Maximum number of SCSI devices

steve slinthicum at
Wed May 10 14:37:34 CDT 2006

excerpt: For the Linux 2.6 kernels the number of major and minor bits
has been increased to 12 and 20 bits respectively, thus Linux 2.6
kernels can support thousands of disks. There is still the limitation of
only up to 15 partitions per disk.

On Wed, 2006-05-10 at 14:57 -0400, A Cline wrote:
> Hi folks:
> I've gotten a lot of help here over the weeks so here I am back again
> to draw water from the well.  Here's to hoping that it isn't
> dry...  :)  Please excuse me if my jargon is slightly off, I'm still
> learning. 
> We have a SAN with two storage processors (SPA, SPB).  Each server
> connecting the SAN through the fabric has two HBAs.  We also have two
> fabric switches.  So the way our fabric is configured, each server has
> 4 paths to its data.  Therefore, when I give a LUN to a server, it
> consumes 4 SCSI devices (eg. /dev/sdb, /dev/sdc, /dev/sdd, /dev/sde).
> After that, PowerPath comes along and controls which path is actually
> used by setting up a virtual device (eg. /dev/emcpowera ).  
> That's my overview.  My question is, how many SCSI devices can I
> consume on a linux box (kernel 2.6.9, RHEL4)?  I haven't been able to
> find any solid information about this online yet and I'm hoping
> someone has the answers here. 
> Thanks,
> Aaron
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