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IdaWong's avatar
IdaWong
Level 4
11 years ago

would vxvm mirroring activities take lower priority than normal write activity before it is synced up?

hi,

I have a question here, hoping someone could point out perhaps.

is a vxvm mirroring event (before it is sync-ed up) takes lower priority than a normal I/O data write?

the reason I am asking is because if during vxvm mirror setup, would it slow down normal data I/O

it would make sense to lower the priority of these writes than normal data I/O I would think.

thanks in advance.

  • See extract from 6.0 release notes:

    Veritas Volume Manager throttling of administrative I/O
     

    In this release, Veritas Volume Manager (VxVM) provides throttling of
    administrative I/O. During heavy I/O loads, VxVM throttles I/O that it creates to
    do administrative operations. This behavior ensures that the administrative I/Os
    do not affect the application I/O performance. When the application I/O load is
    lighter, VxVM increases the bandwidth usage for administrative I/O operations.
    VxVM automatically manages the I/O throttling for administrative tasks, based
    on its perceived load on the storage. Currently, I/O throttling is supported for the
    copy operations which use ATOMIC_COPY and involve one destination mirror.
    The I/O throttling is transparent, and does not change the command usage or
    output. The following commands are supported:
    ■ vxassist mirror
    ■ vxassist snapcreate
    ■ vxevac
    ■ vxplex att
    ■ vxplex cp
    ■ vxplex mv
    ■ vxprint
    ■ vxsnap addmir
    ■ vxsnap reattach
    ■ vxsd mv
    ■ vxtune
    The administrative I/O operations allocate memory for I/O from a separate memory
    pool. You can tune the maximum size of this pool with the tunable parameter,
    vol_max_adminio_poolsz .
    See the Veritas Storage Foundation Tuning Guide for information about tuning
    the vol_max_adminio_poolsz parameter.

     

    Mike

  • See extract from 6.0 release notes:

    Veritas Volume Manager throttling of administrative I/O
     

    In this release, Veritas Volume Manager (VxVM) provides throttling of
    administrative I/O. During heavy I/O loads, VxVM throttles I/O that it creates to
    do administrative operations. This behavior ensures that the administrative I/Os
    do not affect the application I/O performance. When the application I/O load is
    lighter, VxVM increases the bandwidth usage for administrative I/O operations.
    VxVM automatically manages the I/O throttling for administrative tasks, based
    on its perceived load on the storage. Currently, I/O throttling is supported for the
    copy operations which use ATOMIC_COPY and involve one destination mirror.
    The I/O throttling is transparent, and does not change the command usage or
    output. The following commands are supported:
    ■ vxassist mirror
    ■ vxassist snapcreate
    ■ vxevac
    ■ vxplex att
    ■ vxplex cp
    ■ vxplex mv
    ■ vxprint
    ■ vxsnap addmir
    ■ vxsnap reattach
    ■ vxsd mv
    ■ vxtune
    The administrative I/O operations allocate memory for I/O from a separate memory
    pool. You can tune the maximum size of this pool with the tunable parameter,
    vol_max_adminio_poolsz .
    See the Veritas Storage Foundation Tuning Guide for information about tuning
    the vol_max_adminio_poolsz parameter.

     

    Mike