Subject: LZMA compression for lofi [PSARC/2008/785 Self Review]
To:      PSARC-ext@Sun.Com
Cc:      caiman-discuss@opensolaris.org
Bcc:     one-pager-list@sac.sfbay one-pager-log@sac.sfbay sac-bar@sac.sfbay

I am sponsoring the following case for Alok Aggarwal.  Requested
binding is minor, matching the binding for the original lofiadm
compression case (PSARC/2007/569).

This is a straight-forward addition allowing a new compression
algorithm to be used with lofiadm.  I believe this case qualifies as
self-review, and have submitted it as such.  If there is disagreement,
please let me know and I will change it to a regular fast-track.

Template Version: @(#)sac_nextcase %I% %G% SMI
This information is Copyright 2008 Sun Microsystems
1. Introduction
    1.1. Project/Component Working Name:
	 LZMA compression for lofi
    1.2. Name of Document Author/Supplier:
	 Author:  Alok Aggarwal
    1.3  Date of This Document:
	19 December, 2008

4. Technical Description

   This case proposes to add another compression algorithm to the
   list of supported algorithms for lofiadm(1M).

   Currently, lofiadm(1M) allows compression algorithms to be specified
   via the '-C' command line option. gzip-6 and gzip-9 are the two
   supported algorithms. This case intends to add support for LZMA 
   (Lempel-Ziv Markov chain algorithm) as well.  

   Rationale for adding LZMA as a supported algorithm:

   The LZMA algorithm offers distinct advantages in compressing binary
   data, it provides a much higher compression ratio than, say, gzip or bzip2.
   Our testing shows that it compresses between 30-40% better than gzip-9.

   Related CR:

   The work described as part of this case will be delivered with the
   following CR:

   6785864 lzma compression support for lofi
   6785871 lofiadm(1M) should mention lzma as a supported compression algorithm

Command Changes

   The '-C' option to lofiadm(1M) will take an additional optional parameter.
   The changes are as follows -

   SYNOPSIS
   [...]
        /usr/sbin/lofiadm -C algorithm [-s segment_size] file    <----

   [...]
   OPTIONS
   [...]
       -C {gzip | gzip-N | lzma}                                      |

           Compress the file with the specified  compression  algo-   |
	   rithm.                                                     |

	   The gzip compression algorithm uses the same compression
	   as  the  open-source  gzip  command. You can specify the
	   gzip level by using the value gzip-N where N is 6 (fast)
  	   or  9 (best compression ratio). Currently, gzip, without   |
	   a number, is equivalent to gzip-6  (which  is  also  the   |
	   default for the gzip command).

	   lzma stands for the LZMA (Lempel-Ziv-Markov) compression   |
	   algorithm.  

References

   PSARC/2007/569 - lofi(7D) compression support
   http://sac.sfbay/Archives/CaseLog/arc/PSARC/2007/569

   PSARC/1999/463 - lofi
   http://sac.sfbay/Archives/CaseLog/arc/PSARC/1999/463

   LZMA numbers
   http://blogs.sun.com/aalok/entry/lzma_compression

6. Resources and Schedule
    6.4. Steering Committee requested information
   	6.4.1. Consolidation C-team Name:
		ON
    6.5. ARC review type: Automatic
    6.6. ARC Exposure: open