Investor Business Presentation by xyd32971

VIEWS: 16 PAGES: 9

									Should FAIS be DPC Aware?


      Zulfiqar Qazilbash & Mark Ish
                 iVivity




          The Intelligent Convergence of Storage and Networking
                                                  Pg 2
            Should FAIS be DPC aware?


FAIS should support two classes of DPC
  A DPC can be “intelligent ” or “passive ”:

   Passive: provides no IO assists to CPP or SA
   Intelligent: definition next page




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            What is an “intelligent” DPC?

  A DPC is “intelligent” if it can:
      Offload certain IO operations
      Can manage certain rudimentary control functions
      without CPP intervention
      Somewhat conceptually similar to “processor” class
      device class in SCSI
      Does not replace CPP




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                                                 Pg 4
            Why Intelligent DPC?

  Communications between DPC & CPC are
  expensive and should be minimized
  Data should never be sent back to CPC - only
  exceptions
  Asynchronous notification between DPC &
  CPC would allow for maximum performance
  Error recovery is better performed closer to
  the devices



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                                                   Pg 5
            Why Intelligent DPC?

  Data replication/reconstruction is better
  performed closer to the devices
  Flow control is better performed closer to the
  devices
  Device discovery and recovery is better
  performed closer to the devices
  I/O Maps should be extensive enough to
  allow DPC terminate and re-issue any type of
  I/O including boundary conditions


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                                                     Pg 6
An intelligent DPC can assist CPC/SA in many areas



       Offload network & device discovery
       Boost IOPS performance
       Offload IO operations/application data path
       Fault tolerance/error handling/HA
       IO/device statistics/Data logging

       Comprehensive reference framework in iVivity
       VAAPI (submitted to FAIS earlier)

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                                                                     Pg 7
Example Function for Discovery of DPC Capabilities

  int GetDPCCapabilities(Address, size of allocated memory);
  Where Address is a pointer to a structure for the return values;
  Where Size is the size of allocated memory for that structure;
  Return value 0 indicates success, with –1 indicating error;

  The sample structure can be something like {
    Byte ErrorLevel;        /* 0 – none … 5 – complete */
    Byte DeviceProtection; /* 0–none, 1–mirror … 5 – P+Q parity*/
    Byte MultiPath;          /* 0 – No, 1 – Yes */
    Byte DeviceDiscovery; /* 0 – No, 1 – Yes */
    Byte DeviceRecovery; /* 0 – No, 1 – Yes */
    Byte FlowControl;      /* 0 – None, 1 – some … 5 – Full */
    HalfWord Reserved;
    Word IOMapSize; /* 0 – None, -1 – Unlimited; otherwise KB */
  }

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                                                                 Pg 8
 Example Function for Setting of DPC Capabilities



int SetDPCCapabilities{Address, size);
Where Address is a structure of capabilities described in
previous slide
Where size is the size in bytes of that structure
Return 0 signifies success, with –1 signifying failure
Setting any value to 0 will turn that capability off. DPC will
bump the request to CPC for these functions.




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                                                     Pg 9
              Recommendations

 FAIS should support both “intelligent” as well as
 “passive” DPC implementations
 VAAPI can be used as a reference framework to
 create proposal for FAIS phase 1 capability



 Can be one vendor proposal -or-
 from a sub group with representation from other
 interested DPC vendor, ISV and system companies



12/2/2003           RESTRICTED AND CONFIDENTIAL

								
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