Migrating from adaptec 39320 to lsi u320-2

[Scott Long]

Nico -telmich- Schottelius wrote:
> Hello guys!
> 
> I replaced the 39320 in our dell sc1425 with a lsi logic u320-2.

This is a MegaRAID controller, yes?

> 
> Now I've the problem that the u320-2 seems to export the disks to the
> OS only if one creates logical disks. If I create a logical disk it
> seems to use some bytes at the end of the harddisk to store its metadata
> on the harddisk.
> 
> The problem with that is, that the gmirror information is lost.
> 
> My question now:
> 
> - Does anyone have experiences with the u320 and knows whether it's
>   possible to use the harddisk without adding metadata to the drive?
> - Or is it possible to tell gmirror to add the metadata twice / to
>   another location? Afaics the lsi uses 2856*512 Bytes at the end of
>   the disk for metadata. So if one could put the gmirror metadata
>   at end-((2856*512)+gmirror_length), it should also work
> 
> And yes, I know that the u320-2 has hardware drive capabilities, but
> I wanted to stay with software raid, if possible, so it is no problem
> to exchange the controller later (no vendor/controller dependency makes
> life much easier).

It sounds like you've purchased a RAID controller, not a SCSI
controller.  I know that statement sounds foolish.  However, a RAID
controller is not meant to provide direct, raw access of the disk to
the OS, it's meant to provide access to storage volumes that are backed
by disks.  The controller is going put management/configuration metadata
onto certain sectors of the disk, and it's going to hide those sectors
from the OS.  That's simply how it works.

You have two options:

1.  Give up on using gmirror and use the hardware raid capabilities of
the controller that you purchased.

2.  Return your RAID controller and purchase a SCSI controller.

Scott