How to make striped volume > 1 TB - Veritas Volume Manager

This is a discussion on How to make striped volume > 1 TB - Veritas Volume Manager ; I am trying to stripe 36 50GB disks to make a 1.75TB volume. However, SEVM 2.6 Solaris 2.6 will only let me create one with 22 disks to make a 1.07TB volume. If I try to create one with 23 ...

+ Reply to Thread
Results 1 to 4 of 4

Thread: How to make striped volume > 1 TB

  1. How to make striped volume > 1 TB


    I am trying to stripe 36 50GB disks to make a 1.75TB
    volume. However, SEVM 2.6 Solaris 2.6 will only let
    me create one with 22 disks to make a 1.07TB volume.
    If I try to create one with 23 disks, I get errors.

  2. Re: How to make striped volume > 1 TB

    Phil Lu wrote:
    >
    > I am trying to stripe 36 50GB disks to make a 1.75TB
    > volume. However, SEVM 2.6 Solaris 2.6 will only let
    > me create one with 22 disks to make a 1.07TB volume.
    > If I try to create one with 23 disks, I get errors.


    From man vxintro:

    The Volume Manager supports volume lengths up to
    2,147,483,647 disk sectors (one terabyte on most systems).

    --
    Charles Jardine - Computing Service, University of Cambridge
    cj10@cam.ac.uk Tel: +44 1223 334506, Fax: +44 1223 334679

  3. Re: How to make striped volume > 1 TB


    Charles Jardine wrote:
    >Phil Lu wrote:
    >>
    >> I am trying to stripe 36 50GB disks to make a 1.75TB
    >> volume. However, SEVM 2.6 Solaris 2.6 will only let
    >> me create one with 22 disks to make a 1.07TB volume.
    >> If I try to create one with 23 disks, I get errors.

    >
    >From man vxintro:
    >
    >The Volume Manager supports volume lengths up to
    >2,147,483,647 disk sectors (one terabyte on most systems).
    >
    >--
    >Charles Jardine - Computing Service, University of Cambridge
    >cj10@cam.ac.uk Tel: +44 1223 334506, Fax: +44 1223 334679


    I read from Richard McDougall's "Getting to know the Solaris
    filesystem" that veritas supports filesystems up to 8,000 TB
    (2^63 bytes). Is he mistaken? Is there veritas documentation
    that delineates all limitations?

    Is there a way to tell your system to use 8192 byte disk sectors
    instead of 512?

    Notice that both invocations below use a volume length lower
    than the man vxintro limit.

    ====== Output of ERROR with 23 disks ==========================
    Executing: '/usr/sbin/vxassist -g 2 -U fsgen -p maxsize layout=stripe,nolog
    nstripe=23 stripeunit=4096'.
    2147481600
    Expected: 0. Return Code: 0.
    ---- Making Volume ...
    Executing: '/usr/sbin/vxassist -g 2 -U fsgen make v2 2147481600
    layout=stripe,nolog nstripe=23 stripeunit=4096'.
    Error: (exp=0!=24): Executing '/usr/sbin/vxassist -g 2 -U fsgen make v2
    2147481600 layout=stripe,nolog nstripe=23 stripeunit=4096':
    vxvm:vxvol: ERROR: Volume v2 has no associated data plexes
    vxvm:vxassist: ERROR: Could not initialize volume v2
    Expected: 0. Return Code: 24.
    ====== Output of SUCCESS with 22 disks ========================
    Executing: '/usr/sbin/vxassist -g 2 -U fsgen -p maxsize layout=stripe,nolog
    nstripe=22 stripeunit=4096'.
    2146828288
    Expected: 0. Return Code: 0.
    ---- Making Volume ...
    Executing: '/usr/sbin/vxassist -g 2 -U fsgen make v2 2146828288
    layout=stripe,nolog nstripe=22 stripeunit=4096'.
    Expected: 0. Return Code: 0.


  4. Re: How to make striped volume > 1 TB

    Phil Lu wrote:
    >
    > Charles Jardine wrote:
    > >Phil Lu wrote:
    > >>
    > >> I am trying to stripe 36 50GB disks to make a 1.75TB
    > >> volume. However, SEVM 2.6 Solaris 2.6 will only let
    > >> me create one with 22 disks to make a 1.07TB volume.
    > >> If I try to create one with 23 disks, I get errors.

    > >
    > >From man vxintro:
    > >
    > >The Volume Manager supports volume lengths up to
    > >2,147,483,647 disk sectors (one terabyte on most systems).
    > >

    > I read from Richard McDougall's "Getting to know the Solaris
    > filesystem" that veritas supports filesystems up to 8,000 TB
    > (2^63 bytes). Is he mistaken?


    I expect that this is intended to refer to the Verites File System,
    which uses 64-bit arithmetic. The Volume Manager is a different
    matter.

    > Is there a way to tell your system to use 8192 byte disk sectors
    > instead of 512?


    I think not. This is a property of the disc hardware.

    >
    > Notice that both invocations below use a volume length lower
    > than the man vxintro limit.
    >
    > ====== Output of ERROR with 23 disks ==========================
    > Executing: '/usr/sbin/vxassist -g 2 -U fsgen -p maxsize layout=stripe,nolog
    > nstripe=23 stripeunit=4096'.
    > 2147481600
    > Expected: 0. Return Code: 0.


    This has clearly given the wrong answer. 2147481600 is not divisible
    by 23. Since 22 stripes gives 2146828288 sectors, one would expect
    23 stripes to give 2244411392 sectors, which exceeds the limit.

    I expect you have provoked a bug in vxassist, by asking it to
    solve a problem which overflows in 32 bit arithmetic.

    --
    Charles Jardine - Computing Service, University of Cambridge
    cj10@cam.ac.uk Tel: +44 1223 334506, Fax: +44 1223 334679

+ Reply to Thread