Our cluster was supplied with two IBM DS3400 RAID arrays connected with fibre channel. Both are old and one is failing so we bought an IBM V3700 to replace it. The V3700 complained that we were using the IBM's RDAC driver (true) and we were advised to change to using Linux multipath. I've done that but the default configuration for the DS3400s is: device { vendor IBM product 1726-4xx path_checker rdac features 1 queue_if_no_path hardware_handler 1 rdac prio_callout /sbin/mpath_prio_rdac /dev/%n no_path_retry 300 rr_min_io 1000 } The V3700 is still complaining and I note the "path checker rdac" and mpath_prio_rdac lines. Is this rdac the same as IBM's RDAC, and if so how can I get rid of it? OS is CentOS 5.3 (yes, I know - upgrade), filesystem is GPFS. This email and any attachments to it may be confidential and are intended solely for the use of the individual to whom it is addressed. If you are not the intended recipient of this email, you must neither take any action based upon its contents, nor copy or show it to anyone. Please contact the sender if you believe you have received this email in error. QinetiQ may monitor email traffic data and also the content of email for the purposes of security. QinetiQ Limited (Registered in England & Wales: Company Number: 3796233) Registered office: Cody Technology Park, Ively Road, Farnborough, Hampshire, GU14 0LX http://www.qinetiq.com.