rsync: failed to hard-link error message

[Brett Hamilton]

Dear Rsync,

I am seeing the following rsync error messages and I am wondering if it is 
a sign of trouble, expected behavior, or a bug:

rsync: failed to hard-link /Volumes/backups/vanguard/backup.0/dev/agpgart 
with dev/agpgart: Invalid argument (22) 
rsync: failed to hard-link /Volumes/backups/vanguard/backup.0/dev/apm_bios 
with dev/apm_bios: Invalid argument (22)
rsync: failed to hard-link /Volumes/backups/vanguard/backup.0/dev/atibm 
with dev/atibm: Invalid argument (22)
rsync: failed to hard-link /Volumes/backups/vanguard/backup.0/dev/audio 
with dev/audio: Invalid argument (22)
rsync: failed to hard-link /Volumes/backups/vanguard/backup.0/dev/audio1 
with dev/audio1: Invalid argument (22)
...etc...

Here's the situation:

I'm doing snapshot backups of up entire debian linux filesystems onto an 
external disk that is attached to my Mac Mini (running Mac OS 10.4.7). 
I've compiled the the latest version of rsync from source (2.6.8) on the 
Mac, and the linux boxes are running the version of rsync (2.6.4) that 
ships with Debian Sarge. I'm doing the backup over ssh and using the 
link-dest option to create the hard-linked snapshots.

I don't see this error when I make the backups from debian to debian (even 
with rsync 2.6.8 compiled from source on the linux box at the the 
receiving end). Also, on the Mac, I have the external drive mounted with 
"ignore permissions on the volume" turned off, so I have real unix 
permissions on the disk. I'm running rsync as root on both ends, in order 
to create all the permissions and user/groups structure etc.

To create the initial directory structure (works fine)

/Users/foo/bin/rsync -avH --numeric-ids --exclude=/proc --delete \ -e ssh 
root at vanguard:/ backup.0

To create the hard-linked snapshot backup: (produces the error message)

/Users/foo/bin/rsync -avH --link-dest=/Volumes/backups/vanguard/backup.0 \ 
--numeric-ids --exclude=/proc --delete -e ssh root at vanguard:/ backup.new

Thanks for your help. --Brett