I did a backup using the tar command.

Here is the command and the output.
-------------------------------------------------------------------

[root@localhost /root]# /bin/tar -czf /mnt/ronsan02/backup.tgz /
/bin/tar: Removing leading `/' from member names
/bin/tar: /proc/kcore: File shrank by 311647744 bytes; padding with zeros
/bin/tar: /proc/2/exe: Cannot readlink: No such file or directory
/bin/tar: /proc/3/exe: Cannot readlink: No such file or directory
/bin/tar: /proc/4/exe: Cannot readlink: No such file or directory
/bin/tar: /proc/5/exe: Cannot readlink: No such file or directory
/bin/tar: /proc/6/exe: Cannot readlink: No such file or directory
/bin/tar: /proc/7/exe: Cannot readlink: No such file or directory
/bin/tar: /proc/8/exe: Cannot readlink: No such file or directory
/bin/tar: /proc/73/exe: Cannot readlink: No such file or directory
/bin/tar: /proc/2074/fd/3: Cannot stat: No such file or directory
/bin/tar: /tmp/.font-unix/fs7100: socket ignored
/bin/tar: /tmp/.X11-unix/X0: socket ignored
/bin/tar: /tmp/ksocket-root/kdeinit-\:0: socket ignored
/bin/tar: /tmp/ksocket-root/klauncherPfMg8b.slave-socket: socket ignored
/bin/tar: /tmp/.ICE-unix/1984: socket ignored
/bin/tar: /tmp/.ICE-unix/1150: socket ignored
/bin/tar: /tmp/.ICE-unix/1902: socket ignored
/bin/tar: /tmp/mcop-root/localhost_localdomain-07c7-3b8dc161: socket ignored
/bin/tar: /dev/log: socket ignored
/bin/tar: /dev/gpmctl: socket ignored
/bin/tar: /home/ronald/.kxmlrpcd-socket-pfGTfP: socket ignored
/bin/tar: /mnt/ronsan02/backup.tgz: file changed as we read it
/bin/tar: /root/.kxmlrpcd-socket-rPN6jj: socket ignored
/bin/tar: Error exit delayed from previous errors
[root@localhost /root]#
------------------------------------------------------------

What do you think? Did I get a viable backup?
How do I check this?
Is there a better way?

The output from this program is cryptic and not understandable.

I would guess that your tar files is good. Most the the files that tar did not like are special files that he can't really handle anyway.

What I usually do to get around taring up /proc, /dev and /tmp is specify the directories I want on the tar file on the command line.

tar -cvf /tmp/backup /home /usr /var /etc /whatever

What do you know about cpio taper script or amanda as backup programs. Are any of these worth looking into?
How about restoring a single file using tar? How does one do this?

I have tried some backup programs, but I always seem to fall back on a simple tar command. You should keep one thing in mind when creating backups. Keep it as simple as possible. You don't want to have to struggle to get your backup restored when the time comes. Compression, fancy scripts or formats always cause problems in the end. It is likely that you will not even be restoring to the same hardware, nor with the same tape drive as before.

Tar is all I use.

Gary

Oops..

This will extract as:

./full/path/to/file