rsync - Jun 2005 - rsync process - writing to source file system

I've just recently started using rsync, and I have a question about how
rsync works in regards to writing anything to the source file system.

I am rsyncing between two systems and all seems to be working well.

However, on the source server we have another process running that seems to
be getting hung up whenever the rsync is occurring.

The source system has EMC Clariion disk arrays.  Several of the file systems
are set up to clone to another disk array.  When rsync is running (am
initially rsyncing some large data files across a WAN), the cloning process
gets hung up.

My theory is that perhaps rsync is writing/changing file attributes on the
source file system.  Since the EMC process thinks changes are being made, it
keeps trying to do the clone.  As data changes, the cloning continues.

Can anyone tell me if rsync makes any updates to the source file system?
And if so, is there a way that to get around this so that the cloning
process doesn't keep thinking that the data has changed?

TIA,
Diane

On Tue 28 Jun 2005, Diane Rolland wrote:
> My theory is that perhaps rsync is writing/changing file attributes on the
> source file system.  Since the EMC process thinks changes are being made,
it
> keeps trying to do the clone.  As data changes, the cloning continues.
> 
> Can anyone tell me if rsync makes any updates to the source file system?
rsync itself will not update anything on the source.
However, unixen will typically update the file's access time of any
files / directories / etc. that rsync accesses, perhaps that's your
problem. See if you can mount the file system "noatime" (that's
for
linux); check to see that no applications depend on access times though
(e.g. mail programs compare modification time and access time to see
whether there's new mail).


Paul Slootman