Extremely large incremental backups (auto-defrag disabled)
I have a dataset about 550GB in size that I back up weekly using the incremental scheme.
The first full backup was about 525GB, as expected. However, every incremental backup after that is at least 190GB, sometimes over 220GB. This occurs even if I perform two incremental backups back-to-back (i.e. there is no way I am generating 200GB of modified data in that time).
Why are the incremental backups so huge? I have auto-defrag disabled for all drives being used, so it can't be that.
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It's a disks & partitions backup of my C:\ (a 120GB SSD) and A:\ (a 500GB ReFS Storage Space, two 500GB drives mirrored). The backup destination is an external 3TB drive.
I don't use Outlook, so there are no .psts or other large files that could cause issues. I do have VMs, but their virtual drives are the individual file type (and I haven't touched them in a month anyway, so that can't be the issue). In any case, doesn't Acronis back up only the modified blocks?
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I think this is because of the Windows Storage ReFS drive. I bet you won't see this problem if you exclude that disk from the backup.
Is this a Windows Storage (ReFS) set up disk or is it a ReiserFS file system disk?
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Mark Eldridge wrote:doesn't Acronis back up only the modified blocks?
Honestly, I'm not sure, I would have to test a large file like a PST to see. It is specifically stated that Nonstop backups do have this functionality, but I cannot find a reference for it being applied to other backup jobs like full, incremental, or differentials.
Using Acronis Nonstop Backup
You may think that at these backup rates the storage will fill in no time. Do not worry as Acronis True Image 2016 will back up only so called "deltas". This means that only differences between old and new versions will be backed up and not whole changed files. For example, if you use Microsoft Outlook or Windows Mail, your pst file may be very large. Furthermore, it changes with each received or sent E-mail message. Backing up the entire pst file after each change would be an unacceptable waste of your storage space, so Acronis True Image 2016 backs up only its changed parts in addition to the initially backed up file.
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Pat L wrote:I think this is because of the Windows Storage ReFS drive. I bet you won't see this problem if you exclude that disk from the backup.Is this a Windows Storage (ReFS) set up disk or is it a ReiserFS file system disk?
I thought the ReFS might be the problem, but this is a folder backup (only with me selecting the drives as folders), so I thought the filesystem would be transparent to Acronis at that point.
It's ReFS, not ReiserFS.
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It doesn't seem to matter if it is a full disk or folder backup - incrementals are not supported on ReFS drives. Well, technically you can, but it will basically be a full each time - even though Acronis will attempt an incremental...
https://www.backupassist.com/blog/support/incremental-backups-and-windows-server-2012/
"The backend process that BackupAssist uses to run incremental backups in Windows Server 2012 has not changed. However, incremental backups will not occur on a Resilient File Systems (ReFS). The ReFS is a new file system that has been introduced with Windows Server 2012, and can’t be read by previous versions of Windows, such as Windows Server 2008.
ReFS can still be backed up and restored as normal, but Windows Server 2012 will ignore the incremental setting for ReFS volumes and a full backup will occur."
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Great. I guess I'll look elsewhere then, I can't afford to be doing full backups every time.
Thanks for the help!
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Sorry for the bump, but does anyone know if this has been fixed for Acronis 2017? I'm considering getting it but would like this issue to be fixed first.
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Mark, I have not seen any mention for ReFS Storage Spaces in any posts about ATIH 2017.
I would recommend making a backup of your current system and then downloading a 30-day trial copy of ATIH 2017 which should give you the time you need to be able to test this issue for yourself to see if you want to purchase the product or not.
You should be able to download the trial from the main Acronis.com web pages.
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