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Conference ssag::save_set_manager

Title:Save Set Manager
Moderator:SSAG::SUSSWEIN
Created:Tue Nov 15 1994
Last Modified:Wed May 28 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:72
Total number of notes:276

67.0. "Another Question" by NQOS01::a-113.tunnel.crl.dec.com::ohfss1.ohf.dec.com::CHAPMAN () Mon Feb 24 1997 05:14

	The summary information an the end of the copy operation shows
	2 more blocks read from the old save set than written to the new
	one.

	The original save set is a reel-to-reel tape.  Are there extra blocks
	at the end of tape/start of tape in a multi-tape set. Or how do I
	explain the difference.

	This save set spans two reels of tape.

	Jim Chapman


	We really like the Save Set Manager.  We have 10 years of backups
	that need to be converted from reel-to-reel and TA90 and can not
	imagine doing this job without a product like this.  Well I can
	I just don't want to!

	Thanks
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68.1SSAG::SUSSWEINnever confuse having a career with having a lifeWed Feb 26 1997 14:3723
    Jim,
    
    There are a number of reasons that the number of blocks in an output
    saveset could be different from an input saveset:
    
    1) In the case of multi-volume savesets, each volume starts with a
    summary record, and ends with an XOR record (even for an incomplete XOR
    group).  When putting multiple input volumes onto fewer output volumes,
    it's normal for the output saveset to be 1-2 blocks/volume shorter. 
    Note that this applies to a normal copy, but not a copy/identical.
    
    2) The number of blocks will also change if you change the block size
    or group size.
    
    3) Often, especially on older media, there will be rewritten blocks in
    the saveset.  When the saveset was originally written, blocks might
    have returned a write error, and been rewritten by backup.  If these
    blocks were then found to be readable by SSM they would be ignored, but
    would still increment the "blocks read" count.  SSM generates an
    informational message when it encounters a rewritten block. 
    
    
    Steve