Re: more then 15 partitions per SCSI device..

Brian Gerst (bgerst@quark.vpplus.com)
Tue, 02 Feb 1999 10:40:11 -0500

Luke Miller wrote:
>
> Does anyone know if there is a way to get more then 15 paritions per SCSI
> device? I have a 36 GB raid that looks like one drive /dev/sda. I have
> made more then 15 partitions /dev/sda1-/dev/sda21 and I have made the
> device files for the ones over 15, but I am not able to mount ones over
> 15. I get the following message:
>
> mount: /dev/sda16 already mounted or /u9 busy
> mount: /dev/sda17 already mounted or /ua busy
> etc...
>
> It there a hard limit of 15 partitions or is there some way around this?

Yes, there is a hardcoded limit of 15 partitions per device. From
Docuementation/devices.txt:
8 block SCSI disk devices (0-15)
...
Partitions are handled in the same way as for IDE
disks (see major number 3) except that the limit on
partitions is 15.

The real issue here is the sparse and fixed allocation of minor device
numbers. What would be /dev/sda16 is really the same device node as
/dev/sdb. You may want to check into defvs, which handles device nodes
differently, or repartition the disk with fewer partitions. [It kinda
sucks that IDE disks can have 63 partitions while SCSI can only have 15,
but this just shows one of the reasons devfs exists.]

-- 


						Brian Gerst


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