hardware raid 5 and software raid 0 stripe broke.

hardware raid 5 and software raid 0 stripe broke.

[Ken]

We have a Linux box running redhat 7.2   We have two hardware 
controllers in it with about 500gig's each.   They're raid 5.   We were 
using a software raid to combine them all together.   1 hard drive went 
down so we replaced it and now the system won't boot.   We have used a 
Knoppix boot cd to get into a linux system.   We can see /dev/sda1 and 
/dev/sdb1.   However, /dev/md0 cannot be accessed.   Is there a safe way 
to create the software raid from the cd to see if maybe mdadm on the 
original system got corrupt?   any help would be greatly appreciated.

Sincerly,
Ken

Re: hardware raid 5 and software raid 0 stripe broke.

[Neil Brown]

On Thursday May 11, Ken@4dcsi.com wrote:
> We have a Linux box running redhat 7.2   We have two hardware 
> controllers in it with about 500gig's each.   They're raid 5.   We were 
> using a software raid to combine them all together.   1 hard drive went 
> down so we replaced it and now the system won't boot.   We have used a 
> Knoppix boot cd to get into a linux system.   We can see /dev/sda1 and 
> /dev/sdb1.   However, /dev/md0 cannot be accessed.   Is there a safe way 
> to create the software raid from the cd to see if maybe mdadm on the 
> original system got corrupt?   any help would be greatly appreciated.

What booted off knoppix, what does

 mdadm -E /dev/sda1
 mdadm -E /dev/sdb1

produce?

How about
  mdadm -A /dev/md0 /dev/sda1 /dev/sdb1

NeilBrown

Re: hardware raid 5 and software raid 0 stripe broke.

[Ken]

Neil Brown wrote:
> On Thursday May 11, Ken@4dcsi.com wrote:
>   
>> We have a Linux box running redhat 7.2   We have two hardware 
>> controllers in it with about 500gig's each.   They're raid 5.   We were 
>> using a software raid to combine them all together.   1 hard drive went 
>> down so we replaced it and now the system won't boot.   We have used a 
>> Knoppix boot cd to get into a linux system.   We can see /dev/sda1 and 
>> /dev/sdb1.   However, /dev/md0 cannot be accessed.   Is there a safe way 
>> to create the software raid from the cd to see if maybe mdadm on the 
>> original system got corrupt?   any help would be greatly appreciated.
>>     
>
> What booted off knoppix, what does
>
>  mdadm -E /dev/sda1
>  mdadm -E /dev/sdb1
>
> produce?
>
> How about
>   mdadm -A /dev/md0 /dev/sda1 /dev/sdb1
>
> NeilBrown
>
>   
Thank you for your response Neil.   We got it up and running again.   I 
don't remember what we did though.   We've been going on no sleep all 
week trying to setup a new server and right before the old one crashed 
we were all ready to go home and take a little rest.

Thanks again.

--Ken