rsync freezes when copying several million files

Robert Siemer Robert.Siemer at
Tue Aug 22 09:13:45 GMT 2006

> >I'm using Dirvish to backup my servers. For those who haven't heard
> >about it it's sort of "front end" for rsync making a copy of the files
> >for the first backup, and then copying modified files and hardlinking
> >unmodified files every day.

dirvish is using the services of rsync to let the hardlinks get done.
Not much of dirvish's tribute.

> >I have 600 000 files, and I'm keeping 120 backups on disk. Files are not
> >changing too much, I have something like 120 GB of data and 180 GB of
> >backup.
> >That is roughly 600 000 files with 100 hardlinks on each, so 60 000 000
> >files.

That are 600 000 files and 600 000 hardlinks to consider. The 119 older
backups don't even get a look.

> >By the way what is the memory usage on the receiver side ?
> >For the first rsync there is no files receiver side, so it's no problem.
> >But after that first rsync memory usage will be the same on sender and
> >receiver side, as they'll both have to create their file list. Am I right ?
> You could mount the other side (NFS, iSCSI etc., but that depends on the 
> connection you have), so that there would be only one rsync instance 
> running?

Mounting the remote side local contradicts a little the use of rsync. If
rsync decides to compare a file, it _reads_ it to get it's checksums.
The remote rsync instance would send only the checksums over the
network. In a network mounted scenario the whole file is transfered by
the filesystem.

The only advantage that stays is when rsync dicides to assume the files
equal (same size, modification time, etc).


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