Albrecht Dreß <albrecht.dress AT arcor DOT de> writes:

> In my company, we plan to buy a set of new servers running Linux and  
> Windows, all connected to a SAN via Fibre Channel and a tape changer  
> (DLT or LTO), again with a fibre channel connection.  I wonder if it is  
> possible to use Amanda in this configuration.
>
> Accessing the SAN partitions shouldn't be difficult as they are visible  
> as simple block devices.  But what about the tape?  Is it simply a  
> /dev/st* for Linux, so it can be accessed the usual way?  And is it  
> possible to use the changer?  Anyone having experiences with such a  
> setup?

It should work that way. I use a Quantum PX502 with DLT-S4 and a
Quantum (formerly ADIC) i500 with LTO-4; everything directly connected
via FC (no FC switch).

The tapes are visible in Linux as /dev/st*, the changers as /dev/sg*;
so this is the same like SCSI.

(On the i500 we had to force the FC ports to "Loop Mode". So you might
need some FC experience to get the FC connection up, but I guess that
this is is a general problem with FC complexity. Don't be surprised
when some problem shows up.)

> An other question:  some vendors (e.g. ARCserve has a "CA ARCserve  
> Backup Storage Area Network (SAN) Option") seem to offer SAN backups in  
> which a backup software triggers a backup directly from the SAN to the  
> tape (I hope I got this correctly...).  Is this also possible with  
> Amanda?

I don't see a way to do this with amanda.

On the other hand I believe that this direct backup is pointless,
especially with amanda. I use gzip compression, and for this and other
reasons I use a holding disk. Without this I wouldn't get the bandwith
to keep the drive running. So the data must go through the amanda
server.

BTW: this means that there is no need to have the library/drives in
the same FC SAN as the storage. All data has to go through the amanda
server, so it is sufficient to connect library/drives to this host.

I have never seen the network to be a bottleneck. GigaBit Ethernet is
cheap.

        Sven