differential vs incremental

Discussion in 'Acronis True Image Product Line' started by chris andrews, Feb 2, 2006.

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  1. chris andrews

    chris andrews Registered Member

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    Can anyone point me a good resourse where I can find out more about differential backups? I went w/ incrementals, and the number and total size of my images has gotten out of control, and impossible to archive off to dvd, without screwing up the schedule and turning my job into full time DVD burner. Does Acronis have any good documentation on this subject? Cant find in usermanual.pdf
    thanks much
    OutofSpace :p
     
  2. Mem

    Mem Registered Member

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    1.4 What is full, incremental or differential backup?
    Acronis True Image can create full, incremental and differential backups.
    A full backup contains all data at the moment of backup creation. It forms a base for further incremental or differential backup or is used as a standalone archive. A full backup has the shortest restore time as compared to incremental or differential ones.
    An incremental backup file only contains data changed since the last full or incremental backup creation. Therefore, it is smaller and takes less time to create. But as it doesn’t contain all data, all the previous incremental backups and the initial full backup are required for restoration.
    Unlike incremental backup, when every backup procedure creates the next file in a “chain,” a differential backup creates an independent file, containing all changes against the initial full archive. Generally, a differential backup will be restored faster than an incremental one, as it does not have to process through a long chain of previous backups.
    A standalone full backup may be an optimal solution if you often roll back the system to the initial state (like in a gaming club or Internet café, to undo changes, made by the guests). In this case, you need not to re-create the initial full image, so the backup time is not crucial, and the restore time will be minimal.
    Alternatively, if you are interested in saving only the last data state to be able to restore it in case of system failure, consider the differential backup. It is particularly effective if your data changes tend to be little as compared to the full data volume.
    The same is true for incremental backup. In addition, it is most useful when you need frequent backups and many restore points. Having created a full backup once, if you then create an incremental backup each day of a month, you will get the same result as if you created full backups every day. However, the cost in time and disk space (or removable media usage) will be as little as one tenth as much....

    ...An incremental or differential backup created after a disk is defragmented might be considerably larger than usual. This is because the defragmentation program changes file locations on disk and the backups reflect these changes.Therefore, it is recommended that you re-create a full backup after disk defragmentation.
     
  3. Acronis Support

    Acronis Support Acronis Support Staff

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  4. chris andrews

    chris andrews Registered Member

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    I have been repetedly been pointed to the PDF users guide. I would ask that next time an Acronis rep refers a client to "RTFM", they better be sure that what they are talking about is actually in there. Go ahead - dl the user PDF for TI 8 for Win Svrs. Do a search on the word "differential". Not mentioned once. Masters and incrementals... that is all. I get two choices for a new task (schedule task) Master Image and Incremental image. NO DIFFERENTIAL CHOICE ANYWHERE. If it is in ANY manual or users guide, then please. tell me where... what page, or section. I am out of space and I need a solution. Scared to call TS, for fear I get told to RTFM once again. Perhaps Differential and Master are the same thing? Could someone actually tell me how to create differential images with the new task wizard in ATIFWS8? That would help. Thanks
     
  5. TheWeaz

    TheWeaz Registered Member

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    First, you make no mention of what version of the TI application you are running.
    Then you are directed to the “Acronis True Image 9.0 User's Guide”.
    And then, you gripe about not finding what you want in the “user PDF for TI 8 for Win Svrs”
     
  6. noonie

    noonie Registered Member

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    Search thru the forums and you will find that many Ti users find that their incremental and differential backups are "out of control" as you put it.

    The resources that you will read about elsewhere concerning this subject can be misleading because "Data Backup Programs" do inc. & diff. backups very well because they use the "archive bit" of files. Therefore the inc. & diff. are much, much smaller.
    Ti does not use the archive bit, because it is an "imaging program" and very simply images anything that has changed, including the os that inherently changes enough, just in normal use, therefore the huge images. For example, make an image of your data, then defrag, then reboot, then make a new image. You will have another huge image. Backup programs that use the archive bit won't do this. It is just a marketing ploy, since most other backup progs can do inc & diff, Ti has to advertize this too, since most people want a simple "do all" solution.

    Ti does what it is intended for very well, and that is, ti images or clones a partition or drive, primarily so you don't have weeks of reinstalling to bring an os back to square 1. Luckily, all the data Can come with it, and that Can be a plus, but I certainly wouldn't solely count on it.

    The most foolproof way of using Ti is to have a C drive for the os and temp data files, partition a D drive for data and aim all your progs to automatically save to that partition. Then daily, or whenever, you can drop and drag to a burner or external drive, or network or wherever for additional data backup. You can use a simple utility like robocopy (in windows) or it's pal xxcopy or any file based data backup prog to automate this.

    In short rely on Ti for the os. Use Ti when you install new progs or alter the os and clone or image the complete drive.
    Rely on your own method for your data, as much as daily.

    Scan this forum for lost data files horror stories. I'm sure you don't want that. I have had customers there and have had 100% results since they impliment a method like the one I described.
     
  7. Acronis Support

    Acronis Support Acronis Support Staff

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    Hello Сhris,

    The point is that you did not mention what Acronis True Image version you use and so I thought it was Acronis True Image 9.0, especially since only Acronis True Image 9.0 has a capability of creating differential images.

    As I have already pointed above, you can find more information about differential images in Acronis True Image 9.0 User's Guide.

    Please also note that the ability to create differential images will certainly be implemented in the future versions of Acronis True Image Server for Windows and Acronis True Image Enterprise Server for Windows which are planned to be released in the nearest future.

    If you have any further questions concerning Acronis software, please feel free to submit a request for technical support or post any of them on this forum. We will certainly try to help you in resolving any issues.

    Thank you.
    --
    Alexey Popov
     
  8. wysocki

    wysocki Registered Member

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    I did a backup of "entire disk contents" (C: and D: partitions) to E:\MyBackup and selected Full Backup. In 20 minutes it created a 31.3gb file from the 47.2gb of data on those partitions. I edited two .txt files and then immediately ran the same script except I selected "Incremental Backup". The resultant file took 25 minutes and was 31.2gb. Why does TI even suggest it can do an incremental when it doesn't use the archive bit and obviously doesn't have a good alternative to it. Why would I ever bother to do an incremental disk backup like this?
     
  9. TheWeaz

    TheWeaz Registered Member

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    What version/build are you using? I believe there was a problem with an older build where the first Inc was, indeed, about the same size as a Full.
    FYI - I had an AV app once that used the archive bit and rendered my backup program useless. The archive bit is not the supreme answer to backup solutiuons. :D
     
  10. wysocki

    wysocki Registered Member

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    Version 9 build 2337 trial. I ordered it from Tigerdirect (before I found out about the trial) but it hasn't come in yet (I hope I wasn't stupid). Outside of the archive bit, the only way to do an incremental is to keep track of the size/date of every file yourself and compare as you go. Since it took so long this is what I assumed was happening. I think I found my mistake though...

    Initially, I sent my Full Backup to a file named E:\Full Backup.tib, then when I did the incremental, I thought it should be in a different file so I set up the job to write to E:\Incr Backup.tib and this ran as long as the Full Backup. I just started another, second incremental and left the filename as E:\Incr Backup.tib for output, thinking that maybe it nested incrementals inside the given filename. But it created E:\Incr Backup2.tib and, although it ran another 15 minutes, the file size of that on is only 506mb! So it would APPEAR that it IS an incremental. I wonder what makes up that 506mb though since I only edited one txt file (I really wish it did SOME estimate of output size for me).

    So I guess if I'm not using the Secure Zone, My Full / Incremental filename should always be the same in the scheduler (YES/NO)?
     
  11. TheWeaz

    TheWeaz Registered Member

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    If you schedule an INC backup and no FULL exists with the same name, has you've discovered, TI will create a FULL. The next time it runs, it will be an INC.
    Between System Restore Points, Application Prefetch Optimizer, yada yada yada, 500MB of changes you, yourself, did not create, isn't too farfetched. Plus, a file does not have to change, only move.
     
  12. herojig

    herojig Registered Member

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    Well, here is my 2 cents after using ATI for a year or so. Since I defrag the drives everyday using Diskeeper, I had to change my workflow for backups as the sizes of collecting incrementals is just too much for a daily/weekely backup routine, so I just schedule one job once a week (full) under one file name, and another daily (also full) under another file name. That way I have one previous week and daily backups as well, all without an increase in file sizes. The jobs are overwritten, and not added too.
    jigs
     
  13. noonie

    noonie Registered Member

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    Hopefully you alternate backup hardisks also to prevent pnysical failure of the backup disk too.
     
  14. herojig

    herojig Registered Member

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    well, i had not thought of that but that seems like a good idea, i backup to a trusty and newer external drive. I wish ATI had better compression, I have a 250 gig dedicated just to back up a 1 desktop and 1 laptop's essential programs and data. I now have 3 more computers on our home/office lan, and i am not sure what to do..buy more hard drives I guess. I used to put the backups on DVDRW everyonce in a while, but that's just too much work at 4gig a disk. I used to think incrementals were cool until Diskeeper upgrade, which increased the sizes of the backups x 3 or 4. arg. I guess it's just a headache. But ATI beats anything else I've tried. Thanks!
    jigs
     
  15. Xpilot

    Xpilot Registered Member

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    Defragging every day? That sort of housekeeping is totally out of my range of experience. Does it really make much difference to the whole computing experience? I would have thought that the extra processing time in producing backups and running Diskeeper daily would more than offset any savings.

    But each to his own:))

    Xpilot
     
  16. herojig

    herojig Registered Member

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    Absolutly Xpilot! We are a media studio and have noticed performance improvements on our media drives when they are defragged. Diskeeper is set to run when ever the machines are idle (screensaver) and according to the graphs and charts in Diskeeper, we are so so cool. Seriously, we can't afford any glitch in a sound or movie file, so we are hoping this helps...
    jigs
     
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