Use "-a" unless there's a reason you need to retain different permissions,
owners, etc..
"-c" is pretty much for those situations wherein you end up with identical
times and size but different content, and you need rsync to look inside
even though it appears unnecessary. As you have seen, slower than heck.
I don't know the nature of your filesystems, but I have a guess... on at
least one end is a network filesystem - NFS, SMB, NCP, AFS, something like
that. rsync has the "-W", or "--whole-file" option, which tells it that
there's no point in trying to read the file for changes - if it needs
transferring, just send the whole thing, because the LAN overhead will
waste the savings in WAN. Last I heard, -W was going to be forced if
either end was a network filesystem.
Wayne: did that ever come to pass?
Another thing: I haven't seen your actual commandlines and results, just
descriptions. Here's a set of sample runs. Note the difference between
"total size" and "wrote", and the fact that 29 or so bytes + 73 bytes nop
overhead doesn't come close to 470, or 6806.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
[EMAIL PROTECTED]
/home/cnwt99/work>sh doit
mkdir source
ssh disaster mkdir destination
dd if=/usr/local/admin/lib/locatedb of=source/Kfile bs=1024 count=1
1+0 records in
1+0 records out
rsync -av --rsync-path=/usr/local/bin//rsync source/Kfile
disaster:destination
building file list ... done
Kfile
wrote 1137 bytes read 36 bytes 782.00 bytes/sec
total size is 1024 speedup is 0.87
rsync -av --rsync-path=/usr/local/bin//rsync source/Kfile
disaster:destination
building file list ... done
wrote 73 bytes read 20 bytes 62.00 bytes/sec
total size is 1024 speedup is 11.10
date >>source/Kfile
rsync -av --rsync-path=/usr/local/bin//rsync source/Kfile
disaster:destination
building file list ... done
Kfile
wrote 470 bytes read 48 bytes 345.33 bytes/sec
total size is 1053 speedup is 2.30
rsync -av --rsync-path=/usr/local/bin//rsync source/Kfile
disaster:destination
building file list ... done
wrote 73 bytes read 20 bytes 62.00 bytes/sec
total size is 1053 speedup is 11.32
dd if=/usr/local/admin/lib/locatedb of=source/Mfile bs=1024 count=1024
1024+0 records in
1024+0 records out
rsync -av --rsync-path=/usr/local/bin//rsync source/Mfile
disaster:destination
building file list ... done
Mfile
wrote 1048813 bytes read 36 bytes 699232.67 bytes/sec
total size is 1048576 speedup is 1.00
rsync -av --rsync-path=/usr/local/bin//rsync source/Mfile
disaster:destination
building file list ... done
wrote 73 bytes read 20 bytes 62.00 bytes/sec
total size is 1048576 speedup is 11275.10
date >>source/Mfile
rsync -av --rsync-path=/usr/local/bin//rsync source/Mfile
disaster:destination
building file list ... done
Mfile
wrote 6806 bytes read 9024 bytes 6332.00 bytes/sec
total size is 1048605 speedup is 66.24
rsync -av --rsync-path=/usr/local/bin//rsync source/Mfile
disaster:destination
building file list ... done
wrote 73 bytes read 20 bytes 62.00 bytes/sec
total size is 1048605 speedup is 11275.32
[EMAIL PROTECTED]
/home/cnwt99/work>date
Thu Jun 17 16:11:23 MDT 2004
[EMAIL PROTECTED]
/home/cnwt99/work>date |wc -c
29
[EMAIL PROTECTED]
/home/cnwt99/work>
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Note also that the delta transfer doesn't happen on local transfers. Since
to do so would be to build a new copy of the file at the destination,
reading from both the source and destination files (once in entirety for
the checksums, again partially for the pieces kept and sent), then
deleting the destination, then renaming the newly created file to the
destination, it just does it in one read/write/unlink/rename...
essentially like the "-W" option.
Good luck.
Tim Conway
Unix System Administration
Contractor - IBM Global Services
desk:3032734776
[EMAIL PROTECTED]
Wayne Davison wrote:
>On Wed, Jun 16, 2004 at 08:26:33PM +0100, Gareth wrote:
>
>
>>I am making an extraordinary claim: rysnc seems to copy all my files,
>>not just ones that have changed or new files.
>>
>>
>
>Use either -t (preferred) or -c (slower). See also -a.
>
>..wayne..
>
>
Using -a, -t or -c (vvv slow!) does resolve the problem, but now I
notice that appends to text files results in the whole file being
transferred (as recorded by 'Total bytes written') rather than just the
9 characters I append to the file.
Surely this isn't the desired outcome?
Any information much appreciated.
Gareth
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