New model for managing dev_t's for partitionable block devices
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This is a problem with hotswap of course, and shouldn't be solved by the kernel putting the same device always in the same major/minor. A userspace application should query the OS and build the device nodes based upon scsi serial number, FC port WWN, or access path (host/channel/id/lun). The current "MAKEDEV" works fine for people with and ide disk and cdrom, but for real systems with lots of disks and hotswap capabilities, static naming just doesn't work (as you have said). :) Devfs solves the naming problem by using access path automatically within the OS. Downside of this methodology is that access permissions are not persistent between reboots (which is one significant limitation of devfs).
Are you aware of devfsd? It keeps permissions for you across reboots, and does it just fine.
The real limitation in this case is SCSI host numbers. There is no way to permanently assign logical controller numbers like it happens in other systems. add or remove another SCSI adapter and all your names are shifted.
which is true for any adapter not just SCSI.
-andrey
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Andrey Borzenkov (AB) writes:
AB> Are you aware of devfsd? It keeps permissions for you across AB> reboots, and does it just fine.
AB> The real limitation in this case is SCSI host numbers. There is AB> no way to permanently assign logical controller numbers like it AB> happens in other systems. add or remove another SCSI adapter and AB> all your names are shifted.
AB> which is true for any adapter not just SCSI.
one may use Inquiry/EVDP information from SCSI device