raid5 problem - Veritas Volume Manager

This is a discussion on raid5 problem - Veritas Volume Manager ; I have 6 9GB (45G total) drives in a D1000 attached to an Ultra250. Can someone explain why when I ask for a maxsize of raid5 I can only have a 17gb volume? See below for all the maxsize answers. ...

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Thread: raid5 problem

  1. raid5 problem

    I have 6 9GB (45G total) drives in a D1000 attached to an Ultra250. Can
    someone explain why when I ask for a maxsize of raid5 I can only have a
    17gb volume? See below for all the maxsize answers. I would have
    thought I'd be able to have a bigger volume than the mirrored volume.

    I'm using volume manager 2.6

    # uname -a
    SunOS dreamer 5.6 Generic_105181-19 sun4u sparc SUNW,Ultra-250

    # vxdg free
    GROUP DISK DEVICE TAG OFFSET LENGTH
    FLAGS

    homedg homedg01 c1t0d0s2 c1t0d0 0 17678493
    -
    homedg homedg02 c1t10d0s2 c1t10d0 0 17678493
    -
    homedg homedg03 c1t1d0s2 c1t1d0 0 17678493
    -
    homedg homedg04 c1t2d0s2 c1t2d0 0 17678493
    -
    homedg homedg05 c1t8d0s2 c1t8d0 0 17678493
    -
    homedg homedg06 c1t9d0s2 c1t9d0 0 17678493
    -

    # vxassist -g homedg maxsize layout=raid5
    Maximum volume size: 35356672 (17264Mb)

    # vxassist -g homedg maxsize layout=mirror
    Maximum volume size: 53035008 (25896Mb)

    # vxassist -g homedg maxsize layout=stripe
    Maximum volume size: 106070016 (51792Mb)

    thanks in advance for any help.
    claudia


  2. Re: raid5 problem


    Perhaps previously the mirror all volumes option was used. In
    that case the nmirror=1 attribute would have to be added.

    Claudia Miller wrote:
    >I have 6 9GB (45G total) drives in a D1000 attached to an Ultra250. Can
    >someone explain why when I ask for a maxsize of raid5 I can only have a
    >17gb volume? See below for all the maxsize answers. I would have
    >thought I'd be able to have a bigger volume than the mirrored volume.
    >
    >I'm using volume manager 2.6
    >
    ># uname -a
    >SunOS dreamer 5.6 Generic_105181-19 sun4u sparc SUNW,Ultra-250
    >
    ># vxdg free
    >GROUP DISK DEVICE TAG OFFSET LENGTH
    >FLAGS
    >
    >homedg homedg01 c1t0d0s2 c1t0d0 0 17678493
    >-
    >homedg homedg02 c1t10d0s2 c1t10d0 0 17678493
    >-
    >homedg homedg03 c1t1d0s2 c1t1d0 0 17678493
    >-
    >homedg homedg04 c1t2d0s2 c1t2d0 0 17678493
    >-
    >homedg homedg05 c1t8d0s2 c1t8d0 0 17678493
    >-
    >homedg homedg06 c1t9d0s2 c1t9d0 0 17678493
    >-
    >
    ># vxassist -g homedg maxsize layout=raid5
    >Maximum volume size: 35356672 (17264Mb)
    >
    ># vxassist -g homedg maxsize layout=mirror
    >Maximum volume size: 53035008 (25896Mb)
    >
    ># vxassist -g homedg maxsize layout=stripe
    >Maximum volume size: 106070016 (51792Mb)
    >
    >thanks in advance for any help.
    >claudia
    >



  3. Re: raid5 problem

    I figured out that the default columns is 3 and I wanted to use 5 disks
    (which I think are the same as columns)
    I ended up using the gui and choosing 5 columns and chose no log. when I
    selected to have a log I lost disk space and it seems you need to allocate a
    whole disk to logging and I can't afford to waste a whole 9gb disk on
    logging...
    If anyone know a way around this I'd appreciate hearing about it. I tried
    to run

    dreamer21:vxassist -g homedg addlog home01
    vxvm:vxassist: ERROR: Cannot allocate space for 1600 block log

    but it seems I should have had enough room for it.

    dreamer23:vxdg -g homedg free
    DISK DEVICE TAG OFFSET LENGTH FLAGS
    homedg01 c1t0d0s2 c1t0d0 17154207 524286 -
    homedg02 c1t10d0s2 c1t10d0 17154207 524286 -
    homedg03 c1t1d0s2 c1t1d0 17154207 524286 -
    homedg04 c1t2d0s2 c1t2d0 17154207 524286 -
    homedg05 c1t8d0s2 c1t8d0 17154207 524286 -

    thanks for any help,
    claudia

    Claudia Miller wrote:

    > I have 6 9GB (45G total) drives in a D1000 attached to an Ultra250. Can
    > someone explain why when I ask for a maxsize of raid5 I can only have a
    > 17gb volume? See below for all the maxsize answers. I would have
    > thought I'd be able to have a bigger volume than the mirrored volume.
    >
    > I'm using volume manager 2.6
    >
    > # uname -a
    > SunOS dreamer 5.6 Generic_105181-19 sun4u sparc SUNW,Ultra-250
    >
    > # vxdg free
    > GROUP DISK DEVICE TAG OFFSET LENGTH
    > FLAGS
    >
    > homedg homedg01 c1t0d0s2 c1t0d0 0 17678493
    > -
    > homedg homedg02 c1t10d0s2 c1t10d0 0 17678493
    > -
    > homedg homedg03 c1t1d0s2 c1t1d0 0 17678493
    > -
    > homedg homedg04 c1t2d0s2 c1t2d0 0 17678493
    > -
    > homedg homedg05 c1t8d0s2 c1t8d0 0 17678493
    > -
    > homedg homedg06 c1t9d0s2 c1t9d0 0 17678493
    > -
    >
    > # vxassist -g homedg maxsize layout=raid5
    > Maximum volume size: 35356672 (17264Mb)
    >
    > # vxassist -g homedg maxsize layout=mirror
    > Maximum volume size: 53035008 (25896Mb)
    >
    > # vxassist -g homedg maxsize layout=stripe
    > Maximum volume size: 106070016 (51792Mb)
    >
    > thanks in advance for any help.
    > claudia



  4. Re: raid5 problem

    Claudia Miller wrote:
    [...]
    > I ended up using the gui and choosing 5 columns and chose no log. when I
    > selected to have a log I lost disk space and it seems you need to allocate a
    > whole disk to logging and I can't afford to waste a whole 9gb disk on
    > logging...


    just as every other slice in a RAID5, the log has to be on a seperate
    physical disk. if you only have one volume, this means using a whole
    disk.

    -mike

    --
    Thomas 'Mike' Michlmayr | "it's the end of the world as we
    | know it, and i feel fine." REM

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