[BC] Partial recovery

[Cowboy]

On Friday 27 March 2009 07:47 pm, Harold Hallikainen wrote:
>  
>  >
>  >  For me, rsync is a daily thing, so the "bare metal" is unnecessary.
>  >
>  
>  rsync just copies over the files,

 Depending on the options.
 rsync is a more sophisticated cp capable of copying to either the local
 disk, another local disk, a network drive, or an off-network machine so
 long as a tcp route is available.
 It can preserve meta data, or not as you choose, compress, decompress,
 all sorts of things. As such, it can take a bit of a learning curve to fully
 exploit the possibilities.

>  though, and not the structure of the 
>  drive (partition tables, etc.).

 The structure of the filesystem, yes.
 The geometry of the drive, no, and you really don't want that.
 Partition tables are specific to a drive type, and are not transferable.
 You CAN transfer a partition table, but you WILL have problems if the
 cylinder boundaries do not align, or ( especially on very large disks )
 the access mode is different.

>  If you lose a drive and have only an rsync 
>  backup, it seems that you'd have to install the OS on the new drive, then
>  use rsync to copy everything back.

 No. Merely install the boot files, and run the loader. 
 ( only to write the MBR bootable ) Everything else is done.

>  With the bare metal backup (drive 
>  image), I can get back to my last backup with no installs. Just copy the
>  image back.

 Whereas I merely boot the image disk. It then becomes the main,
 and I buy another backup disk.
 A generation or so behind, but constantly upgrading the hardware
 this way as a consequence.

>  g4l does, however, require that the system be offline so the 
>  disk is not changing on us as we make the image.

 rsync does not, though what's copied will be what it was
 at the moment that file was read.

>  That's why I only do it 
>  once a month overnight. As I mentioned, I do rsync about weekly. I'll
>  probably do it more frequently once I get my backup server reconfigured

 cron is your friend.

-- 
Cowboy