Space required on the partition to "receive" a disk image backup?

Discussion in 'Acronis Disk Director Suite' started by TKHgva, Mar 21, 2009.

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  1. TKHgva

    TKHgva Registered Member

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    Hello,

    I am a soon to be Acronis Disk Director Suite user (I'm waiting for the software to arrive by mail any day now). Same for True Image.

    I was just trying to get myself prepared as to partitionning and backing up, but I couldn't find a specific answer to my questions/doubts by searching the net with key words. I hope someone can be kind enough to help me out here.

    Disclaimer: I am a beginner with backup and disk management (partitionning). Patience please!

    Question:

    My system is Vista Home Premium Sp1, 32b. I have a Sony Vaio laptop with 140GB on the internal HD. I have in addition a portable Western Digital external HD with 500GB free space (using USB 2.0 for transfer).

    I wish to use True Image to make a backup of the internal HD, rather the OS, onto the external HD. Therefore I wish to create a partition on the external HD to "receive" the disk image.

    How large should the partition be on the external HD to receive a disc image from the internal HD?
    What I mean is I wish to backup my OS (Windows Vista) & Programs using a disk image and store those backups (images) on the external HD which is 500GB, so how large should I configure the partition on the external HD for this backup image to be stored in it? (I'm not even exactly sure what I must backup from the internal HD, but I'll ask in the appropriate forum for True Image).

    Thanks a lot for any of your time.
     
    Last edited: Mar 21, 2009
  2. K0LO

    K0LO Registered Member

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    TKHgva:

    When you back up a partition with True Image (TI), the result is a file, albeit a pretty large one. This file can be copied, pasted, and manipulated just like any other Windows file. So to answer your question about the external drive, partitioning is not required. You can simply use the Windows folder/file scheme to keep your backups organized.

    To estimate the space required for a backup, do the following. Determine the used space on the drive from Windows Explorer by right-clicking on a drive and choosing "Properties". Subtract the sizes of the hibernation file (if any) and the paging file (C:\hiberfil.sys and C:\pagefile.sys). TI includes only placeholders for these files because Windows re-creates them when booting. By excluding them, TI makes the resultant backup image file smaller.

    After determining the used space minus hiberfil.sys minus pagefile.sys, multiply the result by 0.7 to account for compression. The answer is an estimate of the size of the backup (image) file. The factor of 0.7 is for normal files. Music, photos, and movie files are already compressed and will not compress much more, so you may need to adjust your estimate upwards if you have a lot of these.

    As an example, assume that the used space on your C: drive is 140 GB, the machine has 2 GB of RAM so that hiberfil.sys is 2 GB and pagefile.sys is 3 GB. The resultant image file will be about [(140 -2 -3)*0.7] = 95 GB. Your 500 GB drive then could hold about five of these image files.

    I'm guessing that you probably have most of the 140 GB in user files (music, photos, videos, etc). If so there is a smarter way to back up. Many on the TI forum will recommend that you partition your laptop's drive into an OS partition and a user data partition. Store all of your user files on the data partition. In this way the OS partition will be smaller and easier to back up. For example, if you do this and end up with 20 GB of used space on the Vista partition then its backup file will be about [20 -2 -3]*0.7 = 10 GB. TI can usually back up at a rate of 1 GB/min, so backing up your Vista partition may only take 10 minutes and you will be able to store many more OS images on your 500 GB external disk. And, if the OS ever gets corrupted you can restore it from a backup without affecting any of your user files.

    For backing up your personal data files, TI is not the best method in the opinion of many TI users. Instead they recommend using Windows Explorer to copy/paste them to the external drive, or automating the process with sync software like Karen's replicator or Microsoft SyncToy. In this way your valuable data files are stored in their native format instead of being stuffed into one large proprietary-format file.

    I'm sure if you posted a question about backup strategy on the TI forum that you'd get a variety of opinions to help you decide. Several of us here will be glad to help you partition either your laptop's drive or your external, so post back when you get to that point.
     
  3. TKHgva

    TKHgva Registered Member

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    K0lo,

    Thank you indeed for your very clear explanations and step-by-step presentation. It's all much clearer now. Good thing novices like me can find advice practically instantly thanks to this forum.

    I see. A good thing you explained the end result of a partition when using TI (=normal windows file); it's not evident at first.

    1) But to link with your reply to my other thread where you explain partition management (defragging), wouldn't it still be beneficial to use partitions on an external drive, to separate between the different types of files stored there and to group together same type files? For example all media in one partition, disk image backup in another, all Word/pdf in another etc.

    I'm learning a lot here! I just had to go over to Wiki to check the definitions of the two above-mentionned files. Is my understanding correct:

    2)
    Hibernation file=data transfered from RAM to the hard drive before hibernation/sleep on the laptop, then restored to the RAM so we can continue from where we left the desktop at hibernation/sleep?

    Paging file=auxiliary storage room on the hard drive used when RAM memory is full?

    So > Both the hibernation and paging files are located on the hard drive (physically), and therefore "taken into account" when proceeding to create a disk image with TI (>will appear in the "result" file of TI), but both files will actually "disapear" or "empty" upon system shutdown, therefore only "existing" during a session. Correct?

    3) So "placeholders" in TI sort of proposes a solution for handling these files? Can you kindly explain what is meant by "placeholders"?

    Good to know. Thank you once again >we learn a lot here.

    Not only does one find help for using the software, but also good advice on our system management.:thumb:

    4) Why would one need to have more than one OS image backed up?

    5) The WD Passport Essential ext drive that's linked to the laptop says it uses "sync". But this feature on the WD drive is not for backing up, it's so that when I alter an open document/file (located on the ext drive) on the desktop >it is automatically and instantly modified on the ext drive as well. Is that the function of Western Digital's "sync"?

    6) You mean that if OS and data files are kept on the same partition, and therefore backed up together as "one" single disk image, it makes it more complicated to go fetch those files after a system corruption/failure >or rather it makes it difficult to seperate what is to be restored or not in the case of having to restore a disk/partition back again?

    Well that's very generous on the forum's behalf! I appreciate very much the help on this forum and Wilders in general. Maybe after seeing all these questions I come up with, it will make you change your mind on the above offer...:)

    Your explanations were more than clear and boosted my understanding of these "unexplored" areas of my computer system. If I hang around this forum enough, maybe one day I'll even dare to explore into THE Registry.:)
     
  4. K0LO

    K0LO Registered Member

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    That is possible, but you can also do this by making separate folders for each type of file. I suppose that you can make an argument that if certain type of file system or disk corruption occur, you will be better off with separate partitions because the corruption may affect only one of the partitions; not all of your files. That's a personal choice you will need to make.

    The hibernation file is only used when the PC is hibernating. When sleeping, the data is just held in RAM and power to RAM is maintained. By doing this the PC can "wake up" almost instantly, but if power fails then the data is lost and Windows has to start over with a reboot. Windows Vista has a "Hybrid Sleep" mode where it does both -- keeps RAM alive and also writes a hibernation file. When a PC is in sleep mode you will lose data if the power fails. With hybrid sleep if power fails the PC just comes out of hibernation when you power it back on without data loss and just picks up where you left off.

    The paging file is part of Windows memory management. Data blocks are swapped out of RAM and into the paging file whenever the memory manager needs more RAM. If you have a lot of RAM then very little use is made of the paging file unless you have a real RAM-intensive program running.

    When Windows boots up the contents of the paging file are discarded and the system starts fresh. After resuming from hibernation the hibernation file is also discarded. Therefore, all TI needs to know is the size of the two files. It does not need to back up their contents. So instead, TI stores a "placeholder" for each file, which is simply a small file that is empty but contains the desired size for the file. When TI restores an image it re-creates the two files at their desired sizes but empty of data. By doing this it saves space in the image file by not wasting space backing up data that will be discarded later. I didn't mention this earlier, but in addition, TI only backs up hard disk sectors that are in use; it does not bother backing up unused sectors.

    It is helpful to have several backups available as insurance. You never know when a) you will accidentally delete a very important file, b) one of your backups may be corrupted, or c) you would like the ability to restore the PC to an earlier state. As an example, I am currently installing Windows to a new laptop. So after doing a clean install of the OS I save an image. Then I start downloading Windows updates and drivers. After getting everything working I save another image. Finally I install application software. When everything is working I save another image.

    If something goes wrong with a faulty software installation I can simply go back a step instead of starting over completely from scratch.

    I am unfamiliar with the WD app, but it sounds like that is what it is doing.

    No, if you dump everything together in one partition then the size of your backup image is much larger and it takes longer to back up. The longer it takes, the less likely you are to do it. If you keep your OS partition fairly small the it will back up quicker and you will be more likely to develop good backup habits. Also, if the OS crashes and you need to restore a backup, then you can do this any time you want without changing your data files if you keep your user data on a separate partition.

    This forum, and the TI forum are good reading -- you will learn a lot about the Acronis programs and about Windows by reading some of the postings. Good luck!
     
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