Constantly Backing Up

Discussion in 'Windows 7 Hardware' started by Heaven or Hell, Oct 2, 2011.

  1. Heaven or Hell

    Heaven or Hell New Member

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    I know of the option to back up your data on an external hard drive, at
    intervals, but in the past few years I've heard of "constantly backing up" which
    is basically that whenever something is downloaded on your computer, an exact
    copy is made on the external drive. All downloaded programs/applications on the
    computer are also reflected on the external drive, so I guess this is what
    imaging is all about.

    I understand this is so that if you're computer gets into an unrecoverable
    state, the backup drive would be there to the rescue. Now my question is, if
    your computer screws up through an update, virus, or the like...wouldn't the
    external drive get affected in the same way? It's constantly connected to your
    computer and reflecting everything from it onto itself, so wouldn't any
    malfunction or malware creep into it and screw it up as well?
     
  2. patcooke

    patcooke Microsoft MVP
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    Depends on the cause of the problem - infection, soft error (bad file contents), hard error (physical damage to the drive) etc. An infection may or may not infect more than one drive, a file which has suffered data corruption will obviously be copied with the corruption. Hard disk errors will be limited to the drive on which they have occurred and should be looked after by the op sys as long as they are not catastrophic.

    There are two basically different ways of making backups. The first is to just save a second (or third) copy of data files on another drive (usually external). This method is most usually used for data files. The second is to make an "image" of the drive or partition which can be restored in its entirety. This is usually applied to a system drive and creates a single file which is an image of the thousands of individual files (operating system, installed applications, drivers, registry etc) which make up the system drive. It is usual to maintain the most recent three images. Because the image can be quite big it is good practice to keep the system drive to the smallest possible size by ensuring that all user data is stored on a separate drive leaving the system drive for just software and associated files. The are quite a few imaging systems on the market, some free, some needing to be paid for - I personally like Acronis True Image.

    Whatever methods you adopt, data file backup and system imaging are essential if you are to maintain your data safely and avoid spending a very large part of of your time reinstalling systems and apps.
     
  3. Digerati

    Digerati Fantastic Member
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    Nope. Bad guess. An "image" backup is just that, a mirror "image" of your hard drive (not files) is saved as a backup file. Image backups could care less about the files or folders on your drive. It just takes a picture, if you will, of each and every byte and sector on the drive (full of data or empty), then restores the entire drive upon restoral.

    To answer your question, you are correct that "real-time" backups, as you indicate, can indeed contain malware or a corrupted file. This is why it is necessary, as patcooke suggests, to keep multiple backups to maintain a history of changes, and not just the most recent. So you can, if necessary go back in time until you reach a clean backup.

    An image backup is generally used in the case of a catastrophic failure, such as a drive failure. It would not normally be used to recover files that were accidentally deleted, for example.
     
  4. patcooke

    patcooke Microsoft MVP
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    Basically true - data file backup is best achieved by copying to external drives whereas imaging is primarily to give you the facility to restore a complete partition or drive - but the better imaging systems will also have a facility to "mount" the image as a virtual drive and extract selected files and folders giving you the best of both worlds.
     
  5. Digerati

    Digerati Fantastic Member
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    Of course the most issue is to have a backup plan, and then use it. Sadly, most users don't and that is bad logic because it is inevitable that EVERY hard drive WILL fail, soon or later.
     
  6. Saltgrass

    Saltgrass Excellent Member
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    If I remember correctly, Acronis will add updates or changes to an image. I do not believe Windows Backup will do that, but I have been wrong before. What Patcooke refers to about mounting an image seems familiar, but not sure you can do that with Windows Backup since I have nothing to mount it with.

    You can set the Windows File Updates to back up just the changed files, but that is not an image.

    Currently, I keep a second hard drive in my system and backup an image to it about once a week. But I don't really have any time sensitive data. It would be up to you to determine how often a backup is made.

    I do have an external drive I can backup to an about once a month I will do that. You can backup on a network, but I have not tried that.
     
  7. Digerati

    Digerati Fantastic Member
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    Then it is not a real "image". Updates and changes typically result in file fragments getting moved about and that requires the disk's allocation tables be updated too. That is not how "image" back ups work. Image backup software does NOT update changes to the MFT or FAT in the image file. That's "file", as in 1 file.

    Now a backup program may make an image, then the program may keep track of updates and changes in separate backup files. Then AFTER the image is restored, the updates and changes are applied to bring the system current. But an image is a "snapshot" of a point in time and image software cannot go back in time and change history.

    Remember, most image backups are burned to optical disks, many, if not most of which are WORM disks (write once, read many).

    See Disk image - Wikipedia, the free encyclopedia
     

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