[ILUG] SCSI

[Wynne, Conor]

Hi Lads,

Why would it be impossible? The RAID stripe set is at a layer beneath the
OS. Growing the size od the "disk" - This is raid "extention". So the
logical drive grows - and you are left with unused space on the "disk" - as
the entire raid set is seen by the OS as 1 drive - right. 

So logically, you should be able to enter fdisk or whatever your favorite
partitioner is, and create a new filesystem on this unused space - and no
reboot is necessary. The raid extention is totally hidden to any OS, so you
have no problem. 

Raid "expansion" is another matter. Find out what you controller supports. 

Someone else stated that the raid sets are seen as individual drives - or
JBODS. This is true. But they do not go into /dev/sdx. See my previous post
as to where they will go. 

Hope this helps. 
CW

--------------------
I should elorbrate a bit.

I am able to add the drive using the RAID cards config tools.

I guess what I'm really asking is there any utility I can use to help me
get the bus target and lun number??


With adding the Disk to the Array.

I have it working in that I add a drive and tell the card to grow the
array and reboot when it is finished.
And the drive now has spare space at the end.

What I would like to do is have some way of getting linux to see the new
space without rebooting.
I know this is probably impossible.

MArk

On 23 Jul 2001 15:50:36 +0100, Paul Jakma wrote:
> On 23 Jul 2001, Mark Kilmartin wrote:
> 
> > Does anybody have any experience of adding/removing a SCSI drive to a
> > system without rebooting.
> 
> yep.
> 
> echo "scsi add-single-device a b c d" > /proc/scsi/scsi
> 
> where
> 
> a = host
> b = bus
> c = target
> d = lun
> 
> eg, if you have only 1 scsi card, and say a scanner on ID 3, the
> numbers'd be:
> 
> 0 0 3 0
> 
> similarly replace the "add-" with "remove-" to remove.
> 
> > This is a system with a RAID controller in it.
> 
> ah...
> 
> > So it does support adding drives.
> 
> the RAID controller does. however purpose of a raid controller is to
> make drives 'invisible'. ie the drives are not seen as scsi devices.
> 
> > But how do I get Linux to see the drive.
> 
> how do you get the /raid controller/ to see the drive.
> 
> > Please note I'm not trying to add a drive to an existing RAID setup.
> > But an extra drive under Linux.
> 
> you'll need to use the RAID controllers setup software.
> 
> > A second related question can anybody tell me if it is possible to get
> > Linux to reconise that a Drive has grown in size so there is now space
> > at the end of a drive.(i.e. if I add an extra drive to a RAID array)
> 
> reboot.
> 
> if linux sees the extra space - great. if it doesn't - tough.
> 
> also note:
> 
> some controllers present the extra space as, yep, extra space on the
> existing RAID drive.
> 
> other controllers present the extra space as a seperate new RAID
> drive.
> 
> examine the output from your RAID driver very carefully.
> 
> > Thanks in Advance for any help.
> >
> > MArk
> 
> --paulj