Bug#351606: multipath mis-detects SATA raid1 by default

Michael Shuey shuey at fmepnet.org
Mon Feb 6 02:35:29 UTC 2006

Package: multipath-tools
Version: 0.4.5-3

On bootup, multipath correctly handles my FC-based SAN.  However, it also 
detects the two SATA drives in the system.  Since the two drives are in a 
raid1, are physically identical, and represented by SCSI block devices 
(/dev/sd*), multipath always assumes these are a single drive with two 
valid paths, and creates a new multipath group.  Since multipath starts 
before mdadm in the default boot sequence, my software RAID isn't 
automatically started (as both block devs are already in use).

My solution was to edit /etc/udev/multipath.rules:

SUBSYSTEM=="block", BUS=="scsi", SYSFS{vendor}!="ATA", KERNEL=="sd*[!0-9]", 
ACTION=="add", RUN+="/etc/udev/scripts/multipath.sh %k"

The SATA drives show up with a vendor code of "ATA", so excluding them makes 
them nicely available for mdadm to find.  I'm not sure how portable this 
is, but it'd be nice if some sort of fix along these lines were rolled into 

Mike Shuey

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