ii(7D)								      Devices								    ii(7D)

NAME

       ii - Instant Image control device

DESCRIPTION

       The ii device is a control interface for Instant Image devices 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) com-
       mand. 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 administration volume must be 8KBytes  +
		  (3 * 8KBytes) =32KBytes in size.

       The  Instant  Image module uses services provided by the SDBC and SD_GEN modules. The SV module is required to present a conventional block
       device interface to the storage product interface of the Instant Image, SDBC and SD_GEN 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 ii_bitmap 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 indicates permanent SDBC storage.  If the system is part of a storage  prod-
       ucts 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.

ATTRIBUTES

       See attributes(5) for a description of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Architecture		     |x86			   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWiu			   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Committed 		   |
       +-----------------------------+-----------------------------+

SEE ALSO

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

SunOS 5.11							    8 Jun 2007								    ii(7D)