MSL4048 with three Ultrium 920 drives

[abcxyz]

Thanks Curtis,

So will the below config be correct:

Drive1 (Master Drive) - ID 4
Drive 2 - ID 5
Daisy chain the above two drives

Drive 3 - ID 4
Connect directly to HBA

The Manuals do not mention these points.

Appreciate your assistance.

[abcxyz]

Another Question,

Incase the Backup is started on all the three drives simultaneously in this configuration using Data protector Express,Should it work.I mean would the backup start immediately on all the three drives.What happens here is the Disk Agent goes into a Wait state for long on one of the drive and has to be aborted.

The User wants the backup to happen simultaneously on all the drives.

[Curtis Ballard]

The documentation does talk about how the SCSI bus should be configured in multiple places. One of them is in section 8a of the getting started guide.

That section states that only one 920 drive should be on a bus. The way you have it configured now with two 920 drives on a bus will probably work but I would never recommend it. Make certain you run L&TT and pull drive support tickets then check the negotiated transfer rate to make certain the drives can actually run Ultra 320 with this configuration.

Is there something about this section that is confusing? We could improve it in future releases. I have copied it here:

Follow these general guidelines when planning the parallel SCSI configuration:
â ¢ The Ultrium 960 and 920 tape drives are Ultra320 SCSI devices. Only one Ultrium 960 or 920 tape drive should be put on an Ultra320 SCSI bus. Putting an Ultrium 960 or 920 tape drive on a slower bus or putting two drives on the same bus may degrade performance.
â ¢ The Ultrium 448 tape drive is an Ultra160 SCSI device. Only one Ultrium 448 tape drive should be put on an Ultra160 bus. Up to two Ultrium 448 tape drives can be on an Ultra320 bus.
â ¢ Avoid putting the Library on the same SCSI bus as a disk drive or SE device. The Library has an LVDS SCSI bus. It is NOT compatible with a standard differential (Diff) or High-
Voltage (HVD) SCSI bus.
â ¢ The default SCSI ID for all full-height tape drives is 4.
â ¢ The default SCSI ID for half-height drives is 4 or 5, depending on the drive bay as shown below.

[Curtis Ballard]

On your other question about starting a backup on all of the drives at once:

Yes - DP should be able to start the backup on all drives at once. I'm not a DP expert though and can't say what might be configured wrong. That question might need posted to the DP forum.

[abcxyz]

Thanks Curtis !

I had not gone through this documentation.I will be checking on all aspects and would Post the results here.