Long verifies in Secure Zone

Discussion in 'Acronis True Image Product Line' started by HenryA, Oct 1, 2008.

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  1. HenryA

    HenryA Registered Member

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    I saww a mid-May, 2006, thread explaining long verify times in the Secure Zone because all backups there get verified, not just the one you recently added. The response was that a request would be sent to Development to provide a better solution. I'm hitting the same problem with True Image Home 11, so I guess it was never fixed. Is that the case? Wil True Image 2009 be any different?

    If I switch to using backup folders instead of the Secure Zone and limit the size of the folder so that I'm only keeping two or three full backups and their incrementals, will it just verify the current backup (and its incrementals)?

    Thanks,
    Henry
     
  2. Tabvla

    Tabvla Registered Member

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    Hi Henry

    Do you have a really good reason for using the ATI Secure Zone?

    If you do have a good reason can you explain why you have opted for the Secure Zone option rather than a backup on a separate disk.

    T.
     
  3. Xpilot

    Xpilot Registered Member

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    It is possible, indeed desirable, to run a secure zone on a seperate disk. I have been doing this for years with no problems at all.

    The original question was regarding length of verification times. These are an inbuilt,even architectural, faults of the secure zone and to an extent the special backup locations.
    In a secure zone when a verification is run the whole of the zone's contents is verified it is not possible just to verify the latest .tib.
    I believe the same applies to backup locations unless a single .tib is selected for individual verification manually. I cannot be sure of this as i do not use the "Locations" feature.
    Backing up to a disk,partition or folder without taking advantage of the secure zone or locations features enables .tibs to be verified individually.

    It is also possible to devise a backup strategy that does not involve the need to ever use backup verifications using the TI method.

    Xpilot
     
  4. HenryA

    HenryA Registered Member

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    The reason for using the Secure Zone on an external drive is partly historic; I don't think the backup folder option existed in earlier releases when we started using True Image. (At least I wasn't aware of it.) The reason for sticking with it in V11 was that is is more protected than a backup folder. But I'm not wedded to it, if folders work better.

    After posting my original mesage I did set up a backup folder, using a folder that already contained a couple of backup tib files. I ran a full backup with verification there. It seem that folders have the same problem that the Secure Zone does; all of the backups are analyzed, not just the one created in that task. I can't imagine why that should be the case.

    How?


    I know how to avoid verification, if I'm willing to give up that assurance, But is the reply saying there's a way to be sure without verification? How?

    Also, TI uses the terms "verification" and "validation", so I assume they mean different things. I interpret verification to be a direct comparison of the archive with the disk it is copied from, ensuring that every byte is correct, while validation simply checks that the structure of the archive is correct and usable, but doesn't look back at the original data. Is that interpretation correct? If so, I'm at a loss to see how old backups in a folder can be verified (rather than validated), since the original data are no longer available. So what is taking all that time?

    Henry
     
  5. Tabvla

    Tabvla Registered Member

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    Acronis are not known for semantic purity :) .... verification and validation mean the same thing.

    And these processes use a simple Hash Total for verification purposes. All this tells you is that the backup file is OK. What is does not tell you is whether the backup will restore. (Note : the explanation by Seekforever is much more elegant and accurate :)

    There is ONE and only ONE way to determine if a backup is good. And that is to restore it. If it is a System Restore then you need to test that the computer will boot from the restored disk/partition. If it is a Data Restore then you need to browse through a few files just to make sure that it looks OK.

    This is not something specific to ATI. It is in the nature of backups and this will apply to any backup software.

    The way to get around this is to use RAID 5 (or if you can afford it RAID 6) RAID 5 will tolerate the complete failure of 1 disk in the array. RAID 6 will tolerate the complete failure of 2 disks in the array. All RAID options impact in terms of both financial cost and use of system resources which can make a noticeable difference to system performance.

    T.
     
    Last edited: Oct 3, 2008
  6. seekforever

    seekforever Registered Member

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    I thought Backup Locations worked properly but if they don't you can just use a regular folder unless you want the quota etc features.

    Xpilot has drive caddies. After creating the image he easily switches the HD and does a restore of the just created image. This HD is now put into service. If for any reason it fails he still has the original source drive available off-line.

    Verification and Validation mean exactly the same thing to TI and I think Verification was used originally in the product. It does not do a byte by byte comparison of the original file. TI writes a checksum every 256K bytes (4000/GB) of data into the archive file. When you do a validate the archive is opened, read, and each of the checksums is recalculated based on the data read into RAM. If only 1 bit in 1 checksum is wrong the archive is declared corrupt. It is a pretty stringent read test. This is how it can be done without the unaltered, original source present. A byte comparison would never be possible with Windows live imaging because the source is always changing.
     
  7. Xpilot

    Xpilot Registered Member

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    TI only has one method of confirming the usability of backup images. In the good old days it was called verification. In more recent times it is called validation. Since you started by referring to verify that is the term I continued to use.

    A whole slew of check sums are recorded as an image is created. At any stage thereafter these sums can be rechecked, compared with the calculated sums and if all agrees the image is declared good.
    There is no comparison back with the original source data.

    The quaint rule of the secure zone is that all images are validated whenever a validation is run either at the time of creation or later. I don't believe this behaviour will ever be changed as it is deeply embeded in the program structure. I understand that the same applies when the special backup locations are used unless a validation is run as a seperate exercise, then an individual image may be selected.

    If backup images are kept in a normal file, folder or partition each can be verified on its own at the time of creation or later.

    Because of my desire to use the valuable and useful features of the secure zone and my dislike of multiple validations I chose to dispense with them entirely.

    I know beyond all reasonable doubt that my backup images are good because I use them to make frequent restores to a rotation of swappable hard drives. This gives actual proof that the images are good rather than an assurance that they are probably usable.

    Xpilot
     
  8. HenryA

    HenryA Registered Member

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    Thanks, all.

    Since validation = verification of checksums and not byte-by-byte comparison with the original, there's no need for it to be done in the same scheduled task that does the backup (which was the only place that used the word verification). I can schedule verification on a different night from the full backup.

    I'll test verification-only with one backup in a backup folder containing several backups to see if it does go through all of the other backups there as well. The reason for sticking with folders, as noted, is indeed that I want the automatic storage control. I'll post results here.

    RAID 5 ir 6 would be nice, if I could figure out how to stuff all those drives in a laptop. ;)

    We do occasionally test full restores on our desktop systems, but that only validates that particular backup and the practices we use, so it's not an assurance that we're always creating accurate backups. Still, I would imagine that errors are highly infrequent, and we keep several weeks of backups at any time. We only truly count on ATI to avoid the hassle of rebuiling everything after a hard drive failure. We have entirely separate procedures for backing up data and keeping a historical record archived off site. The ol' belts and suspenders approach.

    Henry
     
  9. HenryA

    HenryA Registered Member

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    I tested verification of a single archive in a backup folder with several archives. It seems to have just verified the one archive, so that's the solution I'll go with. Bye bye Secure Zone.

    Thanks for all the clarifications and suggestions.

    Henry
     
  10. oldaussiedog

    oldaussiedog Registered Member

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    This raises yet again the question of whether Acronis take any notice of what users participating in this forum are having problems with, or what they want from the product.
     
  11. Tabvla

    Tabvla Registered Member

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    Acronis Support does take notice of this Forum - Acronis Development does not.

    The primary reason for this is commercial. "Home" versions of many software products are used to introduce the customer to the product often with a view to extending that product from the Home to the customer's place of employment.

    Acronis commercial offerings sell for US$1000 per license!! You don't need a calculator to work out where Acronis Development spend most of their development budget ;)

    T.
     
  12. shieber

    shieber Registered Member

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    Since ATI works in background and the user might be using programs and Windows might be doing godknowswhat while the backup is being created, there's little point to doing a comparison of the backup to what's on the disk after the backup is completed. To deal with this situation Acronis chose to ember checksums in the backup so that it's integrity (actually its fidelity to how the file was originally written) can be checked after it is created. It's an ersatz way to test whether a backup got all the right stuff. The underlying assumpiton is that, if no errors popped up during the backup, then the backup is faithful and subsequent corruption of the backup is the only thing of interest.

    The better way to test a backup is to do a test restore ocassionally to ensure that everything works as desired -- after all, it's at the restore stage that real disappointments count the most.

    sh

     
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