Which backup apps verify the checksum of what they've written?

Question

I've been using TeraCopy and DirSyncPro for moving & syncing large file sets (1.5TB) between 3 locations- a SMB NAS share, a local drive & an external.

Neither of these solutions are quite right though.

TeraCopy will test SHA1's on everything after the entire operation is copied, but only reports there being an error rather than doing anything about it, ie. re-copying it.

DirSyncPro will do some kind of checksum after each file before it moves on to the next. And again, only reports errors rather than fixing them.

DirSyncPro allows for 'larger', 'newer', and 'modified' conditional copying, as well as deleting content that exists only on the destination side.

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The problem with TeraCopy is that when it sees a conflict it's only option is to skip or overwrite, without regard to if the source is larger than the destination, or if the source has been modified since having been copied to the destination last.

I can't depend on DirSyncPro because sometimes when it scans the source directory it'll only process 12k files rather than all 80k that are there.

This has happened twice, the first time resulted in data loss and I was saved by having another good copy elsewhere. This time I caught it before it started deleting what it thought shouldn't be there, and thus am here searching for another solution.

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Since I'm not seeing many backup apps addressing the issue of write corruption, I wonder if the problem is so rare that maybe I shouldn't be concerened.

I once lost some photos from my late mother's computer due to an archive becoming corrupted during a copy, have been hypersensitive to checksums ever since.

EDIT:

For the sake of whoever happens across this later- I've since found a commercial app called SyncBackPro, which does check it's work. So far so good after a few runs.

Answer 1

For the sake of whoever happens across this later- I've since found a commercial app called SyncBackPro, which does check it's work. So far so good after several runs. I'm quite happy with it.

Another I found was ws_ftp, which checks it's work as well. Transfer speeds between 2 remote hosts was too abysmal to keep it around though.

Answer 2

I use CrashPlan for backups on my home machines.

One of the features that I like about CP is that it periodically verifies the integrity of the backup, and will automatically re-backup any files that it finds affected by problems.

For reference

• Automatic daily background backups
• Can backup to other computers (LAN) or friends (over the internet) for free
• Pay per month for backup to CrashPlans own servers
• Pay for upgrade to CrashPlan Pro for real time backups

Note: This is a backup application, not a directory synchronisation one. The backup format is encrypted and versioned - but not browsable through the file system.