Re: lots and lots of disks again

Kurt Garloff
2004-02-16T12:40:51Z

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Hi James,

On Thu, Feb 12, 2004 at 11:43:03AM -0500, James Bottomley wrote:
> Well, I've had my ear bent about gendisk aliasing not being feasible, so
> to use the new major scheme, we'd have to have something like a boot
> time switch in the kernel and only register either the old majors or the
> new major.

This could be done. So we register one new major, with the 6bit
partitions, allowing for 1<<14 disks with 1<<6 partitions each with
one major.

It looks like in 2.7, we'll have /dev/disk anyway, it would fit in there
perfectly. Until then, the world has hopefully stepped over to udev, so
we don't need to maintain the compatibility with the old device node
numbering any more.

If we wait with this untili /dev/disk is there, we can save to register a
major for SCSI now and avoid the boot parameter.

From a distributor's perspective, I currently see demand to have many
(>1000) SCSI disks supported (*), but no serious demand for > 16 partitions,
so we would not have trouble to wait with this until 2.7/2.8.

(*) This includes needs that arise because of multipathing, most people
don't have 1000 really different LUNs exported by their SAN RAID
system.

Regards,
--
Kurt Garloff <garloff@suse.de> Cologne, DE
SUSE LINUX AG, Nuernberg, DE SUSE Labs (Head)

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