topic Re: Configuring Dual or more SCSI cards in a System in General

Configuring Dual or more SCSI cards in a System

Matthew Murdock — Tue, 09 Apr 2002 19:36:09 GMT

Is it still necessary to have unique Scsi Ids for all Scsi host adapters in a System, whether P.c. or HP/ux Servers.

Re: Configuring Dual or more SCSI cards in a System

Sachin Patel — Tue, 09 Apr 2002 19:42:03 GMT

YES.
unless if you are using SAN then more then one system can see more then one tape/disk on same SCSI id.

i.e if you have tape id 6 then two system can see same tape drive.

Sachin

Re: Configuring Dual or more SCSI cards in a System

Matthew Murdock — Tue, 09 Apr 2002 19:48:35 GMT

So, then in a one system setup, each scsi controller has to have unique id's assigned to each scsi controller? I thought they did, but, I have forgotten why.
For example, in a X86 PCI based system, each pci bus has its own memory address. Why would the scsi host adapter need to have a unique id's?

Re: Configuring Dual or more SCSI cards in a System

Sandip Ghosh — Tue, 09 Apr 2002 19:57:59 GMT

By default SCSI Card is set for SCSI ID 7. Actually in a single SCSI chain all the ID's should be unique. Because SCSI devices are accessed by their ID and there address also defined by their SCSI ID. If you put multiple SCSI Adapter in a host all of them can be set as ID 7 but What ever the device connected through that adapter can't have ID 7.

Hope it helps

Sandip

Re: Configuring Dual or more SCSI cards in a System

pap — Tue, 09 Apr 2002 20:13:46 GMT

Hi It is immaterial thing to have common addresses for devices on different SCSI controllers.

1.The devices on the same SCSI controller card MUST nOT have same SCSI ID.

2. SCSI controller card has SCSI ID fix and it is 7.

3.for a particular machine, the SCSI adapters have different Instance number and hence the device address will be unique in all sense and hence there is no chance to have two same device address for different SCSI cards as well as devices among all SCSI cards.

4. Even if you are connected to SAN devices are allocated to different systems separately and hence the device address will be different for all the devices in Storage box.

-pap

Re: Configuring Dual or more SCSI cards in a System

A. Clay Stephenson — Tue, 09 Apr 2002 20:19:17 GMT

Hi:

The only requirement that each device on a single SCSI bus have a unique SCSI target ID. If you have 4 SCSI controllers on a single host then all can be set to the same id (usually 7 - the highest priority ID).

Occasionally, two hosts share a common SCSI bus
like this:
Host A SCSI Controller (ID 7) ----- Disk (ID 5) --- Tape (ID 2) --- Host B SCSI Controller (ID 6 - next highest priority).

Re: Configuring Dual or more SCSI cards in a System

Marino Meloni_1 — Wed, 10 Apr 2002 06:53:21 GMT

hi

--1 on one scsi host adapter, each device need to have unique id

--2 if you have two or more host adapter on one pc, rules 1 aply for each host adapter,

--3 if there is no bus sharing between hosts, each host is not dependent of each other

bye

marino