Is all compression the same?

Discussion in 'backup, imaging & disk mgmt' started by acr1965, Dec 30, 2012.

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  1. acr1965

    acr1965 Registered Member

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    I see that with many backups and images the ability to compress, encrypt & password protect. Is compression ability pretty standard across the industry? I'm looking for a solution that will compress the "best" whatever that is...I guess make the smallest sized backup. With a 250 GB drive that is about 200 GB full (mostly songs, video and some software programs) what size should I end up with if an image is made/ compressed / encrypted ?

    Also, is it safe to save an image to a portable hard drive (I hear some fail after a while) ? Or is there a cd or dvd an image can be saved to that has enough space for an image to be saved to? If so, is there any particular brand that works best or brand to avoid?
     
  2. TheRollbackFrog

    TheRollbackFrog Registered Member

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    If an image contains mostly anything other than MUSIC and MOVIES/VIDEOS, a decent LOSSLESS compression will come in at 50-60%. Music and movies/videos are already fairly well compressed by CODEC design and as a result will not compress much further.

    A PORTABLE hard drive is usually nothing more than a regular desktop/laptop drive enclosed in a case with some hardware that does a data stream conversion from USB to the hard drive's interface (SATA or IDE)... it's as good as the hard drive itself. If the data stream logic fails, the drive is still good... it just needs to be re-atached with a new case to be functional... "in most cases."

    BluRay writable discs would be the only thing close enough and for a compressed 200gB storage element (100gB best compression), you'd still need multiple discs to save an image.
     
  3. andylau

    andylau Registered Member

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    250GB just has one partition only?
    Has it installed OS?
     
  4. acr1965

    acr1965 Registered Member

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    good info, thanks
     
  5. acr1965

    acr1965 Registered Member

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    well it's supposed to be a 250 GB hard drive..c partition shows 222 GB and d partition shows 10.
     
  6. Keatah

    Keatah Registered Member

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    In thinking of NTFS whole-disk compression:

    200GB of "uncompressed" media files like mpg jpg mp3 and so on might compress down to 193-199 GB. And much of that space savings is going to come from different & more efficient usage of slack space on the disk.

    IMHO not worth the trouble or overhead & wear and tear of multiple reads and writes necessary to just read the stuff back. Not to mention much more fragmentation on a mechanical disk.
     
  7. Keatah

    Keatah Registered Member

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    I ran a quick test with Acronis 2011. I did a backup run of an 11GB folder full of MP3 files. I used the Maximum compression setting.

    Uncompressed = 11,830,562,394 bytes
    Compressed = 11,558,023,680 bytes

    This translates into roughly 4GB savings per 100GB.

    Understand that any backup medium can fail. To be safe you need to play a game of statistics. If anything is really important, keep 2 copies on 2 separate mediums, aside from the working copy you use daily. If you plan on backing up 200GB of media files I'd still recommend purchasing 2 separate hard disks, they're dirt cheap anyways. Otherwise your next viable option would be BD. And you'll need a pack of 20 to cover the job. Assuming one or two coasters and assuming you're making 2 copies.

    The advantage goes to the HDD for many reasons, it can easily be updated. And in the case of media files, like pictures, movies, and music, you just drag-n-drop the files over initially. You then use a sync program such as FreeFileSync to update the backup against your working copy. One among many choices. It's works well for me since I can review the changes prior to it doing anything.

    Don't bother with any kind of imaging tools or compression. It's just another layer in the system to go bad. And as I have demonstrated, the space savings is minimal.

    Encryption you ask? An encrypted dataset might take a tiny microscopic bit more space compared to a non-encrypted backup, but certainly nothing to warrant considering different methods & mediums in this case. Here you either check the encryption box or you don't.

    If you purchase 2 different disks from 2 different mfgs you've dropped the possibility of loss to almost nothing. Infinitesimal. Really. And 2 copies really goes a long way to protecting against user idiocy. There have been times when I messed up a backup (or had my backup FAIL). But aside from having to do a drive across town I was not inconvenienced in the slightest. A lifesaver to have had another tertiary copy elsewhere.
     
    Last edited: Jan 3, 2013
  8. acr1965

    acr1965 Registered Member

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    that's a lot of real good info, thanks for the time writing it out...I'll plan to do as you suggest and for some of the extra important files i'll try to send a 3rd copy to skydrive or gdrive...something like that, besides also saving to disk. thanks again.
     
  9. Krysis

    Krysis Registered Member

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    Excellent advice!! :thumb:

    Interesting stats on compression values! - I've never bothered to check compression values before as I have 3 external HDDS - something to keep in mind in future. :)
     
  10. Keatah

    Keatah Registered Member

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    Yep. It is good advice, something that has served me and many colleagues' and family members extremely well since the dawning days of the 3.5 formfactor HDD (and Apple II & pre-Pentium days).

    The concept was the same back then, except we would dangle the disk outside the case when doing copy operations. I'd have an IDE cable and power connector running out the back of the computer. And we'd plug in a bare disk. As long as you treated the cable connectors with respect it worked really well.

    Then came along ZipDrives and JazzDrives. And we used those. Then 1394 FireWire and USB disks blew into town. And here we are!
     
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