133814533030413546
    /dev/vx/rdmp/sdaf 000287864825 023E4
    60060480000287864825533032334534
    /dev/vx/rdmp/sdah 000287864825 0021C
    6006048000028786482553594d323143



    The only explanation I could think of is that /dev/XYZ and /dev/vx/
    rdmp/XYZ do not refer to the same device.
    I'm quite sure that on HPUX, solaris and AIX /dev/rdsk/XYZ and /dev/vx/
    rdmp/XYZ do lead to the same storage device.
    Is it different on Linux?


    Thanks,
    David

  2. Re: Veritas DMP paths versus native OS paths on Linux

    David,
    You are missing the output from a key command: vxdisk list, and it
    looks like your inq terminated prematurely (or was edited?). Execute
    vxdisk list against a single VX volume and you should see a value
    called "numpaths" and the paths to the physical disks, too. Remember
    that Veritas creates a virtual volume that lays on top of the physical
    volume/path. The OS talks to the Veritas virtual volume and Veritas
    manages the paths under it. For example, the OS sends IO to /dev/vx/
    rdmp/sdab and Veritas will manage the IO between physical paths /dev/
    sdb1 and /dev/sdr1 (both paths to your symvol 0291A). I didn't see
    the inq output listing the Veritas volume that pointed to 0291A so I
    assume you truncated the output.

    Typically you should see (3) lines of information for each masked
    symvol from inq: one from each path, and the Veritas virtual device.

    After a 2nd look at your inq, I'm curious ... how many HBA's do you
    have on the server? And how many masks do you have to each HBA for a
    symvol?

    Marv

    p.s. add the operand "-showvol" to your inq and it will clean things
    up a little, and split the symvol into a separate column, too.

    On Aug 6, 12:21 pm, val...@gmail.com wrote:
    > Hi everybody,
    >
    > I'm experiencing some difficulties in understanding paths on Linux
    > when DMP is in use.
    > Any help will be highly appreciated!
    >
    > below is the result of "vxdisk path" on the server:
    > SUBPATH DANAME DMNAME
    > GROUP STATE
    > sda sda -
    > - ENABLED
    >
    > sdk sdaf scm01 scm
    > ENABLED
    > sdf sdaf scm01 scm
    > ENABLED
    > sdaa sdaf scm01 scm
    > ENABLED
    > sdv sdaf scm01 scm
    > ENABLED
    >
    > sdai sdah scm04 scm
    > ENABLED
    > sdak sdah scm04 scm
    > ENABLED
    > sdaj sdah scm04 scm
    > ENABLED
    > sdah sdah scm04 scm
    > ENABLED
    >
    > sdc sde scm02 scm
    > ENABLED
    > sdh sde scm02 scm
    > ENABLED
    > sdx sde scm02 scm
    > ENABLED
    > sds sde scm02 scm
    > ENABLED
    >
    > sdd sdf scm03 scm
    > ENABLED
    > sdi sdf scm03 scm
    > ENABLED
    > sdt sdf scm03 scm
    > ENABLED
    > sdy sdf scm03 scm
    > ENABLED
    >
    > sde sdp web1_DG scmweb1
    > ENABLED
    > sdj sdp web1_DG scmweb1
    > ENABLED
    > sdu sdp web1_DG scmweb1
    > ENABLED
    > sdz sdp web1_DG scmweb1
    > ENABLED
    >
    > sdm sdu -
    > - ENABLED
    > sdp sdu -
    > - ENABLED
    > sdac sdu -
    > - ENABLED
    > sdaf sdu -
    > - ENABLED
    >
    > sdq sdv -
    > - ENABLED
    > sdn sdv -
    > - ENABLED
    > sdag sdv -
    > - ENABLED
    > sdad sdv -
    > - ENABLED
    >
    > How is it possible that "sdf" is a sub-path for "sdaf" while it has
    > its own sub-paths(sdd, sdi, etc)?
    > Similar issue with "sdu".
    >
    > Here's the output of vxprint:
    > Disk group: scm
    >
    > dg scm default default 0 1172451431.7.scm1
    >
    > dm scm01 sdaf auto 2048 60763776 -
    > dm scm02 sde auto 2048 243062016 -
    > dm scm03 sdf auto 2048 243062016 -
    > dm scm04 sdah auto 2048 243062016 -
    >
    > v app01 - ENABLED ACTIVE 20971520 SELECT
    > - fsgen
    > pl app01-01 app01 ENABLED ACTIVE 20971520 CONCAT
    > - RW
    > sd scm02-01 app01-01 scm02 0 20971520 0 sde ENA
    >
    > v oa01 - ENABLED ACTIVE 117230800 SELECT
    > - fsgen
    > pl oa01-01 oa01 ENABLED ACTIVE 117230800 CONCAT
    > - RW
    > sd scm03-01 oa01-01 scm03 0 33344720 0 sdf ENA
    > sd scm04-01 oa01-01 scm04 0 83886080 33344720 sdah ENA
    >
    > v od01 - ENABLED ACTIVE 471598336 SELECT
    > - fsgen
    > pl od01-01 od01 ENABLED ACTIVE 471598336 CONCAT
    > - RW
    > sd scm02-02 od01-01 scm02 20971520 222090496 0 sde ENA
    > sd scm03-05 od01-01 scm03 64802816 178259200 222090496 sdf ENA
    > sd scm03-02 od01-01 scm03 33344720 10486576 400349696 sdf ENA
    > sd scm04-02 od01-01 scm04 83886080 60762064 410836272 sdah ENA
    >
    > v or01 - ENABLED ACTIVE 10485760 SELECT
    > - fsgen
    > pl or01-01 or01 ENABLED ACTIVE 10485760 CONCAT
    > - RW
    > sd scm03-03 or01-01 scm03 43831296 10485760 0 sdf ENA
    >
    > v or02 - ENABLED ACTIVE 10485760 SELECT
    > - fsgen
    > pl or02-01 or02 ENABLED ACTIVE 10485760 CONCAT
    > - RW
    > sd scm03-04 or02-01 scm03 54317056 10485760 0 sdf ENA
    >
    > Disk group: scmweb1
    >
    > dg scmweb1 default default 0 1203605677.19.scm1
    >
    > dm web1_DG sdp auto 2048 243062016 -
    >
    > v app01 - ENABLED ACTIVE 20971520 SELECT
    > - fsgen
    > pl app01-01 app01 ENABLED ACTIVE 20971520 CONCAT
    > - RW
    > sd web1_DG-04 app01-01 web1_DG 104857600 20971520 0
    > sdp ENA
    >
    > v oa01 - ENABLED ACTIVE 117231616 SELECT
    > - fsgen
    > pl oa01-01 oa01 ENABLED ACTIVE 117231616 CONCAT
    > - RW
    > sd web1_DG-05 oa01-01 web1_DG 125829120 117231616 0
    > sdp ENA
    >
    > v od01 - ENABLED ACTIVE 83886080 SELECT
    > - fsgen
    > pl od01-01 od01 ENABLED ACTIVE 83886080 CONCAT
    > - RW
    > sd web1_DG-01 od01-01 web1_DG 0 83886080 0
    > sdp ENA
    >
    > v or01 - ENABLED ACTIVE 10485760 SELECT
    > - fsgen
    > pl or01-01 or01 ENABLED ACTIVE 10485760 CONCAT
    > - RW
    > sd web1_DG-02 or01-01 web1_DG 83886080 10485760 0
    > sdp ENA
    >
    > v or02 - ENABLED ACTIVE 10485760 SELECT
    > - fsgen
    > pl or02-01 or02 ENABLED ACTIVE 10485760 CONCAT
    > - RW
    > sd web1_DG-03 or02-01 web1_DG 94371840 10485760 0
    > sdp ENA
    >
    > Note that according to this, two volume groups on the same server have
    > a shared disk, which of course makes no sense.
    >
    > Here's the output of EMC's inq:
    > ----------------------------------------------------------------------------
    > Symmetrix Device Symm Serial # Device # WWN
    > ----------------------------------------------------------------------------
    > /dev/sdb 000287864825 0291A
    > 60060480000287864825533032393141
    > /dev/sdc 000287864825 00640
    > 6006048000028786482553594d363430
    > /dev/sdd 000287864825 00644
    > 6006048000028786482553594d363434
    > /dev/sde 000287864825 0035C
    > 6006048000028786482553594d333543
    > /dev/sdf 000287864825 023E4
    > 60060480000287864825533032334534
    > /dev/sdg 000287864825 0291A
    > 60060480000287864825533032393141
    > /dev/sdh 000287864825 00640
    > 6006048000028786482553594d363430
    > /dev/sdi 000287864825 00644
    > 6006048000028786482553594d363434
    > /dev/sdj 000287864825 0035C
    > 6006048000028786482553594d333543
    > /dev/sdk 000287864825 023E4
    > 60060480000287864825533032334534
    > /dev/sdl 000290133814 00FDF
    > 60060480000290133814533030464446
    > /dev/sdm 000290133814 003C0
    > 60060480000290133814533030334330
    > /dev/sdn 000290133814 00A5F
    > 60060480000290133814533030413546
    > /dev/sdo 000290133814 00FDF
    > 60060480000290133814533030464446
    > /dev/sdp 000290133814 003C0
    > 60060480000290133814533030334330
    > /dev/sdq 000290133814 00A5F
    > 60060480000290133814533030413546
    > /dev/sdr 000287864825 0291A
    > 60060480000287864825533032393141
    > /dev/sds 000287864825 00640
    > 6006048000028786482553594d363430
    > /dev/sdt 000287864825 00644
    > 6006048000028786482553594d363434
    > /dev/sdu 000287864825 0035C
    > 6006048000028786482553594d333543
    > /dev/sdv 000287864825 023E4
    > 60060480000287864825533032334534
    > /dev/sdw 000287864825 0291A
    > 60060480000287864825533032393141
    > /dev/sdx 000287864825 00640
    > 6006048000028786482553594d363430
    > /dev/sdy 000287864825 00644
    > 6006048000028786482553594d363434
    > /dev/sdz 000287864825 0035C
    > 6006048000028786482553594d333543
    > /dev/sdaa 000287864825 023E4
    > 60060480000287864825533032334534
    > /dev/sdab 000290133814 00FDF
    > 60060480000290133814533030464446
    > /dev/sdac 000290133814 003C0
    > 60060480000290133814533030334330
    > /dev/sdad 000290133814 00A5F
    > 60060480000290133814533030413546
    > /dev/sdae 000290133814 00FDF
    > 60060480000290133814533030464446
    > /dev/sdaf 000290133814 003C0
    > 60060480000290133814533030334330
    > /dev/sdag 000290133814 00A5F
    > 60060480000290133814533030413546
    > /dev/sdah 000287864825 0021C
    > 6006048000028786482553594d323143
    > /dev/sdai 000287864825 0021C
    > 6006048000028786482553594d323143
    > /dev/sdaj 000287864825 0021C
    > 6006048000028786482553594d323143
    > /dev/sdak 000287864825 0021C
    > 6006048000028786482553594d323143
    > /dev/vx/rdmp/sde 000287864825 00640
    > 6006048000028786482553594d363430
    > /dev/vx/rdmp/sdf 000287864825 00644
    > 6006048000028786482553594d363434
    > /dev/vx/rdmp/sdp 000287864825 0035C
    > 6006048000028786482553594d333543
    > /dev/vx/rdmp/sdu 000290133814 003C0
    > 60060480000290133814533030334330
    > /dev/vx/rdmp/sdv 000290133814 00A5F
    > 60060480000290133814533030413546
    > /dev/vx/rdmp/sdaf 000287864825 023E4
    > 60060480000287864825533032334534
    > /dev/vx/rdmp/sdah 000287864825 0021C
    > 6006048000028786482553594d323143
    >
    > The only explanation I could think of is that /dev/XYZ and /dev/vx/
    > rdmp/XYZ do not refer to the same device.
    > I'm quite sure that on HPUX, solaris and AIX /dev/rdsk/XYZ and /dev/vx/
    > rdmp/XYZ do lead to the same storage device.
    > Is it different on Linux?
    >
    > Thanks,
    > David



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