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Old 12-16-2005, 06:04 AM   #1
Registered: Jun 2005
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How do SCSI map to /dev/sd*?

does anybody know how SCSI devices on the channels map to the sda sdb etc devices?

I can cat /proc/scsi/scsi to see the devices on the channels and their id and manufacturer but this doens't tell me which one is which block device under /dev.
Old 12-16-2005, 07:55 AM   #2
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I would imagine (but don't quote me on this) that the SCSI LUN will map to the sd*. Example:

SCSI LUN 1 == sda
SCSI LUN 4 == sdb
SCSI LUN 9 == sdc

I'd break out the google-monkey for confirmation, but I believe this is how it's done. The SCSI LUN is the Logical Unique Number assigned to each drive, usually with a jumper. Number 7 tends to be the physical card/controller.
Old 12-16-2005, 08:12 AM   #3
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no because all the drive are LUN 0 in this machine which has nearly 20 SCSI disks
Old 12-16-2005, 08:21 AM   #4
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Typically, the first recognized drive (lowest SCSI id) on the first recognized controller will be sda, next sdb and so on.
Old 12-16-2005, 08:33 AM   #5
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is there any command to see the kernel's table of mappings?

this would be much easier and faster as well as knowing that you haven't made a simple mistake...


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