How ATI makes incremental backup?
Hi! How Acronis True Image makes incremental and differential backups? Does ATI scan every time full backup copy to find changed files or changed blocks in files? If contents of file was changed, but file creation/modification date and it size was not changed does ATI will backup this file?
I searched this info in howto, documentation and forum and find nothing :(
Thank you for response!
Will be ATI to calculate MD5 (or other hash sum) for every file on online disks and compare this hashes with hashes of files in full backup? It very expensive and long operation! Who and when do this work?
Oracle Database (for example) doesn't change modification dates of it datafiles, becouse: 1) this files change continuously and this operation will consume some i/o resources to change file attributes; 2) Oracle works with datafiles via direct access (without OS cache). If size of this files will be the same does acronis fell that files was changed?
I want understand algorithm that ATI use to find changed files and find changes blocks if files.
Unfortunately, I I have no idea and that would probably be something that the support engineers would need to answer for you. I can say that it is using Microsoft VSS for volume snapshots while Windows actively running and VSS is supposed to handle open Oracle and/or SQL datbases as of the point in time that a backup is initiated. I am just not sure what triggers the database change either. Some products, for instance MS Office products like word, excel and Access are first applied in memory and not on the hard disk so if the user has not saved the file or does not have autosave enabled, then those changes will not be backed up since they are in RAM and not on the disk. I don't believe this is the case with Oracle though, but something you may want to research on the Oracle side more to be sure.
As a secondary precaution, I would also be using Windows Protection / Restore Previous versions in Windows to try and capture some additional Windows VSS snapshots of changes to the database. However, you need to specifically turn it on for disks other than the primary OS drive (usually C:).
http://windows.microsoft.com/en-us/windows/previous-versions-files-faq#…
Yes, I know that for Oracle Database hot backup with Acronis we need 2 things:
1) VSS servise (Windows VSS servise + Oracle VSS Writer Service + Acronis snaphot backup via VSS);
2) Acronis Multivolume Snapshot option if Oracle Database live on few volumes (logical disks).
I want to khow follow: will be Acronis backup changed file if its creation date, modification date and size was not changed, but some blocks was changed? How Acronis will see that file is changed? Who talk him about it?
I can't answer that for you. I would contact Acronis support via chat and select the presales/licensing dropdown to see if technical support presales can answer your question. I realize you may have already purchased a license, but this will allow you to chat as a potential customer and they should hopefully be able to answer your question, or pass it to technical support to find out so that you can make an informed decision about purchasing any additional licenses or future upgrades.
Ok. Thank you very match for you answers in any case. :) I think you are right - it is time contact to Acronis support and I already have licenses for Acronis backup products.