Unfortunately I got no reponses in my last post so I will try this again...but now is a slightly different direction. I understand the HDIO_GETGEO is an unsupported feature to dm devices....but under normal practices how would a normal end-user be able to obtain such geometry from a raw dm device? I have read of individuals looking into the MBR or grub (which sometimes resulted in incorrect results) and a few other things. But if a dba type app such as oracle needs to work with a dm created raw device...how would it normally stat for the device geometry? Any ideas? Directions? Thanks, Petros -----Original Message----- From: Peter Koutoupis Sent: Friday, July 28, 2006 4:17 PM To: 'device-mapper development' Subject: aliases as raw devices...... All, Using Redhat Advanced Server 4 Update 3 and the device-mapper/multipath-tools native to it (device-mapper-1.02.02-3.RHEL4 + device-mapper-multipath-0.4.5-12.0.RHEL4), we have a failover configuration of however many raw devices sorted by their WWID. An alias of both dm-x and the WWID number is given to that one LD of many LUN mapping. Let us say I have: /dev/sda /dev/sdb /dev/sdc /dev/sdd All being different LUN mappings of the same LD and assigned the alias of dm-0. I can obviously write to the raw device of /dev/sda or /dev/sdb and so on but I am unable to write to the raw device of /dev/dm-0. Actually to get into more detail..... dd writes to dm-0 just fine but our own coded I/O read/write utility as an issue with ioctl statting the geometry to the alias to the raw device. Oictl_status = ioctl(fd, HDIO_GETGEO, &disk_geometry_info); //part of source The IO utility comes back saying: HDIO_GETGEO error number 25 To stat a dm device what parameter would be most appropriate for ioctl to pass? Regards, Peter Koutoupis Systems Engineer Xyratex International, Inc. 1804 Centre Point Circle Suite 112 Naperville, IL 60563 USA (630)364-7656 -- dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
