On Mon, Jun 26, 2006 at 09:30:01AM -0700, Joe Donner (sent by Nabble.com) wrote:
> 
> That's an interesting suggestion, but I don't really follow on how to do this
> in practice.
> 
> Are you saying that you do daily backups just to disk, and only rely on
> monthly backups on tape which are then kept off-site?  Or do you mean do
> backups to both disk and tape - to disk for fast recovery and to tape for
> safekeeping?
> 
> I'd be very interested to understand this concept :)
> 

See docs at amanda.org, the wiki at zmanda.com, or your amanda docs
directory for more info on what is mentioned below.

Amanda has two capabilities relevant here.  The FILE:driver can
make space on a hard disk appear to be a physical tape drive
(and changer).  These are called virtual tapes, or vtapes.
I sometimes call real tapes "ptapes" :)

The RAIT capability (Redundant Array of Independent Tapes) can
send backups simultaneously to multiple tape drives, including 
vtapes.  These multiple drives can be configured to duplicate
each other (a mirror) if only two are used, or can be setup to
stripe the data across multiple drives for better performance
or capacity (Three striped 100GB drives would look like one
200GB drive).

Two scenarios seem suitable to what you have mentioned your
needs to be.

1. Dual configs, one a weekly archive that you run to physical
tape, only do level 0 dumps, not recorded.  Perhaps these are
done on weekends since you don't run other amdumps those days.
The second config would be nearly identical to whatever you are
attempting to set up right now, but with devices and changer
scripts that point to vtapes rather than ptapes.  The weekly
ptapes can be offsited, vaulted, rotated, whatever according
to their own needs.  They would have their own indexes and
logs maintained by amanda and independent of your daily config.

2. Single config using RAIT.  Your current config would have
a device that is a rait configuring two drives and changers
as mirrors.  One would be your current ptapes, the other vtapes.
You could immediately offsite copies of the days amdump.  Your
vtapes and ptapes would have to be kept in sync, ptapes rotated
back in as they have the same labels as the vtapes.  Recovery
could be from either.  Alternatively, if you need to archive
the ptapes, I think you can justs keep adding more ptapes with
new labels while relabeling the oldest vtapes to match.  This
retains the logs and indexes for the archived ptapes.

Scenarios 3,4, and higher are left to the imagination and
local requirements of the administrator.  Happy reading.

jl
-- 
Jon H. LaBadie                  jon AT jgcomp DOT com
 JG Computing
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