Hi, I got few servers (IBM HS20,HS21 blades, IBM xSeries 3650 & others) connected to a dual fabric san throught Qlogic HBA's (23xx, 24xx). Multipathing is done with device-mapper-multipath. On CentOS 4.x i can scan for new scsi devices without any problems, get them up with multipathing & use them without any problems. However, after i started installing CentOS 5.1 (did not notice this problem with CentOS 5) i cannot seem to rescan without huge problems. Sometimes when i rescan after presenting a new LUN to the server nothing is detected, and sometimes the device comes in without any problems at all. Sometimes i even loose some paths after rescanning.....again, i had no problems at all with CentOS 4.x. I use the Qlogic script (Dynamic Target and LUN Discovery <http://support.qlogic.com/support/EULATemplate/Template.aspx?TemplateID=9&path=http://download.qlogic.com/ms/56614/ql-dynamic-tgt-lun-disc-2.2.tgz> 2.2) to scan for new luns. Has anyone had any issues with scanning for new devices off san after upgrading to 5.1 ? Thanks, Finnur