View Full Version : SCSI RAID connection query

09-07-2001, 07:03 AM
I am trying to set up a SCSI RAID on an Apple 7350 server. I have a redundant RAID that I have been given that was previously used on an old 133 Mhz PC, with an accelerator board, for video work. It is a two disk array that I would like to mirror. The case has the manufacturers name 'Team 4'. My query is; the drive appears to have two scsi connectors on the back with two ID numbers. The previous machine it ran on had two separate cables going in to the RAID. This leads me to think that there is no way to chain the two together. Does anyone out there know how I can hook this up to my Mac so that it sees both drives. I have initialised both disks separately, using Apple RAID, but can see no way of setting the raid up so that my machine sees both drives.
Any help appreciated

09-07-2001, 11:01 AM
It sounds to me like your external RAID is dual channel. Why there are only two and not four external connectors is probably because the SCSI terminators must be inside the case. To get both drives to show up on your mac you have a few options.

1 - Get a dual channel SCSI card and connect one drive to each channel
2 - Get two single channel SCSI cards and connect one drive to each card
3 - Modify the RAID case so that you have external access to both ends of each SCSI bus and place a jumper between the two busses, turning it into a single bus. (You will have to check ID settings on the drives to make sure they don't conflict.)
4 - Modify the RAID case by replacing the two internal cables with one, turning it into a single bus case. (You will have to check ID settings on the drives to make sure they don't conflict.)

If you don't mind cracking the case open I suggest going for option 4, it probably wouldn't be terribly difficult and would fix your problems. Options 1 and 2 will offer better theoretical performance, but depending on what kind of SCSI it is this may or may not be an issue.

- Chris

09-07-2001, 06:57 PM
The fact that you initialized the drives individually shows that you've already verified that the connectors go to the individual drives. If I were you, I'd open the drive to see if there's someway to re-cable the box for single channel use. The simplest route would be to use the cable setup from another drive package.

It would give you little benefit building a two channel RAID out of one dual channel SCSI card. The overhead of switching from one channel to the next would eat up the benefit of the RAID.

09-09-2001, 08:48 AM
Thanks everyone for replying. On Monday morning, I will have a go at sorting this. I must admit I did crack open the case and have a look!

I have a spare internal SCSI Cable so I think a couple of female to female adaptors on the ends, to link up to the external connectors, and I will try making the drives on the same chain.

The drives are IBM, and have jumper guides on them. I will try and sort the termination. If I have any problems, you may hear from me again.



10-10-2001, 02:49 AM
Just a quick thankyou, finally got around to sorting the RAID out, and so far, everything is running smoothly. Cheers for the pointers.