Re: Imaging a "live" system

From: Craig Earnshaw (Craig.Earnshawat_private)
Date: Wed Jun 19 2002 - 08:32:58 PDT

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    Just a thought about imaging a "live" system:
    
    Take the following scenario - the system that you're talking about 
    imaging has a number of active users on it at any given time, those 
    users are reading from, and writing to, the drive in that machine, and 
    that the drive in the machine is anything over a couple of gig, lets say 
    5Gb.
    
    Even with really high data transfer rates it's going to take a good 20 
    mins to take the image of that system, in that time the active users on 
    the system will have written data to the drive, and the OS will also 
    have written data to the drive (logs etc).  The image of the system that 
    you end up with probably isn't going to be worth much as I would suspect 
    that large amounts of the data will be corrupt as, by the time that the 
    data in the last third of the drive is imaged its content, and layout, 
    will have changed to the point whereby it no longer matches up with its 
    layout when the image was started (ie at the start of the image process 
    a file resides in sectors 1, 23, 457, 1127, 28847, 28848, and 28856, by 
    the time that the image is completed the file may have changed and my 
    now reside in 2, 87, 332, 1127, 1128, 1129, and 1130 - no of your data 
    pointers would be pointing to the correct place for the OS to find any 
    part of the file).   Not quite sure if I'm explaining myself very well, 
    but I think it illustrates the concept.
    
    Any thoughts.....?
    
    Craig
    
    
    
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