Reconstructing RAID-0 to RAID-10 using omconfig

Harald_Jensas at Dell.com Harald_Jensas at Dell.com
Sun Jun 10 23:24:47 CDT 2007


> -----Original Message-----
> From: Larsen, Peter [mailto:PLarsen at CIBER.com]
> Sent: 11 June 2007 02:12
> To: Jensas, Harald; fermbraga at gmail.com
> Cc: linux-poweredge-Lists
> Subject: RE: Reconstructing RAID-0 to RAID-10 using omconfig
> 
> First of, mirroring a Raid 0 doesn't make raid 10 -it makes raid 0+1.
> Probably the worst of all combinations (lose one disk, and *all* the
> disks in the stripe has to be restored).
> 

AFAIK the Dell LSI controller does not support RAID 0+1, it only supports RAID 0, 1, 5, 10 and 50.
This is a single disk RAID 0, it can be converted to RAID 1. And if I am not mistaken a RAID 1 can be converted to RAID 10. If this was a RAID 0 with more than on disk, it could only be expanded with more drives or be converted to a RAID 5 array by adding 1x drive.

It might be that one would have to manually reconfigure to a RAID 1 array first by doing:

omconfig storage vdisk action=reconfigure controller=0 vdisk=0 raid=r1 size=132g adisk=0:0,0:1

and then do:
omconfig storage vdisk action=reconfigure controller=0 vdisk=0 raid=r10 size=264g adisk=0:0,0:1,0:2,0:3

to get tor RAID 10.

> Second, it's pretty "easy" to rescan the SCSI bus on a live Linux
> system. Linux allows you to add and remove SCSI devices without
> rebooting by using the echo "scsi add-single-device H C I L" >
> /proc/scsi/scsi command (H = host, C = channel, I = SCSI ID, L = SCSI
> LUN). The remove-single-device command works similarily.
> 
> Once the raid controller knows about the device, the above will "find"
> it. There are also the good old "rescan-scsi-bus.sh" that'll do
> methodically through all luns/ids and "probe".
> 

Yes, but will this work if the / filesystem is located on that drive? 
Will it work, without possible filesystem damage, if any mounted filesystem is on that drive?



Regards
Harald Jensås



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