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Thread: HELP!!! i accidently formated my CF card

  1. #61
    Moderator Octarine's Avatar
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    Default Re: HELP!!! i accidently formated my CF card

    Quote Originally Posted by sabee View Post
    RAID is useless as a backup tool in most implementations. The whole point of RAID is to provide uninterrupted access to data in the case of a single drive failure. Having 2 or more drives hooked up to the same PSU and treating them as 'backup' is just asking for trouble.
    You are right, RAID is not a backup tool. But your backup device can use RAID technology in case of 'backup to disk'. Maybe it works better for some people here if we describe backup as 'offline copy'? Backup systems and the data stored thee are not in 'online access' mode. The question where the data are stored in is secondary. Backup on disk systems in industry practice especially when it comes to large amounts of data and short restore times (Virtual Tape Libraries, they work with RAID, too). Backup to tape is common practice for off-site storage (e.g. due to legal requirements).
    EOS

  2. #62
    Member Alan Chan's Avatar
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    Default Re: HELP!!! i accidently formated my CF card

    Quote Originally Posted by krazyman View Post
    You mind show me where you learnt this from?

    My stand is still that full format just does a additional scan to fix bad sectors compare to quick format, and you can read this Microsoft Support article Differences between a Quick format and a regular format.

    Here is another article on Difference between Full Format and Quick Format. And there are many more if you do a search.
    i've read articles of cases where some data can still be retrieved after formatting. i've also come across software that erase on byte level which is like 10x the time needed to format. so i think i agree with krazyman on this.
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  3. #63

    Default Re: HELP!!! i accidently formated my CF card

    Quote Originally Posted by krazyman View Post
    You mind show me where you learnt this from?

    My stand is still that full format just does a additional scan to fix bad sectors compare to quick format, and you can read this Microsoft Support article Differences between a Quick format and a regular format.

    Here is another article on Difference between Full Format and Quick Format. And there are many more if you do a search.
    The article you linked to refers to the difference between a regular format and a quick format during installation of Windows XP. Maybe there is no universally agreed definition of a full format, e.g. also on the Microsoft website (http://windows.microsoft.com/en-us/w...sks-and-drives - click on "What's a quick format?"), you can also find this:
    Quick format is a formatting option that creates a new file table on a hard disk but does not fully overwrite or erase the disk. A quick format is much faster than a normal format, which fully erases any existing data on the hard disk.

  4. #64
    Moderator daredevil123's Avatar
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    Default Re: HELP!!! i accidently formated my CF card

    Quote Originally Posted by tanpp View Post
    Although I don't have evidence to support this, I believe hard disk failure is correlated (how strongly, i don't know). So with regards to hard disk failure, and not human errors, controller card failure, power surge, and other factors etc, is it possible that doing backups have marginal advantages over a RAID1 since
    1. the hard disks are not being used the same amount of time,
    2. you could use different hard disks.
    Well, 2 is true for RAID too, but normally the same model of hard disks (and even the same batch) is used.
    Quote Originally Posted by Alan Chan View Post
    sorry bro if i misunderstand what you are trying to say, but if you backup a hdd you meant to use 2 hdd to save the same copy of 1 right? that means, your main hdd (in pc) and a external hdd to backup and both of them has the same photo right? isnt RAID 1 already using 2 hdd to store the same data? if you use another hdd to backup the data from the RAID 1, wont it be using 3 hdds instead?
    You see RAID 1 only protects against a single HDD failure (with the exception of RAID6). If you accidentally delete a file, the file will be gone in both drives in RAID 1. If a virus attack deletes everything in your system, the stuff will be gone from both your HDD in RAID 1. Because, even if you have 2 drives in RAID 1, the system only sees it as one logical drive.

    When you do a back up, you copy, then you remove the cable and store it somewhere else. It means it is more secure. If you make 2 copies in 2 separate HDD, it gets even more secure. If you take one of the backup drives and store it at your office, you are now super secure.

    Having RAID is just high availability (just to make sure system is still running when a HDD fails), it has nothing to do with any backup strategy.

    RAID is not data backup

    A RAID system used as a main drive is not a replacement for backing up data. Data may become damaged or destroyed without harm to the drive(s) on which they are stored. For example, some of the data may be overwritten by a system malfunction; a file may be damaged or deleted by user error or malice and not noticed for days or weeks. RAID can also be overwhelmed by catastrophic failure that exceeds its recovery capacity and, of course, the entire array is at risk of physical damage by fire, natural disaster, or human forces. RAID is also vulnerable to controller failure since it is not always possible to migrate a RAID to a new controller without data loss [9].
    RAID drives can make excellent backup drives, when employed as backup devices to main storage, and particularly when located offsite from the main systems. However, the use of RAID as the main storage solution cannot replace backups.

    From http://en.wikipedia.org/wiki/RAID#Ne...classification
    Last edited by daredevil123; 21st May 2010 at 05:55 PM.

  5. #65
    Moderator daredevil123's Avatar
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    Default Re: HELP!!! i accidently formated my CF card

    Quote Originally Posted by sabee View Post
    RAID is useless as a backup tool in most implementations. The whole point of RAID is to provide uninterrupted access to data in the case of a single drive failure. Having 2 or more drives hooked up to the same PSU and treating them as 'backup' is just asking for trouble.
    Yes, this is what I am trying to say thanks.

    One thing though, RAID 6 is able to withstand 2 drives going down at once. Problem is it needs at least 4 drives to implement.

  6. #66
    Moderator daredevil123's Avatar
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    Default Re: HELP!!! i accidently formated my CF card

    Anyway, I think all of us have gone OT enough. And I think TS has already solve his/her problem.

  7. #67

    Default Re: HELP!!! i accidently formated my CF card

    Quote Originally Posted by tanpp View Post
    The article you linked to refers to the difference between a regular format and a quick format during installation of Windows XP. Maybe there is no universally agreed definition of a full format, e.g. also on the Microsoft website (http://windows.microsoft.com/en-us/w...sks-and-drives - click on "What's a quick format?"), you can also find this:
    Thank for the link. Just realised that Microsoft had made changes to the Full Format for Windows 7. My fault that I didn't read till the end of the 2nd article that I've link which actually did mentioned about this difference in win7 full format.

  8. #68
    Member Zackt87's Avatar
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    Default Re: HELP!!! i accidently formated my CF card

    Quote Originally Posted by ManWearPants View Post

    Sandisk provide RescuePro
    http://www.lc-tech.com/rescuepro/
    i manage to retrieve back 1.8k of photos frm my SD with this program ... my harddisk is still nt working .. ... left last option which im nt confident in doing ... the freezer method ... anyone realli tried tt before??
    I'm just a photographer looking for my world~

  9. #69
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    Default Re: HELP!!! i accidently formated my CF card

    Quote Originally Posted by Zackt87 View Post
    i manage to retrieve back 1.8k of photos frm my SD with this program ... my harddisk is still nt working .. ... left last option which im nt confident in doing ... the freezer method ... anyone realli tried tt before??
    I would think you next option is to make a trip down to ADRC
    http://www.adrc.com.sg/index.html

  10. #70

    Default Re: HELP!!! i accidently formated my CF card

    Quote Originally Posted by daredevil123 View Post
    You see RAID 1 only protects against a single HDD failure (with the exception of RAID6). If you accidentally delete a file, the file will be gone in both drives in RAID 1. If a virus attack deletes everything in your system, the stuff will be gone from both your HDD in RAID 1. Because, even if you have 2 drives in RAID 1, the system only sees it as one logical drive.

    When you do a back up, you copy, then you remove the cable and store it somewhere else. It means it is more secure. If you make 2 copies in 2 separate HDD, it gets even more secure. If you take one of the backup drives and store it at your office, you are now super secure.

    Having RAID is just high availability (just to make sure system is still running when a HDD fails), it has nothing to do with any backup strategy.
    after the countless posts about raid 0,1,2,3,4,5,6 and back up hdd, this post probably explains best what raid 0,1,2,3,4,5,6 and back up hdd is.

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