Conference ssag::ask_ssag

>I have no experience to configure TL812 and don't know much
>about the characteristic and spesification of TL812.
>But I will configure 2 units TL812 soon.

	The TL812 is a tape library with 48 spaces for storing
	tape cartridges, 4 TZ88 tape drives and a four element
	Import/Export element.  The box contains five SCSI
	devices; the tapes and the media changer.  It has four
	SCSI busses, so you can configure 1 drive on each bus,
	2 drives on two busses, all four drives on a single bus,
	etc.  The robot must always be on bus with one of the
	drives.  The changer supports a bar-code reader that
	will read bar-code labels on the tapes.
    
>Actually they already have 2 units TZ875 autoloader and 1 TLZ7L
>autoloader.

	Then they're already familiar with setting up a media
	changer.  The only notable difference between the changer
	on the TL812 and others is that the media changer on the
	TL812 is a separate target at LUN 0.  The other devices
	make the changer a different LUN on the same target as the
	tape drive.
    
>They expect that TL812 has a better specification than another
>backup device they have. I mean the don't want to reconfigured
>the scripts, and application that they already used for backup
>system.

	They'll have to make some changes because the name of the
	media changer device will change.  The number of available
	cartridges will change and they'll have one more tape drive
	than before.  It may not require substantial changes to
	their scripts, but it will require some changes.
    
>The main point that they always ask me is does TL812 can automatic
>ally unload TK88 and reload new one when they need to backup their -
>data that more than the capacity of the media..?

	No, but you can get software that will.  NSR with the right
	jukebox license will do this.  I don't know what they're
	using for the SAP backups, so getting tape changes there
	may take some work.  Unlike the TZ875 and TLZ7L, an mt(1)
	offline command to a drive won't cause the library to unload
	the current tape and load the "next" one.  They should be 
	getting a copy of MRU with the library, which they can use
	to make tape changes, but coordinating with whatever is
	doing the writing and MRU could be hard.

	They may want to see if Networker (NSR) offers an add-on
	module that will do SAP backups and use NSR for media
	management.

    
Thanks for your quick reply 

> It has four SCSI busses, so you can configure 1 drive on each bus,
> 2 drives on two busses, all four drives on a single bus,etc.
> The robot must always be on bus with one of the drives.
  

     I just got the manual for TL812 that consist of :
     - Operator's Guide
     - Diagnostic Software User's Manual
     - Facilities Planning Installation Guide
   
     I've read it but not all. But I'd like to find out more about SCSI
     wire configuration. Based on the manual that it can be configured it 
     as single-wire, two-wire, three-wire, and Four-wire SCSI configuration.

     And I think they will configured their system as four-wire configuration.
     But I still confused about it. I mean, if they configured TL812 using four-
     wire SCSI, how about robotics controller software..?
     Could they installed it on all system that connected to TL812..?
     and could they managed the Tl812 from all system that connected to TL812..

     I just thought that if I configured it as two, three, or four wire configuration,
     I could managed it from the system that connected to TL812 by installing robotics
     controller software.

     
     rgrds
     daivc::ramadoni

	The usual reason for using multiple SCSI busses with something
	like the TL812 is performance, NOT having drives connected to
	multiple systems.  Usually, all the drives are connected to
	the same system and the problem of robot control is trivial.

	If the customer wants to spread the busses out over multiple
	systems, he will have to check for each software package that
	could control the robot whether it can operate in a networked
	fashion.  The robot is only on one of the busses.  Any medium
	changer commands needed by the other hosts will have to go through
	that host.

	With suitable permissions you could do it with rsh and MRU
	between UNIX systems:

		rsh robot-system robot ...

	Other media management software may not have a clue how to
	control the other drives.

> The usual reason for using multiple SCSI busses with something
> like the TL812 is performance.

   That's right. The issue is about performance. In this case they
   will using AS1000 for their Backup-server. There is a limitation 
   of PCI slot on AS1000. It's impossible to configured it as four-
   wire configuration I think.
 
   Actually I'm going to configured two-wire configuration for testing
   tommorow. I'd like to find out about management of TL812.
    
    but if I have to configured it as four-wire configuration on single-
    system (in this case AS1000), what do you think about the specific-
    ation of the backup system such as memory size, cpu type,etc..?
    
    BTW, many thanks for your help..
    
    rgrds
    daivc::ramadoni
      
    

	If this is going on a 1000, 2 drives/bus (2-wire config)
should not pose much (if any) performance problem since the drives
are rated at 3MB/sec. (compressed)... However, going to a single-bus 
config might see some performance degradation...

Joe