# SCSI RAID-10 Trying to add spare w/o luck



## Chris516 (Jun 5, 2009)

I have a RAID-10 on an Adaptec 39320A Host Adapter using SCSI IDs' 0-3. SCSI ID#2 is not found in the RAID, but as a 'Spare' hard drive.

The RAID's status is 'Degraded'. When I try to add drive to the RAID, it still lists it as, an individual drive.

How can I add, the drive in question?


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## MALCO.New.York (May 29, 2009)

Chris516 said:


> I have a RAID-10 on an Adaptec 39320A Host Adapter using SCSI IDs' 0-3. SCSI ID#2 is not found in the RAID, but as a 'Spare' hard drive.
> 
> The RAID's status is 'Degraded'. When I try to add drive to the RAID, it still lists it as, an individual drive.
> 
> How can I add, the drive in question?



You might garner a better answer asking this sort of question on a Techie Site!


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## skipjack (Aug 15, 2008)

What size are the drives? AFIK, a RAID 10 is merely a RAID 1 nested inside a RAID 0 (or is it the other way around? It's been years since I've done RAID). 

If I understand correctly.. you'll need to stripe two drives on RAID 0 and then mirror those onto the 3rd drive using RAID 1. Drive size is important here.. the RAID 0 drives have to fit in the RAID 1 drive. Or I _suppose_ you could do it vise versa with one drive mirrored to two striped drives... either way, you need one drive able to fit the two other drives' content.. spacewise.

Otherwise, the SCSI controller might limit the size of the RAID to what can fit... perhaps that's why you're getting the "degraded" message? 

Like I said, it's been years since I've RAIDed anything... and that was either 1 or 0.. not both. So, I might just be giving you bad info all around. 


[EDIT:] Yaknow what.. reading a little more into RAID10... your controller may require an even number of drives (say, 4) to properly mirror and stripe. I'm not sure RAID10 can be done with 3.


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## Chris516 (Jun 5, 2009)

skipjack said:


> What size are the drives? AFIK, a RAID 10 is merely a RAID 1 nested inside a RAID 0 (or is it the other way around? It's been years since I've done RAID).
> 
> If I understand correctly.. you'll need to stripe two drives on RAID 0 and then mirror those onto the 3rd drive using RAID 1. Drive size is important here.. the RAID 0 drives have to fit in the RAID 1 drive. Or I _suppose_ you could do it vise versa with one drive mirrored to two striped drives... either way, you need one drive able to fit the two other drives' content.. spacewise.
> 
> ...


My AHA-39320A Host Adapter supports RAID 0,1 and, 10. Before I had the problem with ID# 2, it was working fine. Now, The drive I put in place of the bad drive(on ID# 2), shows up in the Host Adapter BIOS as a separate drive. When I try to add it to the RAID, it won't let me.:furious:


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## DangerMouse (Jul 17, 2008)

maybe the drive needs to be jumpered? or go to cmos and id it there?

DM


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## tribe_fan (May 18, 2006)

What this a clean drive ?

I have had to low level and initialize a drive before it was allowed to be used as a replacement in a RAID pack. 

The drive must also be the same exact size or bigger that the replacement.

Are you using the BIOS utility, or Adaptec Storage Manager ?


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## Chris516 (Jun 5, 2009)

tribe_fan said:


> What this a clean drive ?
> 
> I have had to low level and initialize a drive before it was allowed to be used as a replacement in a RAID pack.
> 
> ...


The drive is the same as the drive on ID#3

The drive on ID#'s 0 n' 1 are the same as eachother, but different than the drives on ID#2 n' 3. Likewise, The drives on ID#'s 2 n' 3 are the same, but different from ID#'s 0 n' 1.

The only absolute similarities across the board are:

1. The form factor of all the drives
2. The interface
3. The size


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## tribe_fan (May 18, 2006)

Did you "low level" the replacement drive ?

Can you describe the process - 

On the Adaptec Controllers that I am familiar with - you don't add it to the pack - but select the pack and select "rebuild".

Are you using the Adaptec Storage Manager - this is software that gives you the ability to manage the Controller. Its usually free from Adaptec.com.


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## Chris516 (Jun 5, 2009)

tribe_fan said:


> Did you "low level" the replacement drive ?
> 
> Can you describe the process -
> 
> ...


I used the software that came with the card. I had to download the Adaptec Storage Manager separately from the Adaptec website.


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