Re: [rdiff-backup-users] Any Thoughts on Why rdiff-backup Is So Slow?

[Robert Nichols]

On 03/13/2012 03:25 PM, Robinson, Eric wrote:
> Using rsync to copy a local directory to a remote computer takes a 67 seconds.
> Using rdiff-backup to backup the same local directory to a remote computer takes
> 11 minutes. Why does rdiff-backup go so slow? Does the number of increments on
> the remote computer influence the speed? We keep 30 previous daily increments

The number of increments is irrelevant since rdiff-backup is working only
with the most recent version (the mirror).  What will make rdiff-backup
slower than rsync is the need to calculate and store the reverse diffs.  In
particular, when there is a large volume of newly deleted files it can take
some time to compress and store the old, now deleted files.  I see this
mainly when there has been a Linux kernel update that caused an old kernel
version to be uninstalled.  That's a lot of files that need be compressed,
stored in the increments directory, and removed from the mirror, whereas
rsync would just need to remove the old files.  Deleting a 4GB ISO image is
be another example of something that would be very fast for rsync but quite
time consuming for rdiff-backup.

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Bob Nichols     "NOSPAM" is really part of my email address.
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