Tech PC Talk Backups

This topic contains 13 replies, has 6 voices, and was last updated by Bob Williams 4 months, 3 weeks ago. This post has been viewed 375 times

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  • #12105

    dwynnehugh
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    • @dwynnehugh
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    A friend of mine has just asked for an external HDD to backup his collection of photos – his ‘C’ drive is 1TB – do I get him a 1 or a 2TB ext HDD – there will come a time when his ‘C’ drive will be close to capacity and still 50% of his ext HDD available – give or take.

    I believed that a backup HDD was to ensure that you had a full copy of data etc on both int and ext HDDs?

    Your views please.

    To err is human, but forgiveness is not Tory policy!

    #12106

    Dave Rice
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    • @ricedg
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    If it’s raw files they will compress, if it’s jpegs they are already compressed. In any event I would go for at least 2TB to allow for multiple backups.

    Maxtor portable 1TB £47

    Toshiba Canvio portable  2TB £66

    Toshiba Canvio Desktop 3TB £77 (portable £90)

    Desktop or mobile 4TB £100

    Personally I would go for the desktop 3TB.

    #12107

    Ed P
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    • @edps
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    Just a tip to pass on to your friend, it is better not to try to compress photo files for two reasons:

    a) As Dave points out they are already in a compressed format.

    b) Where possible (and time permits)  any photo backup should be checked for corruption caused by the copying process.

    I do not have independent stats on file corruption but corrupt headers are fairly common. I’d guess that it could be at least 1:1000 that are corrupt in some way. From bitter experience, that number sky-rockets if you compress the jpg.

     

    JPG Checker is a checker for Windows. (not now free). I have used it in the past when it was free and it was fast and accurate.

    If he knows how to use Python then PIL is a good method as it actually loads and tests each image and prints out an exception for those that fail. Unfortunately this really only detects corrupt headers, not image glitches.

    Python code, (needs to be put in an appropriate loop):

    from PIL import Image

    v_image = Image.open(file)
    v_image.verify()

    If he knows Linux then jpginfo is a free way method.

    This is not an exhaustive list of methods, but rather to encourage your friend to do it if the photos are at all valuable. He can find more by searching on-line for  “check jpg files for corruption”

     

     

    #12108

    Dave Rice
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    • @ricedg
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    Aimed at serious photographers only, Synology are touting their NAS with the BTRFS (Better File System) as it’s self healing.

    It’s only available on the high end chassis i.e. a 2 bay is nearly £400 without disks. But for a professional it’s money well spent.

    #12111

    dwynnehugh
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    • @dwynnehugh
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    Thanks one and all, I think without checking he’s a ‘happy snapper’ – holidays and suchlike, don’t think he’s into it in any professional way.

    He’s more into having a 2nd copy of his images which is why I asked the initial question – xTBs?  Obviously if he has a copy on his ‘C’ drive which is 1TB and gets a 2TB ext HDD there will come a time when his ‘C’ drive will not have the capacity to keep the same number of images as his external one.

    To err is human, but forgiveness is not Tory policy!

    #12113

    Ed P
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    • @edps
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    A second copy of family stuff is always nice to have, but useless if it is corrupt. I’m not a pro but I was gutted to lose some photos I took in Bhutan. (a rare place at a rare time – a couple of years before they got TV).

    #12120

    Dave Rice
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    • @ricedg
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    This chart is from a Synology course I went on. It’s based on years of looking at NAS drives.

    #12128

    Bob Williams
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    • @bullstuff2
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    That is scary Dave.

    “If you think this Universe is bad, you should see some of the others.”
    ― Philip K. Dick, legendary SF writer.

    #12137

    Ed P
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    • @edps
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    Do I read that correctly – One 1TB drive (full I guess) has a probability of ~10% that at least one byte on the drive will be totally corrupt? That actually sounds quite low so I’m probably misreading it .

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