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rational backup strategy

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Hallo,

caused by some troubles with backup and recovery of disk images of my notebook computer with true image, I gradly had some proposals for a rational backup strategy. I used since last week one external backup disk for arconis backups, which fails during a power cut on recovery of an image with true image. Consequent after power fail and a defect hard disk sector (Bad LBA) on external backup storage disk, on acronis image file in backup chain was also corrupt. I had to restore - fortunately I had one, which was valid - a three days older full backup, but all following incrementals were lost. I read here in forum, that it is usefull to use two hard disks for backup - alternating each disk for backup. Can this minimize the risk of a failed recovery?

Is it better to make always (i.e. each week) full backups or could I use also incremental backups? How long might the backup chain become, to mimimize the risk of failed recoveries by an unvalid incremental backup element or by an failure on the hard disk. Or is it better to use differential backups? From time to time I had to restore the state of my computer installation to an earlier state.

Helmut F.

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Two backups drives, rotated, naturally provide greater security and redundancy for your system and data. Even if you system drive and a backup drive fail, are stolen, are destroyed by fire, you'd still have the other backup. That's why a system of rotating backups ideally involves storing one off-site.

You can make incrementals. However, as you found, if one incremental in the chain is unrecoverable, no subsequent incrementals in the chain will be recoverable. Keep the incremental chain relatively short.

Yes, you can use differentials. With a differential, each one is only one chain link away from the original full backup.

Really the two reasons to use incremental or differential are: disk space; and speed. If you have plenty of backup storage, and don't mine backups taking longer, you could do all full disk backups if you like. Almost all my backups are full disk backups; I rarely do incremental or differential. it takes somewhat longer, but I know that every backup is "stand-alone" and I don't risk any one being unrecoverable just because some other file is unrecoverable.

I also supplement my ATI backup images with file-based backups, especially of my 400 GB of music. I used to use MS SyncToy, now I use MS Robocopy.

thank you tuttle,

robocopy I also use for mirroring some special folder to an separate external disk. Additional I syncronize folder "Documents" and "Downloads" with true image sync to a second external hard disk. A new drive for rotated backups will come at the end of the week.

In past I always made incremental backups, but I will try differential backups, which needs more time for backup, but each differencial is it own with the full backup, so a corrupt differential backup does not end in a loss of the whole chain and restoring differentail backup is quicker than incrementals. The disadvantage of differentials is, that I don't have complete image snapshots, but only one will be lost in case of a corrupt diffential.Is this right?

A differential depends only on the original full backup.
An incremental depends upon the previous backup on which it is based, whether full or incremental. An incremental chain can conceivably become quite long.
A full backup is complete and depends on no other file.