Hi David. For SLES you should be using /dev/disk/by-id/36006016094511600449d92ae1937d611-part2 for a typical root partition. Regards, Wayne. -----Original Message----- From: dm-devel-bounces@xxxxxxxxxx [mailto:dm-devel-bounces@xxxxxxxxxx] On Behalf Of David Huffman Sent: Thursday, February 18, 2010 8:15 PM To: dm-devel@xxxxxxxxxx Subject: multipath: Determine which device to use for grubdevice.map file I need to configure a dm-multipath device (mpatha) as a boot disk in a script. For RHEL it appears I can put the mpath device in my device.map file. However, for SLES 11 if I use the mpath device, grub fails with "Floating point exception". For SLES I have to use the underlying path device (sd[a-z]). I know which devices make up my multipath disk. Here is an example that shows my problem. mpatha (36006016094511600449d92ae1937d611) dm-0 DGC,DISK [size=50G][features=1 queue_if_no_path][hwhandler=1 emc][rw] \_ round-robin 0 [prio=2][active] \_ 2:0:1:0 sdd 8:48 [active][ready] \_ 3:0:1:0 sdf 8:80 [active][ready] \_ round-robin 0 [prio=0][enabled] \_ 2:0:0:0 sdc 8:32 [active][ready] \_ 3:0:0:0 sde 8:64 [active][ready] Out of the 4 paths, only two (sdd and sdf) are active. This output is not very good to parse through in a script to determine which disks I can specify in my device.map file. Is there a command or better way to determine which underlying paths I can use in my device.map file. For clarification, here is a breakdown of my device.map entries and the results: (hd0) /dev/mapper/mpatha - FAIL with "Floating point exception" (hd0) /dev/sdc - FAIL with "Error 21: Selected disk does not exist" (hd0) /dev/sdd - Success!!! I would rather put the mpath device in device.map, but that does not appear to be an option for SLES. Is there a way to determine the underlying path device that is "active" and not just enabled? Right now I can run "dd if=/dev/sdc of=/dev/null bs=512 count=1 2>/dev/null; echo $?" This will tell me in the device can be written to. Any suggestions would be helpful. - David -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
