Are there any downsides to a restored image. Is it bit for bit perfect as seen by windows ?
For my own curiosity :) because I don't fully understand the finer details.
Hope the question makes sense. What I am getting at is to find out whether a restored image is in any way inferior to the original in terms of speed, and windows knowing where everything is, size of any "master file tables" identifying where everything is.
Bit of a deep question but it's something that I'd really like to know the answer too.
So if you take a disc image of the OS and then restore that image, and then repeat the process many times over, is your "final" restored image exactly the same as the first ?
I know when doing incremental backups that although the restored image of a backup tree "is the same" as the last incremental taken, it can't then be used to simply carry on taking images from in the same "tree" as the position of all the sectors ? (am I using the right word ?) has changed and so the next incremental would be huge.
Does that fact have any impact on the OS ?
Windows must know the location of all data/progs etc, so has that info changed ? if the restored image is all "moved up or down" a bit on the disk as it were.
Thanks for reading... hope someone has some insight into this.
I have found two errors in restored images on Windows Vista. They probably apply equally to Windows 7. I'm not completely sure if they apply if the image is restored to it's original disk, they certainly apply if you clone a disk by creating an image then restoring it to another hard drive. These errors are:
1) System Restore is turned off and so all restore points are lost. This happens because Windows sees the new root partition (C drive) as a new drive (with System Restore turned off by default) and the old C drive as "missing".
2) The BCD file used to boot Windows is altered. In particular, references to other partitions than the root drive may be lost. I have just had problems where the recoverysequence variable in the bootmgr section and the associated bootloader section which referenced the D drive were lost after cloning so the F8 option to Repair Your Computer gave an error message. I had to manually reconstruct the BCD file.
This pertains to True Image Home 2010 build 7,046 which (I think) is the current version.
Alan:
The root cause of the two issues that you found is the same. Windows references a partition by an identifier that consists of the disk ID and the starting sector of the partition. These references are pervasive in low-level Windows operations and are used by the System Restore mechanism and by the entries in the BCD that refer to partitions.
If you had originally created and formatted your partitions with the Vista (or Windows 7) installation disk (or DVD) then the first partition would have been created with the starting sector offset by 2048 sectors from the beginning of the disk. This offset is relatively new, having been introduced by Microsoft when Vista was released. TI, however, still uses the older standard where the first partition on the disk is offset 63 sectors from the start of the disk. So when you restore an image to a new disk, TI creates the partition table using the older offset rules. While these partitions will work properly, the low-level identifiers used by Windows will be incorrect. The result is just what you observed - all System Restore points will be lost and the setting will need to be changed to reference the new "C" drive. TI knows how to fix the BCD to refer to the new main Windows partition, but it doesn't know how to fix some of the other references to the F8 recovery boot mechanism or to other operating systems if you have a multiboot setup.
However, now that you've manually fixed things up you can create an image of the repaired system with 63-sector offset. This new image can be restored without issue since the offset will not change upon restoration.
This issue will be fixed if and when Acronis decides to code TI to handle 2048-sector offsets for Vista and Windows 7 partitions. They've recently done this with Disk Director 11, so there is hope...
As far as I know, restoring an Entire Disk Image along with the Disk Signature should preserve everything. Note that I've never tested this as I usually disable System Restore when I install Windows because it's failed every attempt I've tried using it to actually "fix" anything. Restoring an image is a much better solution, in my opinion.
TI 2010 should keep the offset in use on the original drive when restored to the original drive. Restoring to a different drive may change the offset. It depends on the partition configuration and restore options used.
Very interesting guys, thank you...
I'm using V.10 build 4942 with Vista and have to say it's been faultless.
Mudcrab,
I do restore back to the same partition... in fact I use TI to make running incrementals on the D partition of a laptop.
You have confirmed my suspicion that different sectors are used... it was whether that added in size to any file system causing "bloat" and slowdown that was my concern, or once the file system is updated is it as good as new ?
Alan,
System restore... I had noticed that system restore points were deleted, however for the last couple of years have had system restore turned off because like mudcrab I find it's neither one thing nor the other, and to me if there is a sudden problem then a quick image restore is best.
Mark,
Thanks for your explanation of the sector "offset"
If I understand correctly then once the first image and restore operation has been performed, and the offset altered, then any subsequent restores from future images are then put back in the same place (sectors) ?
Thanks again :)
Mark,
Thanks for your explanation of the sector "offset"
If I understand correctly then once the first image and restore operation has been performed, and the offset altered, then any subsequent restores from future images are then put back in the same place (sectors) ?Thanks again :)
The restored partition will start at the same starting sector upon future restores, so the issues with partition IDs becoming invalid will not recur.
However, sectors are not necessarily restored to their former locations. Usually the restored sectors are relocated to start at the beginning of the partition in sequence, much like a defragmenter will do when it reorders sectors. A restored partition is fairly well "defragmented", so to speak.
TI 2010 will keep the partition offset, if it can. It will also restore back to the same sectors, if possible. TI 10 can't do either of these with partition restores.
If you use TI 10 to create and restore Entire Disk Image backups, the offset and sectors should be preserved. However, this won't work when backing up and restoring to a partition on the source drive (a single drive in a laptop, for example).
The fact that different sectors are used does not increase the size of a Full image. It's still backing up the same data. If you need to "sort things out" again for performance reasons, just run a good defrag on the partition after the restore.
Thanks again MudCrab and Mark, for your clear explanations of what actually happens.
I've just run a full defrag using a command prompt to defrag all file sizes. (again like system restore, I have Vista's default defragger turned off).
Thanks Mark, that was a really useful response. When I was testing the Windows 7 Release Candidate I made the mistake of installing it on a partition I had created and formatted as NTFS with Disk Director (version 9, I think, not the current version). It all went badly wrong (incurable disk errors) and it all boiled down to the sector offset issue. So I'm not surprised there are implications for TI also.
The great thing about Windows System Restore is that you can revert your settings without having to worry about what documents you have added or changed since the Restore Point was made, as you would have to if restoring a True Image image. System Restore works very effectively and releiably unless you have security software that fights against it, like Norton or Kaspersky.
Alan:
You're welcome.
The problem with Disk Director 9 and 10 is an Acronis issue and is unrelated to the offset issue. Windows Vista and Windows 7 are both happy to have partitions with 63-sector offset (all of my disks are set up that way). The problem with corruption was due to the routines Acronis uses to format NTFS partitions. These routines worked okay with Windows XP but several observers have noted that they will result in eventual corruption with Windows 7. You can still create partitions with Disk Director 9 or 10, but you should not format them. Let the Windows installer do the formatting.
Mark:
Thanks for that further clarification. I had realised that it was at the (NTFS) formatting stage that things went wrong in Disk Director but when I last looked at the issue (over a year ago) it was the different sector offset that was being blamed. I only have a hazy understanding of such issues but the practical consequence rapidly became apparent.
Anyway, this is wandering off topic. I thought that Acronis might post a warning to check System Restore settings after restoring from an image but I could not find any mention of this problem. I have only just become aware of this issue myself. I often create a disk image as a fail-safe but it's not nearly so effective a fail safe if all the stored System Restore points are lost.
Alan... I've no problem with it going off topic... it's interesting. These are the issues and questions you never hear about and have to find out the hard way.