Chris,

Thanks for your input.

I am using a 38 slot StorEdge C4 unit and one LTO2 tape drive.

See some answers below.

I just was looking to see if this is or could be done and if so how. With the 
virtual tape array maybe this will be mute. 

Robert


_____________________________________________________________________
Robert P. McGraw, Jr.
Manager, Computer System                    EMAIL: rmcgraw AT purdue DOT edu
Purdue University                            ROOM: MATH-807
Department of Mathematics                   PHONE: (765) 494-6055
150 N. University Street                      
West Lafayette, IN 47907-2067            
 

> -----Original Message-----
> From: owner-amanda-users AT amanda DOT org [mailto:owner-amanda-
> users AT amanda DOT org] On Behalf Of Chris Hoogendyk
> Sent: Thursday, May 14, 2009 12:53 PM
> To: amanda-users AT amanda DOT org
> Subject: Re: Amanda and dual tape libraries.
> 
> 
> 
> 
> McGraw, Robert P wrote:
> > I have a tape library (38) unit with one lto2 tape unit and one empty
> > tape slot.
> >
> > I need to speed up our backups.
> >
> > One option is to purchase a second tape unit but not sure how Amanda
> > works with a two tape drives. I searched the wiki for information but
> > did not get any hits.
> >
> > I am going to upgrade to the latest Amanda version so the version
> should
> > not be a problem.
> >
> > Can Amanda use multiple tape drives for a backup? I want to put
> complete
> > backup files on a tape and not strip the tapes.
> 
> If you are looking for speed and thinking of upgrading, then why not
> get
> an LTO4 drive to put in your library and switch to that? Assuming your
> backup system can drive it at full speed, that would be 3 times as fast
> as the LTO2 drive and would be able to read the LTO2 tapes. Of course,
> it would require transitioning to LTO4 tapes, but that's going to give
> you 4 times the capacity.
[McGraw, Robert P] 
I had looked into going to an lto4 but I am told by Sun that it is not 
supported on the C4. It does support the LTO3 but with the small increase of 
performance and the cost of LTO3 tapes I have decided to stay with the LTO2 for 
now.

> 
> Another option is larger holding disks (or a holding array), backing
> everything to there on its way to the tape.
[McGraw, Robert P]
I have 500GB and seem to be plenty. I am planning on upgrading to Amanda 2.6.1 
this month and start using the flush-threshold-dumped parameters. This should 
help. Also this summer I will have access to a 8TB array and will set up 
virtual tapes on this which will help.
 
> 
> Do your backup reports indicate that the taping speed is the
> bottleneck?
[McGraw, Robert P] 
My tape write speed is very close to the max for the LTO unit.

> 
> My library is AIT5, which isn't as fast as LTO. When a DLE is being
> written to tape, my system can drive the tape at full speed. However,
> the tape drive spends a lot of time idle, as the bottleneck on my
> system
> is traffic over the network and the busyness of the other servers that
> are being backed up. I have large enough spool drives that the backup
> activity is going to until it accumulates and is ready for taping.
> 
> 
> --
> ---------------
> 
> Chris Hoogendyk
> 
> -
>    O__  ---- Systems Administrator
>   c/ /'_ --- Biology & Geology Departments
>  (*) \(*) -- 140 Morrill Science Center
> ~~~~~~~~~~ - University of Massachusetts, Amherst
> 
> <hoogendyk AT bio.umass DOT edu>
> 
> ---------------
> 
> Erdös 4
> 
>