MPIO support for SCSI-3 - Storage

This is a discussion on MPIO support for SCSI-3 - Storage ; Hi In "DsmCategorizeRequest" the DSM (Sample DSM from DDK) returns the "DSM_WILL_HANDLE" for SCSI-2 reserve/release/break reservation opcodes. "DsmSrbDeviceControl" then handles the SCSI-2 opcodes. In case if SCSI-3 reservation is sent to DSM ("DsmCategorizeRequest") , it finds the good path to ...

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Thread: MPIO support for SCSI-3

  1. MPIO support for SCSI-3

    Hi

    In "DsmCategorizeRequest" the DSM (Sample DSM from DDK) returns the
    "DSM_WILL_HANDLE" for SCSI-2 reserve/release/break reservation opcodes.
    "DsmSrbDeviceControl" then handles the SCSI-2 opcodes.
    In case if SCSI-3 reservation is sent to DSM ("DsmCategorizeRequest") , it
    finds the good path to send the SCSI-3 request. So I guess if DSM need
    to handle the SCSI-3 commands , then " DsmCategorizeRequest " should return
    the DSM_WILL_HANDLE for SCSI-3 commands as well .

    Please correct me if I am wrong.

    Are there any changes done in MPIO to support SCSI-3 ?

    Thanks
    Santosh



  2. Re: MPIO support for SCSI-3

    RESERVE(6) and RELEASE(6) are SCSI-3 commands defined in SPC-2; they have
    been dropped from the latest version SPC-3 which is still pending approval.
    Clustering only sends RESERVE and RELEASE through IOCTL_STORAGE_RESERVE and
    IOCTL_STORAGE_BREAK_RESERVATION, but in the future (next OS release) will be
    sending PERSISTENT RESERVE IN/OUT (through a new IOCTL interface). The
    requirement will be for DSMs to forward any PRO to each path that is active.
    In some cases, PRO will need to be sent down standby paths, and in any case,
    when a standby path becomes active, the DSM will have to forward the PRO as
    part of the path activation. The MPIO DDK will be updated when that
    information is available.

    3rd party DSMs may choose to convert RESERVE/RELEASE into PRI/PRO to support
    active/active load balancing today. Many of the same concerns wrt
    active/standby paths will apply in this case. The iSCSI DSM does this and
    that sample will be updated in the near future.

    "Santosh" wrote in message
    news:efXJvyDDGHA.1816@TK2MSFTNGP11.phx.gbl...
    > Hi
    >
    > In "DsmCategorizeRequest" the DSM (Sample DSM from DDK) returns the
    > "DSM_WILL_HANDLE" for SCSI-2 reserve/release/break reservation opcodes.
    > "DsmSrbDeviceControl" then handles the SCSI-2 opcodes.
    > In case if SCSI-3 reservation is sent to DSM ("DsmCategorizeRequest") , it
    > finds the good path to send the SCSI-3 request. So I guess if DSM need
    > to handle the SCSI-3 commands , then " DsmCategorizeRequest " should
    > return the DSM_WILL_HANDLE for SCSI-3 commands as well .
    >
    > Please correct me if I am wrong.
    >
    > Are there any changes done in MPIO to support SCSI-3 ?
    >
    > Thanks
    > Santosh
    >




  3. Re: MPIO support for SCSI-3

    Thanks Jeff .

    Regards
    Santosh

    "Jeff Goldner [MS]" wrote in message
    news:%23vCSfCQEGHA.1676@TK2MSFTNGP09.phx.gbl...
    > RESERVE(6) and RELEASE(6) are SCSI-3 commands defined in SPC-2; they have
    > been dropped from the latest version SPC-3 which is still pending
    > approval. Clustering only sends RESERVE and RELEASE through
    > IOCTL_STORAGE_RESERVE and IOCTL_STORAGE_BREAK_RESERVATION, but in the
    > future (next OS release) will be sending PERSISTENT RESERVE IN/OUT
    > (through a new IOCTL interface). The requirement will be for DSMs to
    > forward any PRO to each path that is active. In some cases, PRO will need
    > to be sent down standby paths, and in any case, when a standby path
    > becomes active, the DSM will have to forward the PRO as part of the path
    > activation. The MPIO DDK will be updated when that information is
    > available.
    >
    > 3rd party DSMs may choose to convert RESERVE/RELEASE into PRI/PRO to
    > support active/active load balancing today. Many of the same concerns wrt
    > active/standby paths will apply in this case. The iSCSI DSM does this and
    > that sample will be updated in the near future.
    >
    > "Santosh" wrote in message
    > news:efXJvyDDGHA.1816@TK2MSFTNGP11.phx.gbl...
    >> Hi
    >>
    >> In "DsmCategorizeRequest" the DSM (Sample DSM from DDK) returns the
    >> "DSM_WILL_HANDLE" for SCSI-2 reserve/release/break reservation opcodes.
    >> "DsmSrbDeviceControl" then handles the SCSI-2 opcodes.
    >> In case if SCSI-3 reservation is sent to DSM ("DsmCategorizeRequest") ,
    >> it finds the good path to send the SCSI-3 request. So I guess if DSM
    >> need to handle the SCSI-3 commands , then " DsmCategorizeRequest " should
    >> return the DSM_WILL_HANDLE for SCSI-3 commands as well .
    >>
    >> Please correct me if I am wrong.
    >>
    >> Are there any changes done in MPIO to support SCSI-3 ?
    >>
    >> Thanks
    >> Santosh
    >>

    >
    >




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