How to backup root filesystem the correct way....

[Steve Ringwald]

Daniel B. Thurman wrote:
> I am familiar with the unix dump and restore programs from my hey-dey
> and system admin used these for backing up individual filesystems to tape
> using these programs. But apparently, someone here told me that using
> dump/restore is not the preferred way and said that Torvald quoted
> that tar is better than D/R because it is not maintained nor current and
> may be fraught with failures.... and recommended that TAR be used.
>
> Geez....
>
> Well since I have a /boot problem, i.e. I blithely used a partition of /, including
> /boot and a seperate partition for swap (i.e. two partitions) of which my BIOS
> may eventually fail to see /boot, so I need to correct this mistake. But before I do,
> I need to backup my main boot drive by copying its contents to my 2nd drive
> so that I can recover if all hell breaks loose.
>
> So... 
>
> When I used /tar this way:
>
> tar zcvf root.tgz -C /<second-disk> /
>
> It appears that everything gets tarred up but there are many errors
> put out (such as sockets and such) but eventually after a long time,
> the final error at the end (whereever that may be) reports:
>
> tar: Error exit delayed from previous errors
>
> Hmm... cryptic as heck. But the bottom line is that there is no
> guarantee that all the files are being properly backed up.  Seems
> that this is very unreliable.
>
> Perhaps I should just use dump | restore to backup the filesystem
> to another filesystem (disk) would be better?  What is the reccommended
> way to backup the root disk to my second backup disk?
>   
Daniel,

Well, what I would do is boot off the rescue image on the install cd.

Partition the destination disk (I would use fdisk and mkfs.ext3/mkswap) 
then mount those partitions as /destination, /destination/boot, etc. 
Mount your src partitions in a src directory (or whatever) /src, 
/src/boot, etc.

Then go to the source directory and type:

find . | cpio -pmd /destination (or you could use rsync, or tar -cvp)

Then all you need to do is install grub on the destination drive, update 
your /destination/fstab, and delete /destination/{mtab,blkid}*.

Unmount the partitions, powerdown, pop out the source drive, and the 
destination should be good to go.

Hope that this helps!
Steve