external tape drive and SA 6400

[Yayat]

Hi all,
I have proliant ml370g4 with the SA6404 array controller. Next I want to install external tape drive (VHDCI)to that server. The question is, can I attach the VHDCI tape drive to those SA6404 external port or should I install cable option kit to route integrated scsi port to external ?

[Oleg Koroz]

Probably more practically would be to use Integrated with Internal to external cable for Tape Drive and SA6400 use for Array configuration
Benefits:
Split for bus overload
Dedicated controller
If there will be some problem easy to troubleshoot

[Yayat]

I use array controller SA6400 with the expand module SA6400EM (SA6404), so I think the external port from the SA6400EM (port B1 and B2)is controlled by independent controller.
Regardless if something happen, does it work fine if I install the external VHDCI tape backup drive to the external port from the smart array controller ?

[Igor Karasik]

Use HP VHDCI SCSI internal to external cable option kit (P/N 333370-B21)
Don't connect tape to SmartrArray.
See "ML370 G4 cabling matrix"
ftp://ftp.compaq.com/pub/products/servers/proliantml370/ml370g4-cabling-matrix.pdf

[Yayat]

Thanks Igor, but what is the technical reason that I should not connect tape to smart array ? Anyway if I connect tape drive to smart array, what will happen ? I have had an SA6404 and my management want there is no cost again, it was expensive enough and still there are two unused external port. Any other sugesstion ? Thank a lot.

[Ruslan]

Yayat, trust to Igor :) You can find many post in this forum with issues when connecting tape drive to any RAID controller... Summary - never connect tape drive to RAID controller

[Igor Karasik · Accepted solution]

We use ML 370 G4 servers with SA6402 as well. We buy cable option kit and I think kit price is nothing vs. server price.
I even not tried connect our Ultrium 460 autoloaders to SA controller, because it is listed as not supported.
I think there are two main reasons exist why not connect tape to SmartArray (even if it will works):
1) Performance
2) Support. When you open case in Veritas for example (we use Veritas 9.1) one of the first questions will be "did you connect tape to SA controller or separate SCSI card?"

See "Summary" part of "HP Surestore and StorageWorks - How File System and Disk Configuration Affect Backup Performance with a DLT or Ultrium Drive" as well.
http://www1.itrc.hp.com/service/cki/docDisplay.do?docLocale=en_US&docId=200000081445430

[Basil Vizgin]

Attaching tape to SA possible, but not recommended. SA in this case work as "dumb SCSI emulator":)
Also SA did not support any of devices, that needed more then one SCSI ID, such as autoloaders/libraries.

[Yayat]

Thank Guys, your respons were very meaningfull.Thanks