Devices                                                    ii(7D)



NAME
     ii - Instant Image control device

DESCRIPTION
     The ii device is a control interface for Instant Image  dev-
     ices  and  controls  the  Instant  Image  module through the
     ioctl(2) interface.


     Instant Image is a point-in-time volume  copy  facility  for
     the  Solaris  operating  environment  that  is  administered
     through the iiadm(1M) command. With Instant Image,  you  can
     create  an  independent  point-in-time copy of a volume or a
     master volume-dependent point-in-time view.   You  can  also
     independently  access  the master and shadow volume for read
     and write operations. Instant Image also lets you update the
     shadow  volume  from the master volume or restore the master
     volume from the shadow. (Restore operations to  volumes  can
     be  full or incremental). Instant Image supports fast volume
     re-synchronization, letting you create a  new  point-in-time
     volume  copy  by  updating  the  specified  volume with only
     changed data.


     To create a shadow volume you need a:

         1.   Master volume to be shadowed.

         2.   Shadow volume where  the  copy  will  reside.  This
              volume  must  be equal to or larger than the master
              volume.

         3.   Administrative bitmap volume or file  for  tracking
              differences  between the shadow and master volumes.
              The administrative bitmap volume or file must be at
              least  24Kbytes  in  size  and requires 8KBytes for
              each GByte (or part thereof) of master volume size,
              plus  an  additional 8KBytes overhead. For example,
              to shadow a 3GByte master volume,  the  administra-
              tion  volume  must  be  8KBytes  ]  (3  *  8KBytes)
              =32KBytes in size.


     The Instant Image module uses services provided by the  SDBC
     and  SDGEN  modules. The SV module is required to present a
     conventional block device interface to the  storage  product
     interface of the Instant Image, SDBC and SDGEN modules.


     When  a  shadow  operation  is  suspended  or  resumed,  the
     administration  volumes  may  be  stored  in  permanent SDBC
     storage or loaded and saved to and from kernel  memory.  The



SunOS 5.11           Last change: 8 Jun 2007                    1






Devices                                                    ii(7D)



     iibitmap  variable in the /kernel/drv/ii.conf configuration
     file determines the administration volume  storage  type.  A
     value of 0 indicates kernel memory, while a value of 1 indi-
     cates permanent SDBC storage.  If the system is  part  of  a
     storage   products  cluster,  use  the  1  value  (permanent
     storage), otherwise use kernel memory (0 value).

FILES
     kernel/drv/ii          32- bit ELF kernel module (x86).


     /kernel/drv/ii.conf    Configuration file.


ATRIBUTES
     See attributes(5) for a description of the following  attri-
     butes:



     
           ATRIBUTE TYPE               ATRIBUTE VALUE       
    
     Architecture                 x86                         
    
     Availability                 SUNWiu                      
    
     Interface Stability          Committed                   
    


SEE ALSO
     iiadm(1M), ioctl(2), attributes(5), sv(7D)






















SunOS 5.11           Last change: 8 Jun 2007                    2