Rsync speed over network.

[jw schultz]

On Tue, Nov 12, 2002 at 11:03:34AM +0200, Mozzi wrote:
> 
> Haile the list ;-)
> 
> I am new to this list and this is my first post so grretings to all and 
>   nice to meet you.
> 
> I am setting up rsync here to do a MASSIVE copy from one machine to the 
> other.
> I am moving mail servers so I must copy /var/spool/mail/ over to the 
> other machine.
> I understand and have used locally the copy methods(manpage is good) but 
> I need to ask what will be the fstest possible way to copy over the data 
> from one machine to the other

dd the device (unmounted) over an unencrypted network pipe
would be the fastest possible.  Also would be a poor choice.

> I have setup two gigabit ethernet cards with a crosover cable and used a 
> private ip address range (10.0.0.1) between them so security is not an 
> issue.
> I have about 80 000 mailfiles giving a total of about 50Gigs, obviousely 
> downtime has to be kept to a minnimum.

If the network is slower than disk here is what i'd suggest:
Use anything to copy, rsync or whatever, in advance
preserving timestamps etc.  That will get most of the data
there.  At the cutover time quiesce both ends and rsync.

If the network is faster than disk (very likely) just pump
the data over.  rsync via rsh is a good way as are others
and rsync will do a checksum on both ends to confirm
correctness.

> 
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Hear hear!

-- 
________________________________________________________________
	J.W. Schultz            Pegasystems Technologies
	email address:		jw at pegasys.ws

		Remember Cernan and Schmitt