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SCSI LVD as a SE drive with RAID - Is SCSI drive positioning in an array important?

Okay, the question may seem cryptic so please allow me to explain.

All my Single Ended SCSI drives are now depleted (I just suffered a power interruption that took out my last three ST39173W drives and I'm forced to use a "newer" Seagate ST318436LW  LVD drive for replacements in my older servers with the SE jumper installed for Single Ended emulation.

My question is: Since the Seagate ST318436LW doesn't have termination; this drive cannot be the last drive in any of these arrays.  So in the event that I lose one of the last drives in the array, can I simply swap the positions of any of the other two working drives without adversely affecting the array?  

Example (3 drives in a RAID 5 configuration):
1 - Good
2 - Good
3 - Bad (last drive in array)

Since I cannot install the ST318436LW in position 3, can I reconfigure the positioning as so:

1 - Good
3 - Replaced with ST318436LW
2 - Good

Note: I'm just moving the drives into different bays, their ID's do not change.

So does it matter about position?  I doubting it's an issue but I thought I'd check with you folks.  

Yes, I know I can install an internal term. but I haven't found one yet (even on ebay).

Hopefully, all this hard ware will be upgraded soon but it's complicated because this is all old NT 4 servers (try making this stuff compatible with modern RAID hardware).  I'm opting to upgrade the s/w to Exchange 2003 and Windows 2003 but it's a very expensive proposition.

Thanks it's been a yucky night,
Shawn  
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Shawn Connelly
Asked:
Shawn Connelly
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1 Solution
 
Lee W, MVPTechnology and Business Process AdvisorCommented:
Why not just put a terminator on the end of the SCSI chain.  So the hard drive doesn't have a built in terminator.

If the disks are NOT in a RAID, then you should be fine.  If they are in a software RAID, I THINK they will be fine.  If they are in a hardware RAID, you will PROBABLY have issues.
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Shawn ConnellyTechnical WriterAuthor Commented:
Thanks for your response, leew.

It hardware RAID (5).  I don't believe it's possible to do software RAID level 5 (but I think you are referring to RAID in general).
Shawn
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Lee W, MVPTechnology and Business Process AdvisorCommented:
Sure it is.  Windows will do it.  I'm pretty sure Linux will do it.  I used to run an 8 disk SOFTWARE RAID 5 under NT4.

What RAID controller are you using?  

Besides, I think those drives DO have a termination option - see http://www.seagate.com/support/disc/scsi/st318436lw.html (Note the bottom jumper configuration).  Otherwise, I'd just add a terminator to the end of the chain.
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Shawn ConnellyTechnical WriterAuthor Commented:
Hey, I've been on holidays. Though I appreciate everyone's input, my question was never *definatively* answered.

leew: This drive doesn't have internal termination. Quote from manual, "LW, LWV, LC, and LCV models do not have internal terminators or any other way of adding internal termination on the drive. You must provide external termination when termination is required. This is normally done by adding an inline terminator on the end of the cable."

Unfortunately, with this particular computer it will be difficult to add a terminator to the end of the SCSI chain.

I stand corrected on software RAID 5 (or better).  I looked at some benchmarks and today's CPU's really perform well with software RAID 5.  It really makes me wonder if it's really neccessary to purchase dedicated RAID hardware (at least for a smaller company - under 50 clients).

I'm fine with the moderator's decision...after all, leew was the only one to bother responding.

Shawn
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Lee W, MVPTechnology and Business Process AdvisorCommented:
I'm a little fuzzy on the terminator room at the end.  Internally, are things THAT cramped that you can't use a cable with one more connector on it and attach something like this:
http://www.pccables.com/01113.htm
to the end of it?
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